U.S. patent application number 14/631715 was filed with the patent office on 2015-08-27 for hybrid electrodes with both intercalation and conversion materials.
The applicant listed for this patent is QuantumScape Corporation. Invention is credited to Weston Arthur Hermann, Tim Holme.
Application Number | 20150243974 14/631715 |
Document ID | / |
Family ID | 53883098 |
Filed Date | 2015-08-27 |
United States Patent
Application |
20150243974 |
Kind Code |
A1 |
Holme; Tim ; et al. |
August 27, 2015 |
HYBRID ELECTRODES WITH BOTH INTERCALATION AND CONVERSION
MATERIALS
Abstract
The disclosure set forth herein is directed to battery devices
and methods therefor. More specifically, embodiments of the instant
disclosure provide a battery electrode that comprises both
intercalation chemistry material and conversion chemistry material,
which can be used in automotive applications. There are other
embodiments as well.
Inventors: |
Holme; Tim; (Mountain View,
CA) ; Hermann; Weston Arthur; (Palo Alto,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
QuantumScape Corporation |
San Jose |
CA |
US |
|
|
Family ID: |
53883098 |
Appl. No.: |
14/631715 |
Filed: |
February 25, 2015 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
61944502 |
Feb 25, 2014 |
|
|
|
62027908 |
Jul 23, 2014 |
|
|
|
Current U.S.
Class: |
318/139 ;
320/128; 429/209; 429/218.1; 429/220; 429/221; 429/223; 429/224;
429/231.1; 429/231.3; 429/233; 429/304 |
Current CPC
Class: |
B60L 2240/549 20130101;
Y02T 10/70 20130101; B60L 50/64 20190201; H01M 10/0562 20130101;
B60L 2240/547 20130101; H01M 4/582 20130101; Y02E 60/10 20130101;
B60L 2240/545 20130101; B60L 58/12 20190201; H01M 2010/4271
20130101; H01M 4/131 20130101; H01M 4/485 20130101; H01M 4/13
20130101; H01M 10/0525 20130101; H01M 10/052 20130101; H01M 4/525
20130101; H01M 4/136 20130101; H01M 4/366 20130101; H01M 10/44
20130101; H01M 4/364 20130101; H01M 4/5825 20130101; H01M 2300/0068
20130101; H01M 2220/20 20130101; H01M 4/505 20130101 |
International
Class: |
H01M 4/36 20060101
H01M004/36; H01M 4/505 20060101 H01M004/505; H01M 4/52 20060101
H01M004/52; H02J 7/00 20060101 H02J007/00; H01M 4/136 20060101
H01M004/136; H01M 10/0562 20060101 H01M010/0562; B60L 7/10 20060101
B60L007/10; H01M 4/38 20060101 H01M004/38; H01M 4/1315 20060101
H01M004/1315 |
Claims
1. An electrochemical device comprising: an anode region; an
electrolyte region; and a cathode region comprising an
intercalation chemistry active material and a conversion chemistry
active material, wherein the electrolyte region is positioned
between the anode region and the cathode region, wherein the
conversion chemistry active material is present in the cathode
region at a weight fraction greater than about 70 w/w % of the
active material in the cathode region; wherein the intercalation
chemistry active material is present in the cathode region at a
weight fraction less than about 30 w/w % of the active material in
the cathode active region.
2. The device of claim 1 wherein the intercalation chemistry active
material and the conversion chemistry active material are
substantially segregated into two layers.
3. The device of claim 1 wherein the intercalation chemistry active
material and the conversion chemistry active material are
homogenously mixed in the cathode region.
4. The device of claim 1 wherein the intercalation chemistry active
material and the conversion chemistry active material are graded
within the cathode region such that the intercalation chemistry
active material is in higher concentration proximate to the
electrolyte.
5. (canceled)
6. The device of claim 2 wherein the intercalation chemistry active
material layer is positioned between the conversion chemistry
active material layer and the electrolyte region.
7. The device of claim 1 further comprising an anode current
collector.
8. The device of claim 1 wherein the electrolyte region is
substantially solid.
9. The device of claim 1 wherein the electrolyte region comprises a
garnet electrolyte or a sulfide electrolyte.
10. The device of claim 1 wherein the conversion chemistry active
material is selected from the group consisting of FeF.sub.2,
NiF.sub.2, FeO.sub.xF.sub.3-2x, FeF.sub.3, MnF.sub.3, CoF.sub.3,
CuF.sub.2 materials and alloys or combinations thereof.
11. (canceled)
12. The device of claim 1 wherein the intercalation chemistry
active material is selected from the group consisting of
LiMPO.sub.4 (M=Fe, Ni, Co, Mn), Li.sub.xTi.sub.yO.sub.z, wherein x
is from 0 to 8, y is from 1 to 12, z is from 1 to 24,
LiMn.sub.2O.sub.4, LiMn.sub.2-aNi.sub.aO.sub.4, wherein a is from 0
to 2, LiCoO.sub.2, Li(NiCoMn)O.sub.2, Li(NiCoAl)O.sub.2, and Nickel
Cobalt Aluminum Oxides [NCA].
13. (canceled)
14. The device of claim 1 wherein the conversion chemistry material
is characterized by a first upper voltage level and the
intercalation chemistry material is characterized by a second upper
voltage level, the first upper voltage level being lower than the
second upper voltage level.
15. The device of claim 1 wherein the conversion chemistry active
material is characterized by a conversion voltage which is lower
than the intercalation voltage of the intercalation chemistry
active material.
16. The device of claim 1 wherein the conversion chemistry active
material is characterized by a conversion voltage which is above
the intercalation voltage of the intercalation chemistry active
material.
17. (canceled)
18. The device of claim 1 wherein the conversion voltage level
during discharge of the conversion chemistry active material is
above the intercalation voltage level during discharge of the
intercalation chemistry active material.
19. The device of claim 1 wherein the cathode region comprises a
conversion material and at least two different types of
intercalation chemistry active materials.
20. The device of claim 19 wherein a first intercalation chemistry
active material has a voltage level higher than the upper voltage
level of the conversion chemistry active material and a second
intercalation chemistry active material has a voltage level lower
than the low voltage level of the conversion chemistry active
material.
21. A battery system comprising: a battery management system (BMS);
a battery pack comprising a plurality of battery cells, wherein
each of the battery cells comprises: an anode region; an
electrolyte region; and a cathode region comprising an
intercalation chemistry material active and a conversion chemistry
active material, the electrolyte region being positioned between
the anode region and the cathode region, the cathode region being
characterized by a first weight, the intercalation chemistry active
material being characterized by a second weight, the second weight
being less than 20% of the first weight.
22. (canceled)
23. The system of claim 21 wherein the BMS is configured to charge
the battery pack by pulse charges.
24. The system of claim 21 wherein: the battery system is
electrically coupled to an electric motor; and wherein the BMS
charges the battery pack when the electric motor performs
regenerative braking and the cathode region is capable of being
recharged at a voltage level greater than 4.0V.
25. The system of claim 21 wherein the cathode region is capable of
operating below a cell voltage of about 2V.
26. The system of claim 21 wherein the battery pack is
characterized by an operating temperature range of between about
-30 to 120 degrees Celsius.
27-31. (canceled)
32. An electrochemical device comprising: an anode region; an
electrolyte region; and a cathode region comprising at least one or
more intercalation chemistry active materials and a conversion
chemistry active material; wherein the weight ratio of the
conversion chemistry active material to the one or more
intercalation chemistry active materials is between 70:30 and
99:1.
33. (canceled)
34. The electrochemical device of claim 32, wherein the
intercalation voltage plateau for the one or more intercalation
materials is below the conversion voltage for the conversion
chemistry active material.
35. (canceled)
36. The electrochemical device of claim 32, wherein the operating
voltage plateau of the conversion chemistry active material is
below the upper operating voltage plateau for the intercalation
chemistry active material.
37. (canceled)
38. The electrochemical device of claim 32, wherein the upper
operating voltage plateau of the conversion chemistry active
material is between the upper operating voltage plateau and lower
operating voltage plateau for the one or more intercalation
chemistry active materials.
39. (canceled)
40. The electrochemical device of claim 32, wherein the lower
operating voltage plateau of the one or more intercalation
chemistry active materials is above the lower operating voltage
plateau for the conversion chemistry active material.
41. The electrochemical device of claim 32, wherein the lower
operating voltage of the one or more intercalation chemistry active
materials is between the upper operating voltage plateau and the
lower operating voltage plateau for the conversion chemistry active
material.
42-45. (canceled)
46. The device of claim 1 wherein the intercalation chemistry
active material comprises at least two different types of
intercalation chemistry active materials.
47. (canceled)
48. The system of claim 21 wherein the battery pack is
characterized by an operating temperature range of about 70 to 80
degrees Celsius.
49-50. (canceled)
51. The electrochemical device of claim 32, wherein the operating
voltage plateau, or upper voltage limit, of the conversion
chemistry active material is below the upper operating voltage
plateau, or upper voltage limit, of the one or more intercalation
chemistry active materials.
52-55. (canceled)
56. The electrochemical device of claim 32, wherein the lower
operating voltage plateau of the one or more intercalation
chemistry active materials is above the lower operating voltage
plateau for the conversion chemistry active material.
57. The electrochemical device of claim 32, wherein the conversion
OCV for the conversion chemistry active material is above the
intercalation voltage for the one or more intercalation chemistry
active materials.
58. The electrochemical device of claim 32, wherein the one or more
intercalation chemistry active materials are mixed with the
conversion chemistry active material and operate at a lower voltage
than the conversion OCV voltage for the conversion chemistry active
material.
59. The electrochemical device of claim 32, wherein the one or more
intercalation chemistry active materials are mixed with the
conversion chemistry active material and operate at both a higher
voltage than the intercalation regime voltage range for the
conversion chemistry active material and at a lower voltage than
the conversion OCV voltage range for the conversion chemistry
active material.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Patent
Application No. 61/944,502, filed Feb. 25, 2014, entitled HYBRID
ELECTRODES WITH BOTH INTERCALATION AND CONVERSION MATERIALS, and
U.S. Provisional Patent Application No. 62/027,908, filed Jul. 23,
2014, entitled HYBRID ELECTRODES WITH BOTH INTERCALATION AND
CONVERSION MATERIALS. Each of these provisional patent applications
is incorporated by reference herein for all purposes in their
entirety.
BACKGROUND OF THE INVENTION
[0002] Recently, with the shortage of fossil-fuels and an
increasing awareness of the adverse environmental effects from
consuming fossil-fuels, public and private sectors have researched
alternative and environmentally friendly technologies for storing
and delivering energy, some of which include rechargeable batteries
(i.e., secondary batteries, e.g., traction batteries). While many
types of rechargeable batteries have been developed, the respective
advantages and disadvantages of each type has prevented the
widespread commercialization of rechargeable batteries in many
applications, particularly automotive applications (e.g., electric
and hybrid vehicles), in part due to an inability to tailor the
energy, power, cycle-ability, and cost considerations for a given
battery to a given application.
[0003] The suitability of a particular battery type(s) for a
commercial application depends on the battery's physical and
performance characteristics as well as the cost of the constituent
materials and the associated methods of assembly. For automotive
(e.g., electric and hybrid vehicles) applications, high power and
energy capacity, wide voltage operation range, and mechanical
durability are all desirable characteristics, but unfortunately
many conventional battery devices are insufficient in at least one
of these respects for current and future automotive demands. For
electric automobiles, batteries need to demonstrate both high
energy density for long range driving and also high instantaneous
power output for acceleration and/or braking scenarios. Since most
high energy density batteries lack high power output capabilities,
conventional rechargeable batteries have not been widely adopted
for automotive applications. Therefore, new and improved battery
devices and methods of making and using the same are needed in the
field to which the instant disclosure pertains.
BRIEF SUMMARY OF THE INVENTION
[0004] The disclosure herein sets forth positive electrode
compositions for electrochemical cells which include more than one
type of positive electrode active material. In some embodiments,
these electrodes include a conversion chemistry active material and
an intercalation chemistry active material. In some of these
embodiments, the intercalation voltage for the intercalation
material may be above the conversion voltage for the conversion
chemistry material, in which case the intercalation chemistry is
utilized during recharge to provide a voltage ceiling. In some
other embodiments, the intercalation voltage for the intercalation
material may be below the conversion voltage for the conversion
chemistry material, in which case the intercalation chemistry is
utilized during discharge to provide a voltage floor. In certain
embodiments, the upper operating voltage plateau (i.e., Voltage v.
Li at full charge) of the conversion chemistry active material is
below the operating voltage plateau for the intercalation chemistry
active material, in which case the intercalation material provides
a voltage ceiling when the electrochemical cell recharges. In
certain embodiments, the upper operating voltage plateau (i.e.,
Voltage v. Li at full charge) of the conversion chemistry active
material is between the upper operating voltage plateau and lower
operating voltage plateau for the intercalation chemistry active
material, in which case the intercalation material provides a
voltage ceiling when the electrochemical cell recharges. In certain
other embodiments, the lower operating voltage plateau (i.e., lower
voltage limit, Voltage v. Li when discharged) of the intercalation
chemistry active material is above the lower operating voltage
plateau for the intercalation chemistry active material, in which
case the intercalation material provides a voltage floor when the
electrochemical cell discharges. In certain other embodiments, the
operating voltage plateau (i.e., lower voltage limit, Voltage v. Li
when discharged) of the intercalation chemistry active material is
between the upper operating voltage plateau and the lower operating
voltage plateau for the intercalation chemistry active material, in
which case the intercalation material provides a voltage floor when
the electrochemical cell discharges. In certain embodiments, the
intercalation chemistry materials that are mixed with conversion
chemistry material operate at a higher voltage than the
intercalation regime voltage range for the conversion chemistry
material. In certain other embodiments, the intercalation chemistry
materials that are mixed with conversion chemistry materials
operate at a lower voltage than the conversion regime voltage range
for the conversion chemistry material. In yet other embodiments,
the intercalation chemistry materials that are mixed with
conversion chemistry materials operate at both a higher voltage
than the intercalation regime voltage range for the conversion
chemistry material and at a lower voltage than the conversion
regime voltage range for the conversion chemistry active materials.
Also set forth herein are methods of making and using these
positive electrodes.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 shows a diagram illustrating a cathode (i.e.,
positive electrode) active material including randomly mixed
intercalation chemistry materials and conversion chemistry
materials.
[0006] FIG. 2 shows a diagram illustrating a cathode with a graded
composition.
[0007] FIGS. 3A-C show diagrams illustrating a low temperature
acceleration operation for an electrochemical cell having a
positive electrode which includes either iron trifluoride
(FeF.sub.3), only, or both iron trifluoride (FeF.sub.3) and lithium
titanate (Li.sub.4-7Ti.sub.5O.sub.12, i.e., LTO) positive electrode
active materials.
[0008] FIGS. 4A-C show diagrams illustrating a low temperature
regenerative braking operation for an electrochemical cell having a
positive electrode which includes either iron trifluoride
(FeF.sub.3), only, or both iron trifluoride (FeF.sub.3) and lithium
titanate (Li.sub.4-7Ti.sub.5O.sub.12, i.e., LTO) positive electrode
active materials.
[0009] FIGS. 5A-E illustrate a variety of operating scenarios for
electrochemical cells having positive electrodes which include
mixtures of intercalation chemistry active materials and conversion
chemistry active materials.
[0010] FIG. 6 is a table illustrating operating voltages for
different materials suitable for use in conversion chemistry
reactions.
[0011] FIG. 7 is a diagram illustrating an example battery cell
which includes a hybrid electrode having a conversion chemistry
active material and two types of intercalation chemistry active
materials according to an embodiment set forth in this
disclosure.
[0012] FIG. 8 shows an example double sided cathode electrode
suitable for use with a battery device embodiment set forth
herein.
[0013] FIGS. 9A-F show a list of intercalation materials and their
corresponding average voltage (between about 1.3-2.5V), for the
intercalated amount of Li noted in the Li subscript, that are
suitable for use with the positive electrode active materials,
e.g., conversion chemistry materials, also set forth herein.
[0014] FIGS. 10A-F show a list of intercalation materials and their
corresponding average voltage (between about 2.5-3.8V) for the
intercalated amount of Li noted in the Li subscript that are
suitable for use with the positive electrode active materials,
e.g., conversion chemistry materials, also set forth herein.
[0015] FIG. 11 shows overlaid plots of Voltage v. Discharge Run
Time, and Current v. Discharge Run Time, for electrochemical cells
having either FeF.sub.3 positive electrode active materials, only,
or a 80:20 combination of iron trifluoride (FeF.sub.3) and lithium
titanate (LTO, i.e., Li.sub.4-7Ti.sub.5.5O.sub.12) positive
electrode active materials. Cells were discharged at C/10 at
50.degree. C.
[0016] FIG. 12 shows an overlaid plot of Voltage v. Run active
mass-specific capacity (mAh/g), and Current v. Run active
mass-specific capacity (mAh/g), for electrochemical cells having
either FeF.sub.3 positive electrode active materials, only, or a
80:20 combination of iron trifluoride (FeF.sub.3) and lithium
titanate (LTO, i.e., Li.sub.4-7Ti.sub.5.5O.sub.12) positive
electrode active materials.
[0017] FIG. 13 shows an overlaid plot of Voltage v. Run Time for
electrochemical cells having either FeF.sub.3 positive electrode
active materials, only, or a 80:20 combination of iron trifluoride
(FeF.sub.3) (labeled as control-1 and control-2) and lithium
titanate (LTO, i.e., Li.sub.4-7Ti.sub.5.5O.sub.12) positive
electrode active materials (labeled as LTO-1 and LTO-2).
[0018] FIG. 14 shows a magnified perspective of FIG. 13 and
compares to LTO-1 and control-1.
[0019] FIG. 15 shows an overlaid plot of Area Specific Resistance
(ASR) v. charge-discharge Pulses for ten (10) for electrochemical
cells having either FeF.sub.3 positive electrode active materials
or a 80:20 combination of iron trifluoride (FeF.sub.3) (labeled as
control-1 through control-4) and lithium titanate (LTO, i.e.,
Li.sub.4-7Ti.sub.5 5O.sub.12) positive electrode active materials
(labeled as LTO-1 through LTO-6).
[0020] FIG. 16 shows a plot of Voltage (v. Li) as a function of Run
time (10.sup.3 seconds) for electrochemical cells having either
FeF.sub.3 positive electrode active materials, only, or a 80:20
combination of iron trifluoride (FeF.sub.3) and lithium titanate
(LTO, i.e., Li.sub.4-7Ti.sub.5.5O.sub.12) positive electrode active
materials.
[0021] FIG. 17 shows a magnified perspective of FIG. 16.
[0022] FIG. 18 shows a magnified perspective of FIG. 16.
[0023] FIG. 19 illustrates a battery power demand scenario as a
function of time for an accelerating electric vehicle.
[0024] FIG. 20 shows a simulated voltage response plot of
electrochemical cell Voltage (V v. Li) as a function of time for
electrochemical cells having LTO positive electrode active
materials, FeF.sub.3 positive electrode active materials, or a 95:5
w/w mixture of FeF.sub.3 and LTO positive electrode active
materials based on the power demand scenario in FIG. 19.
[0025] FIG. 21 shows a battery power demand scenario as a function
of time for a regeneratively braking electric vehicle.
[0026] FIG. 22 shows a simulated voltage response plot of
electrochemical cell Voltage (V v. Li) as a function of time for
electrochemical cells having LTO positive electrode active
materials, FeF.sub.3 positive electrode active materials, or a 95:5
w/w mixture of FeF.sub.3 and LTO positive electrode active
materials based on the power demand scenario in FIG. 21.
[0027] FIG. 23 shows an example electrochemical cell including a
hybrid positive electrode according to an embodiment set forth in
this disclosure.
DETAILED DESCRIPTION OF THE INVENTION
Definitions
[0028] As used herein, the phrase "active material," "active
electrode material," or "active material," refers to a material
that is suitable for use in a lithium rechargeable battery cell and
that is responsible for delivering or receiving lithium ions during
the charging and discharging cycles of the battery cell. The active
material may undergo a chemical reaction during the charging and
discharging cycles. The same battery cell may include a positive
active material and a negative active material. For examples, a
positive active material may include a metal fluoride that converts
to a metal and lithium fluoride during the discharge cycle of the
battery cell containing this material.
[0029] As used herein, the phrase "at least one member selected
from the group," includes a single member from the group, more than
one member from the group, or a combination of members from the
group. At least one member selected from the group consisting of A,
B, and C includes, for example, A, only, B, only, or C, only, as
well as A and B as well as A and C as well as B and C as well as A,
B, and C or any other all combinations of A, B, and C.
[0030] As used herein, a "binder" refers to a material that assists
in the adhesion of another material. Binders useful in the present
invention include, but are not limited to, polypropylene (PP),
atactic polypropylene (aPP), isotactive polypropylene (iPP),
ethylene propylene rubber (EPR), ethylene pentene copolymer (EPC),
polyisobutylene (PIB), styrene butadiene rubber (SBR), polyolefins,
polyethylene-co-poly-1-octene (PE-co-PO), PE-co-poly(methylene
cyclopentane) (PE-co-PMCP), stereoblock polypropylenes,
polypropylene polymethylpentene copolymer, polyethylene oxide
(PEO), PEO block copolymers, silicone, and the like.
[0031] As used herein, the terms "cathode" and "anode" refer to the
electrodes of a battery. During a charge cycle in a Li-secondary
battery, Li ions leave the cathode and move through an electrolyte
and to the anode. During a charge cycle, electrons leave the
cathode and move through an external circuit to the anode. During a
discharge cycle in a Li-secondary battery, Li ions migrate towards
the cathode through an electrolyte and from the anode. During a
discharge cycle, electrons leave the anode and move through an
external circuit to the cathode. As used herein, the cathode region
is the physical area of the electrochemical cell comprising the
cathode. As used herein, the anode region is the physical area of
the electrochemical cell comprising the anode. As used herein, the
electrolyte region is the physical area of the electrochemical cell
electrolyte the cathode.
[0032] As used herein, the term "electrolyte" refers to a material
that allows ions, e.g., Li.sup.+, to migrate therethrough but which
does not allow electrons to conduct therethrough. Electrolytes are
useful for electrically isolating the cathode and anodes of a
secondary battery while allowing ions, e.g., Li.sup.+, to transmit
through the electrolyte. As used herein, the term "electrolyte,"
also refers to an ionically conductive and electrically insulating
material. Solid electrolytes, in particular, rely on ion hopping
through rigid structures. Solid electrolytes may be also referred
to as fast ion conductors or super-ionic conductors. Solid
electrolytes may be also used for electrically insulating the
positive and negative electrodes of a cell while allowing for the
conduction of ions, e.g., Li.sup.+, through the electrolyte. In
this case, a solid electrolyte layer may be also referred to as a
solid electrolyte separator. Some electrolytes suitable for use
herein include, but are not limited to Li.sub.2S--SiS.sub.2,
Li--SiS.sub.2, Li--S--Si, and/or a catholyte consisting essentially
of Li, S, and Si, Li.sub.xSi.sub.yS.sub.z where
0.33.ltoreq.x.ltoreq.0.5, 0.1.ltoreq.y.ltoreq.0.2,
0.4.ltoreq.z.ltoreq.0.55, which may include up to 10 atomic %
oxygen, a mixture of Li.sub.2S and SiS.sub.2, in which the ratio of
Li.sub.2S:SiS.sub.2 is 90:10, 85:15, 80:20, 75:25, 70:30, 2:1,
65:35, 60:40, 55:45, or 50:50 molar ratio, Li.sub.2S--SnS.sub.2,
Li.sub.2S--SnS, Li--S--Sn, and/or a catholyte consisting
essentially of Li, S, and Sn, Li.sub.xSn.sub.yS.sub.z where
0.25.ltoreq.x.ltoreq.0.65, 0.05.ltoreq.y.ltoreq.0.2, and
0.25.ltoreq.z.ltoreq.0.65, a mixture of Li.sub.2S and SnS.sub.2 in
the ratio of 80:20, 75:25, 70:30, 2:1, or 1:1 molar ratio, which
may include up to 10 atomic % oxygen and/or may be doped with Bi,
Sb, As, P, B, Al, Ge, Ga, and/or In. Other suitable electrolytes
are found, for example, in International Patent Application No.
PCT/US2014/038283, filed May 16, 2014, and entitled SOLID STATE
CATHOLYTE OR ELECTROLYTE FOR BATTERY USING LI.sub.AMP.sub.BS.sub.C
(M=Si, Ge, AND/OR Sn), which is incorporated by reference herein in
its entirety. Other suitable electrolytes include
Li.sub.xP.sub.yS.sub.z where 0.33.ltoreq.x.ltoreq.0.67,
0.07.ltoreq.y.ltoreq.0.2 and 0.4.ltoreq.z.ltoreq.0.55, or a mixture
of Li.sub.2S:P.sub.2S.sub.5 wherein the molar ratio is 10:1, 9:1,
8:1, 7:1, 6:1 5:1, 4:1, 3:1, 7:3, 2:1, or 1:1, also
Li.sub.xP.sub.yS.sub.zO.sub.w where 0.33.ltoreq.x.ltoreq.0.67,
0.07.ltoreq.y.ltoreq.0.2, 0.4.ltoreq.z.ltoreq.0.55,
0.ltoreq.w.ltoreq.0.15. Other suitable electrolytes include
Li-stuffed garnet oxides that are characterized by a crystal
structure related to a garnet crystal structure. Li-stuffed garnets
include compounds having the formula
Li.sub.aLa.sub.bM'.sub.cM''.sub.dZr.sub.eO.sub.f,
Li.sub.aLa.sub.bM'.sub.cM''.sub.dTa.sub.eO.sub.f, or
Li.sub.aLa.sub.bM'.sub.cM''.sub.dNb.sub.eO.sub.f, where
4<a<8.5, 1.5<b<4, 0.ltoreq.c.ltoreq.2,
0.ltoreq.d.ltoreq.2; 0.ltoreq.e<2, 10<f<13, and M' and M''
are, independently in each instance, selected from Al, Mo, W, Nb,
Sb, Ca, Ba, Sr, Ce, Hf, Rb, or Ta, or
Li.sub.aLa.sub.bZr.sub.cAl.sub.dMe''.sub.eO.sub.f, where
5<a<7.7, 2<b<4, 0<c.ltoreq.2.5, 0.ltoreq.d<2,
0.ltoreq.e<2, 10<f<13 and Me'' is a metal selected from
Nb, Ta, V, W, Mo, or Sb and as described herein. "Garnets," as used
herein, also include those garnets described above that are doped
with Al.sub.2O.sub.3. Garnets, as used herein, also include those
garnets described above that are doped so that Al.sup.3+
substitutes for Li.sup.+. As used herein, Li-stuffed garnets, and
garnets, generally, include, but are not limited to,
Li.sub.7.0La.sub.3(Zr.sub.t1+Nb.sub.t2+Ta.sub.t3)O.sub.12+0.35Al.sub.2O.s-
ub.3, wherein (t1+t2+t3=subscript 2) so that the La:(Zr/Nb/Ta)
ratio is 3:2. Also, garnet and lithium-stuffed garnets as used
herein can include
Li.sub.xLa.sub.3Zr.sub.2O.sub.12+yAl.sub.2O.sub.3, where x ranges
from 5.5 to 9 and y ranges from 0 to 1. In some embodiments, x is 7
and y is 1.0. In some embodiments, x is 7 and y is 0.35. In some
embodiments, x is 7 and y is 0.7. In some embodiments x is 7 and y
is 0.4. Also, garnets as used herein can include
Li.sub.xLa.sub.3Zr.sub.2O.sub.12+yAl.sub.2O.sub.3. Exemplary
lithium-stuffed garnets are found in the compositions set forth in
International Patent Application Nos. PCT/US2014/059575 and
PCT/US2014/059578, filed Oct. 7, 2014, entitled GARNET MATERIALS
FOR LI SECONDARY BATTERIES AND METHODS OF MAKING AND USING GARNET
MATERIALS.
[0033] As used herein, the phrase "conversion chemistry active
material," or "conversion chemistry material" refers to a material
that undergoes a chemical reaction during the charging and
discharging cycles of a secondary battery. Conversion chemistry
materials useful in the present invention include, but are not
limited to, LiF, Fe, Cu, Ni, FeF.sub.2, FeO.sub.dF.sub.3-2d,
FeF.sub.3, CoF.sub.3, CoF.sub.2, CuF.sub.2, NiF.sub.2, where
0.ltoreq.d.ltoreq.0.5, and the like. Exemplary conversion chemistry
materials are found, for example, in U.S. Patent Publication No.
2014/0117291, filed Oct. 25, 2013, and entitled METAL FLUORIDE
COMPOSITIONS FOR SELF FORMED BATTERIES, and in U.S. Provisional
Patent Application No. 62/038,059, filed Aug. 15, 2014, entitled
DOPED CONVERSION MATERIALS FOR SECONDARY BATTERY CATHODES, all of
which are incorporated by reference herein in their entirety.
Exemplary conversion chemistry materials are found, for example, in
U.S. Patent Application Publication No. 2014/0170493, entitled
NANOSTRUCTURED MATERIALS FOR ELECTROCHEMICAL CONVERSION REACTIONS,
and filed Jun. 19, 2013 as U.S. patent application Ser. No.
13/922,214, the contents of which are incorporated by reference in
their entirety.
[0034] As used herein, the term "C-rate" of C/1 is defined as a
constant current cycle where the nameplate capacity is discharged
in one hour. A C-rate of C/X is defined in reference to that rate,
where the charge and discharge current is 1/X of that at C/1,
approximately corresponding to a full discharge at constant current
in X hours.
[0035] As used herein, the phrase "intercalation chemistry
material," or "intercalation chemistry active material," refers to
a material that undergoes a lithium insertion reaction during the
charging and discharging cycles of a secondary battery. For
example, intercalation chemistry materials include LiFePO.sub.4 and
LiCoO.sub.2. In these materials, Li.sup.+ inserts into and also
deintercalates out of the intercalation material during the
discharging and charging cycles of a secondary battery.
[0036] As used herein, a "metal fluoride" (MF) refers to a material
including a metal component and a fluorine (F) component. A MF can
optionally include a lithium (Li) component. In the charged state,
the MF includes a fluoride of a metal which can convert into a
lithium fluoride salt and a reduced metal, in the discharged state.
For example, the charged state MF can convert to a metal and
lithium fluoride during discharge of a battery in accordance with
the following reaction: Li+MF.fwdarw.LiF+M. MFs useful with the
disclosure herein include, but are not limited to, LiF,
Li.sub.zFeF.sub.3, Li.sub.zCuF.sub.2, Li.sub.zNiF.sub.2,
Li.sub.zCoF.sub.2, Li.sub.zCoF.sub.3, Li.sub.zMnF.sub.2,
Li.sub.zMnF.sub.3, where 0.ltoreq.z.ltoreq.3, and the like. In some
embodiments, the MF can be nanodimensioned and, in some
embodiments, the MF is in the form of nanodomains. In some
embodiments, the MF can be LiF and can further include a
nanodimensioned metal including, Fe, Co, Mn, Cu, Ni, Zr, or
combinations thereof. MFs useful in the present invention include
those set forth in U.S. Patent Application Publication No.
2014/0170493, entitled NANOSTRUCTURED MATERIALS FOR ELECTROCHEMICAL
CONVERSION REACTIONS, and filed Jun. 19, 2013 as U.S. patent
application Ser. No. 13/922,214, the contents of which are
incorporated by reference in their entirety. MFs useful in the
present invention also include those set forth in U.S. Provisional
Patent Application No. 62/038,059, entitled DOPED CONVERSION
MATERIALS FOR SECONDARY BATTERY CATHODES, and filed Aug. 15, 2014,
the contents of which are incorporated by reference in their
entirety.
[0037] As used herein, the phrase "positive electrode" refers to
the electrode in a secondary battery towards which positive ions,
e.g., Li+, conduct, flow or move during discharge of the battery.
As used herein, the phrase "negative electrode" refers to the
electrode in a secondary battery from where positive ions, e.g.,
Li+, flow or move during discharge of the battery. In a battery
comprised of a Li-metal electrode and a conversion chemistry
electrode (i.e., active material; e.g., NiF.sub.x), the electrode
having the conversion chemistry materials is referred to as the
positive electrode. In some common usages, cathode is used in place
of positive electrode, and anode is used in place of negative
electrode. When a Li-secondary battery is charged, Li ions move
from the positive electrode (e.g., NiF.sub.x) towards the negative
electrode (Li-metal). When a Li-secondary battery is discharged, Li
ions move towards the positive electrode (e.g., NiF.sub.x; i.e.,
cathode) and from the negative electrode (e.g., Li-metal; i.e.,
anode).
[0038] As used herein, the term "catholyte" refers to an ion
conductor that is intimately mixed with, or that surrounds, or that
contacts the positive electrode active material. Catholytes include
those catholytes set forth in International PCT Patent Application
No. PCT/US14/38283, entitled SOLID STATE CATHOLYTE OR ELECTROLYTE
FOR BATTERY USING Li.sub.AMP.sub.BS.sub.C (M=Si, Ge, AND/OR Sn),
filed May 15, 2014, the contents of which are incorporated by
reference in their entirety. Catholytes include those catholytes
set forth in International PCT Patent Application No.
PCT/US2014/059575, entitled GARNET MATERIALS FOR LI SECONDARY
BATTERIES AND METHODS OF MAKING AND USING GARNET MATERIALS, filed
Oct. 7, 2014, the contents of which are incorporated by reference
in their entirety.
[0039] As used herein, the phrase "about 70% w/w," refers to a
range that includes .+-.10% around the number qualified by the word
about. For example, about 70 includes 63, 64, 65, 66, 67, 68, 69,
70, 71, 72, 73, 74, 75, 76, or 77. For example, about 30 includes
27, 28, 29, 30, 31, 32, or 33.
[0040] As used herein, the phrase "substantially segregated,"
refers to a layered material in which there is an observable
distinction between one material which is separate in space from
another material. In some examples, when two or more materials are
substantially segregrated, these materials are separated in space
or segregated from each other.
[0041] As used herein, the phrase "proximate to" refers to the
relative position of two or more materials and means that the
material which is proximate to another material is closest to that
another material.
[0042] As used herein, the phrase "providing" refers to the
provision of, generation or, presentation of, or delivery of that
which is provided. Providing includes making something available.
For example, providing LiF refers to the process of making LiF
available, or delivering LiF, such that LiF can be used as set
forth in a method described herein.
[0043] The disclosure herein is directed to battery devices and
their constituent components as well as methods of making and using
the same. More specifically, embodiments set forth herein provide a
battery electrode (e.g., a positive electrode) that comprises both
intercalation chemistry materials and conversion chemistry
materials, which can be used in automotive applications. There are
other embodiments as well.
[0044] The following description is presented to enable one of
ordinary skill in the art to make and use devices and components
set forth herein and to incorporate them in the context of
particular applications. Various modifications, as well as a
variety of uses in different applications will be readily apparent
to those skilled in the art, and the general principles defined
herein may be applied to a wide range of embodiments. Thus, the
instant disclosure is not intended to be limited to the embodiments
presented, but is to be accorded the widest scope consistent with
the principles and novel features disclosed herein.
[0045] In the following detailed description, numerous specific
details are set forth in order to provide a more thorough
understanding of the disclosure set forth herein. However, it will
be apparent to one skilled in the art that the instant disclosure
may be practiced without necessarily being limited to these
specific details. In other instances, well-known structures and
devices are shown in block diagram form, rather than in detail, in
order to avoid obscuring the disclosure set forth herein.
[0046] The reader's attention is directed to all papers and
documents which are filed concurrently with this specification and
which are open to public inspection with this specification, and
the contents of all such papers and documents are incorporated
herein by reference. All the features disclosed in this
specification, (including any accompanying claims, abstract, and
drawings) may be replaced by alternative features serving the same,
equivalent or similar purpose, unless expressly stated otherwise.
Thus, unless expressly stated otherwise, each feature disclosed is
one example only of a generic series of equivalent or similar
features.
[0047] Furthermore, any element in a claim that does not explicitly
state "means for" performing a specified function, or "step for"
performing a specific function, is not to be interpreted as a
"means" or "step" clause as specified in 35 U.S.C. Section 112,
Paragraph 6. In particular, the use of "step of" or "act of" in the
Claims herein is not intended to invoke the provisions of 35 U.S.C.
112, Paragraph 6.
[0048] Please note, if used, the labels left, right, front, back,
top, bottom, forward, reverse, clockwise and counter clockwise have
been used for convenience purposes only and are not intended to
imply any particular fixed direction. Instead, they are used to
reflect relative locations and/or directions between various
portions of an object.
[0049] Under most common operating conditions (e.g., temperature
above 0.degree. C.), secondary energy storage devices that rely on
conversion chemistry cathodes can provide higher energy density and
better performance than batteries with intercalation chemistry
cathodes. For example, conversion chemistry cathodes can provide an
energy density of over 1000 mWh/g. In addition, certain types of
conversion chemistry cathode can operate at high temperature level
(e.g., over 50.degree. C., or over 80.degree. C., or over
100.degree. C.). For example, conversion chemistry material and
processes thereof are described in U.S. patent application Ser. No.
13/922,214, filed Jun. 19, 2013, entitled NANOSTRUCTURED MATERIALS
FOR ELECTROCHEMICAL CONVERSION REACTIONS, which is incorporated by
reference herein in its entirety for all purposes. For example,
conversion chemistry materials and processes thereof are described
in U.S. Provisional Patent Application No. 62/038,059, filed Aug.
15, 2014, entitled DOPED CONVERSION MATERIALS FOR SECONDARY BATTERY
CATHODES, and in U.S. Provisional Patent Application No.
62/043,353, filed Aug. 28, 2014, entitled DOPED CONVERSION
MATERIALS FOR SECONDARY BATTERY CATHODES, both provisional patent
applications of which are incorporated by reference herein in their
entirety for all purposes.
[0050] There are specific performance characteristics and operating
conditions for conversion chemistry cathodes. According to
implementations of the disclosure herein, a cathode (i.e., positive
electrode) may include active material particles with fast kinetics
(high power capability) and active material particles with slower
kinetics but high energy density. A conversion chemistry cathode
can provide a high level of energy density, but in some conditions,
low power density. For instance, at low temperature (<0.degree.
C. for example), a conversion material may have a low power density
compared to an intercalation material. In comparison, an
intercalation chemistry cathode typically has relatively low energy
density, but relatively high power density.
[0051] Thus it is to be appreciated that embodiments disclosed
herein provide positive electrodes that include conversion
chemistry particles of high energy density (e.g., FeF.sub.2,
FeO.sub.xF.sub.3-2x, FeF.sub.3, CoF.sub.3, CuF.sub.2, NiF.sub.2,
etc.), with intercalation oxide particles (e.g., LiMPO.sub.4 (M=Fe,
Ni, Co, Mn), Li.sub.xTi.sub.yO.sub.z, wherein x is from 0 to 8, y
is from 1 to 12, z is from 1 to 24, LiMn.sub.2O.sub.4,
LiMn.sub.2-aNi.sub.aO.sub.4, wherein a is from 0 to 2, LiCoO.sub.2,
Li(NiCoMn)O.sub.2, Li(NiCoAl)O.sub.2, Nickel Cobalt Aluminum Oxides
[NCA], and related intercalation oxides). Additional intercalation
oxide particles are found in U.S. Provisional Patent Application
No. 62/096,510, entitled LITHIUM RICH NICKEL MANGAGESE OXIDE, filed
Dec. 23, 2014, the contents of which are herein incorporated by
reference in its entirety for all purposes. To obtain desired
performance, conversion and intercalation materials are mixed
(e.g., homogeneously or heterogeneously depending on the
application), layered, multilayered, or graded, and operated
according to the methods set forth herein. For example, under
conditions of pulse (high power demand) regenerative charge or
pulse discharge, the power may be drawn from the intercalation
chemistry active materials. Depending on the materials selected and
co-formulated, the intercalation voltage may be above or below the
conversion voltage. If above, the intercalation chemistry is
utilized during recharge to provide a voltage ceiling, and if
below, the intercalation chemistry is utilized during discharge to
provide a voltage floor. Detailed descriptions are provided
below.
[0052] Depending on the implementation, intercalation and
conversion materials can be mixed in various ways. FIG. 1 is a
simplified diagram illustrating a cathode material comprising
randomly mixed intercalation material and conversion material
according to an embodiment of the disclosure set forth herein. This
diagram is merely an example, which should not unduly limit the
scope of the claims. One of ordinary skill in the art would
recognize many variations, alternatives, and modifications. In FIG.
1, shaded circles represent intercalation material particles, and
the unshaded circles represent conversion material particles. For
automotive applications, where batteries are used to power electric
vehicles (or hybrid vehicles with electric motors), the energy
capacity is often more important than power capacity for most
operations. As such, in some examples herein, the conversion
chemistry materials, which have a relatively higher energy capacity
than intercalation materials, are formulated as the majority
component in a hybrid positive electrode which includes both
conversion chemistry materials and intercalation chemistry
materials. For example, as shown in FIG. 1, a smaller quantity of
intercalation chemistry material is provided than the conversion
chemistry material. In some examples, the composition of a cathode
materials set forth herein has less than 20% intercalation material
with the remaining percentage being the conversion chemistry
material. Depending on the implementation, ratios between
intercalation material and conversion material may vary.
[0053] In some examples, the respective volume ratio of conversion
chemistry active material to intercalation chemistry active
material is 99:1. In some other examples, the respective volume
ratio of conversion chemistry active material to intercalation
chemistry active material is 98:2. In other examples, the
respective volume ratio of conversion chemistry active material to
intercalation chemistry active material is 97:3. In certain
examples, the respective volume ratio of conversion chemistry
active material to intercalation chemistry active material is 96:4.
In some examples, the respective volume ratio of conversion
chemistry active material to intercalation chemistry active
material is 95:5. In some other examples, the respective volume
ratio of conversion chemistry active material to intercalation
chemistry active material is 94:6. In other examples, the
respective volume ratio of conversion chemistry active material to
intercalation chemistry active material is 93:7. In certain
examples, the respective volume ratio of conversion chemistry
active material to intercalation chemistry active material is 92:8.
In some examples, the respective volume ratio of conversion
chemistry active material to intercalation chemistry active
material is 91:9. In some other examples, the respective volume
ratio of conversion chemistry active material to intercalation
chemistry active material is 90:10. In other examples, the
respective volume ratio of conversion chemistry active material to
intercalation chemistry active material is 89:11. In certain
examples, the respective volume ratio of conversion chemistry
active material to intercalation chemistry active material is
88:12. In some examples, the respective volume ratio of conversion
chemistry active material to intercalation chemistry active
material is 87:13. In some other examples, the respective volume
ratio of conversion chemistry active material to intercalation
chemistry active material is 86:14. In other examples, the
respective volume ratio of conversion chemistry active material to
intercalation chemistry active material is 85:15. In certain
examples, the respective volume ratio of conversion chemistry
active material to intercalation chemistry active material is
84:16. In some examples, the respective volume ratio of conversion
chemistry active material to intercalation chemistry active
material is 83:17. In some other examples, the respective volume
ratio of conversion chemistry active material to intercalation
chemistry active material is 82:18. In other examples, the
respective volume ratio of conversion chemistry active material to
intercalation chemistry active material is 81:19. In certain
examples, the respective volume ratio of conversion chemistry
active material to intercalation chemistry active material is
80:20. In some examples, the respective volume ratio of conversion
chemistry active material to intercalation chemistry active
material is 79:21. In some other examples, the respective volume
ratio of conversion chemistry active material to intercalation
chemistry active material is 78:22. In other examples, the
respective volume ratio of conversion chemistry active material to
intercalation chemistry active material is 77:23. In certain
examples, the respective volume ratio of conversion chemistry
active material to intercalation chemistry active material is
76:24. In some examples, the respective volume ratio of conversion
chemistry active material to intercalation chemistry active
material is 75:15. In some other examples, the respective volume
ratio of conversion chemistry active material to intercalation
chemistry active material is 74:26. In other examples, the
respective volume ratio of conversion chemistry active material to
intercalation chemistry active material is 73:27. In certain
examples, the respective volume ratio of conversion chemistry
active material to intercalation chemistry active material is
72:28. In some examples, the respective volume ratio of conversion
chemistry active material to intercalation chemistry active
material is 71:29. In some other examples, the respective volume
ratio of conversion chemistry active material to intercalation
chemistry active material is 70:30. In other examples, the
respective volume ratio of conversion chemistry active material to
intercalation chemistry active material is 69:31. In certain
examples, the respective volume ratio of conversion chemistry
active material to intercalation chemistry active material is
68:32. In some examples, the respective volume ratio of conversion
chemistry active material to intercalation chemistry active
material is 67:33. In some other examples, the respective volume
ratio of conversion chemistry active material to intercalation
chemistry active material is 66:34. In other examples, the
respective volume ratio of conversion chemistry active material to
intercalation chemistry active material is 65:35. In certain
examples, the respective volume ratio of conversion chemistry
active material to intercalation chemistry active material is
64:36. In some examples, the respective volume ratio of conversion
chemistry active material to intercalation chemistry active
material is 63:37. In some other examples, the respective volume
ratio of conversion chemistry active material to intercalation
chemistry active material is 62:38. In other examples, the
respective volume ratio of conversion chemistry active material to
intercalation chemistry active material is 61:39. In certain
examples, the respective volume ratio of conversion chemistry
active material to intercalation chemistry active material is
60:40. In some examples, the respective volume ratio of conversion
chemistry active material to intercalation chemistry active
material is 59:41. In some other examples, the respective volume
ratio of conversion chemistry active material to intercalation
chemistry active material is 58:42. In other examples, the
respective volume ratio of conversion chemistry active material to
intercalation chemistry active material is 57:43. In certain
examples, the respective volume ratio of conversion chemistry
active material to intercalation chemistry active material is
56:44. In some examples, the respective volume ratio of conversion
chemistry active material to intercalation chemistry active
material is 55:45. In some other examples, the respective volume
ratio of conversion chemistry active material to intercalation
chemistry active material is 54:46. In other examples, the
respective volume ratio of conversion chemistry active material to
intercalation chemistry active material is 53:47. In certain
examples, the respective volume ratio of conversion chemistry
active material to intercalation chemistry active material is
52:48. In some examples, the respective volume ratio of conversion
chemistry active material to intercalation chemistry active
material is 51:49.
[0054] In some examples, the respective weight ratio of conversion
chemistry active material to intercalation chemistry active
material is 99:1. In some other examples, the respective weight
ratio of conversion chemistry active material to intercalation
chemistry active material is 98:2. In other examples, the
respective weight ratio of conversion chemistry active material to
intercalation chemistry active material is 97:3. In certain
examples, the respective weight ratio of conversion chemistry
active material to intercalation chemistry active material is 96:4.
In some examples, the respective weight ratio of conversion
chemistry active material to intercalation chemistry active
material is 95:5. In some other examples, the respective weight
ratio of conversion chemistry active material to intercalation
chemistry active material is 94:6. In other examples, the
respective weight ratio of conversion chemistry active material to
intercalation chemistry active material is 93:7. In certain
examples, the respective weight ratio of conversion chemistry
active material to intercalation chemistry active material is 92:8.
In some examples, the respective weight ratio of conversion
chemistry active material to intercalation chemistry active
material is 91:9. In some other examples, the respective weight
ratio of conversion chemistry active material to intercalation
chemistry active material is 90:10. In other examples, the
respective weight ratio of conversion chemistry active material to
intercalation chemistry active material is 89:11. In certain
examples, the respective weight ratio of conversion chemistry
active material to intercalation chemistry active material is
88:12. In some examples, the respective weight ratio of conversion
chemistry active material to intercalation chemistry active
material is 87:13. In some other examples, the respective weight
ratio of conversion chemistry active material to intercalation
chemistry active material is 86:14. In other examples, the
respective weight ratio of conversion chemistry active material to
intercalation chemistry active material is 85:15. In certain
examples, the respective weight ratio of conversion chemistry
active material to intercalation chemistry active material is
84:16. In some examples, the respective weight ratio of conversion
chemistry active material to intercalation chemistry active
material is 83:17. In some other examples, the respective weight
ratio of conversion chemistry active material to intercalation
chemistry active material is 82:18. In other examples, the
respective weight ratio of conversion chemistry active material to
intercalation chemistry active material is 81:19. In certain
examples, the respective weight ratio of conversion chemistry
active material to intercalation chemistry active material is
80:20. In some examples, the respective weight ratio of conversion
chemistry active material to intercalation chemistry active
material is 79:21. In some other examples, the respective weight
ratio of conversion chemistry active material to intercalation
chemistry active material is 78:22. In other examples, the
respective weight ratio of conversion chemistry active material to
intercalation chemistry active material is 77:23. In certain
examples, the respective weight ratio of conversion chemistry
active material to intercalation chemistry active material is
76:24. In some examples, the respective weight ratio of conversion
chemistry active material to intercalation chemistry active
material is 75:15. In some other examples, the respective weight
ratio of conversion chemistry active material to intercalation
chemistry active material is 74:26. In other examples, the
respective weight ratio of conversion chemistry active material to
intercalation chemistry active material is 73:27. In certain
examples, the respective weight ratio of conversion chemistry
active material to intercalation chemistry active material is
72:28. In some examples, the respective weight ratio of conversion
chemistry active material to intercalation chemistry active
material is 71:29. In some other examples, the respective weight
ratio of conversion chemistry active material to intercalation
chemistry active material is 70:30. In other examples, the
respective weight ratio of conversion chemistry active material to
intercalation chemistry active material is 69:31. In certain
examples, the respective weight ratio of conversion chemistry
active material to intercalation chemistry active material is
68:32. In some examples, the respective weight ratio of conversion
chemistry active material to intercalation chemistry active
material is 67:33. In some other examples, the respective weight
ratio of conversion chemistry active material to intercalation
chemistry active material is 66:34. In other examples, the
respective weight ratio of conversion chemistry active material to
intercalation chemistry active material is 65:35. In certain
examples, the respective weight ratio of conversion chemistry
active material to intercalation chemistry active material is
64:36. In some examples, the respective weight ratio of conversion
chemistry active material to intercalation chemistry active
material is 63:37. In some other examples, the respective weight
ratio of conversion chemistry active material to intercalation
chemistry active material is 62:38. In other examples, the
respective weight ratio of conversion chemistry active material to
intercalation chemistry active material is 61:39. In certain
examples, the respective weight ratio of conversion chemistry
active material to intercalation chemistry active material is
60:40. In some examples, the respective weight ratio of conversion
chemistry active material to intercalation chemistry active
material is 59:41. In some other examples, the respective weight
ratio of conversion chemistry active material to intercalation
chemistry active material is 58:42. In other examples, the
respective weight ratio of conversion chemistry active material to
intercalation chemistry active material is 57:43. In certain
examples, the respective weight ratio of conversion chemistry
active material to intercalation chemistry active material is
56:44. In some examples, the respective weight ratio of conversion
chemistry active material to intercalation chemistry active
material is 55:45. In some other examples, the respective weight
ratio of conversion chemistry active material to intercalation
chemistry active material is 54:46. In other examples, the
respective weight ratio of conversion chemistry active material to
intercalation chemistry active material is 53:47. In certain
examples, the respective weight ratio of conversion chemistry
active material to intercalation chemistry active material is
52:48. In some examples, the respective weight ratio of conversion
chemistry active material to intercalation chemistry active
material is 51:49.
[0055] The mixing of intercalation and conversion materials varies.
For example, FIG. 1 shows substantially random mixing of
intercalation and conversion materials. FIG. 2 is a simplified
diagram illustrating a cathode with graded composition according to
an embodiment of the disclosure set forth herein. This diagram is
merely an example, which should not unduly limit the scope of the
claims. One of ordinary skill in the art would recognize many
variations, alternatives, and modifications. In FIG. 2, shaded
circles represent intercalation material particles, and the
unshaded circles represent conversion material particles. The
intercalation chemistry material is in much smaller amount relative
to the conversion chemistry material, and is positioned on the top
region of the cathode (i.e., the region of the cathode which
interfaces with or is most proximal to the electrolyte). For
example, by positioning intercalation materials close to the
electrolyte, the intercalation material may be accessed at higher
rates as compared to the conversion chemistry material when the
electrochemical cell is charging or discharging and lithium ions
move through the electrolyte into or out of the cathode. In various
discharging implementations, the intercalation materials are
positioned to react with incoming lithium ions before these ions
reacts with the conversion chemistry materials in the cathode. For
example, in various automotive related applications, power capacity
is important when starting an electric vehicle at low temperatures
and during pulse discharging for electric vehicle acceleration. In
these example high power capacity examples, the intercalation
materials most proximal to the electrolyte will be the first
material in the cathode to react with lithium ions, and before
these ions react with the conversion chemistry materials.
[0056] In some examples, provided is an electrochemical cell in
which the intercalation chemistry active materials in the hybrid
positive electrode are closer to, or proximal to, the electrolyte
which separates the positive and negative electrodes that is the
conversion chemistry active materials.
[0057] In certain embodiments, conversion chemistry and
intercalation chemistry materials are arranged in layers. In the
case of a graded or layered mixture, the graded chemistry can be
fabricated by slurry coating in a dual pass coater, and other
processes are possible as well. For example, if the particles are a
different size or density, the particles may be made to
preferentially segregate in the slurry during deposition and/or
drying.
[0058] In certain embodiments, conversion chemistry and
intercalation chemistry materials are arranged in layers. In some
examples, the layer in direct contact with the electrolyte is the
intercalation material and the conversion chemistry material is in
direct contact with the intercalation material but not in direct
contact with the electrolyte. In some other examples, the layer in
direct contact with the electrolyte is the conversion chemistry
material and the intercalation chemistry material is in direct
contact with the intercalation material but not in direct contact
with the electrolyte.
[0059] In certain embodiments, the positive electrode includes
alternating layers of intercalation and conversion chemistry active
materials, in which the layer most proximal to the electrolyte is
the intercalation material. In certain other embodiments, the
positive electrode includes alternating layers of intercalation and
conversion chemistry active materials, in which the layer most
proximal to the electrolyte is the conversion chemistry
material.
[0060] As a cathode material, conversion chemistry material can
provide much higher energy density than intercalation chemistry
material. For the most part, it is desirable to have as much
conversion chemistry material in the cathode as possible. The use
of intercalation chemistry material is for specific purposes in
electric vehicle applications, such as regenerative braking, lower
temperature start up, and acceleration. In portable devices as
well, low temperature operation may benefit from the introduction
of an intercalation material in a predominantly conversion
cathode.
[0061] As an example, cathodes with mixed intercalation and
conversion chemistry are especially useful in EV regenerative
braking application, especially in cold weather. In low temperature
operating environment, conversion chemistry material may have low
power capability. The intercalation chemistry material, which is
implemented as a part of cathodes, can provide the pulse power in
this condition. In addition, intercalation chemistry material can
be very useful during EV acceleration, where stored electricity is
quickly discharged, and the intercalation chemistry material can
provide the needed pulse power.
[0062] In various implementations, the cathode chemistry is
specifically configured to power the electric vehicle and works in
accordance with the powertrain voltage parameters. For example, the
power electronics of electric vehicles typically handle a voltage
ratio from the floor to ceiling of 1.5 to 2.5. By including
intercalation chemistry material (e.g., LTO material) with a
discharge potential at just above 1.5V, the voltage floor can be
raised from 1.3V to 1.5V, allowing a voltage ceiling of
2.5*1.5=3.75V instead of 2.5*1.3=3.25V. The increased voltage
ceiling can provide operating freedom and power efficiency as
needed for operating electric vehicles, especially under exacting
conditions.
[0063] As explained above, conversion chemistry materials are
characterized by a high level of energy capacity. Exemplary
conversion chemistry materials include, but not limited to,
FeF.sub.2, FeO.sub.xF.sub.3-2x, FeF.sub.3, CoF.sub.3, CoF.sub.2,
BiF.sub.3, CuF.sub.2, MnF.sub.3, NiF.sub.2, and/or other high
energy density conversion chemistry materials. In various
implementations, conversion chemistry materials may be
nanostructured materials that can provide an energy capacity of
over 1000 mWh/g. The intercalation chemistry materials are
characterized by a high level of power capacity. Exemplary
intercalation chemistry materials include lithium titanate on the
low voltage side, and on the high voltage side, lithium iron
phosphate, a spinel, an olivine, LiCoO.sub.2, NCM, NCA, and/or
other higher voltage intercalation chemistry materials. Exemplary
intercalation chemistry materials are included in the tables in
FIGS. 9 and 10.
[0064] The following example illustrates how the fraction of
intercalation material in a cathode composition may be calculated
depending on a given battery use condition. It also illustrates
that the amount of intercalation material required for extreme
applications does not significantly diminish the energy density of
the battery. An electric vehicle may require about 10 to 30 seconds
of discharge pulse power of 3.5E at 0.degree. C. A 3.5E rate means
that the battery is providing power equivalent to 3.5 times the
rated energy that would be obtained from a 1 hour continuous power
draw (i.e., discharge) that would fully discharge the battery. The
following example assumes a high power demand scenario of 30 second
pulse in which the conversion chemistry material insufficiently
supplies a fraction of the power demanded at this operating
condition (temperature and rate). In this example, for a cell rated
at 100 Wh, the pulse is a demand of roughly 3 Wh (3.5*100 W*30 s*1
hr/3600 s), or 3% of the cell energy. Therefore, 3% of the energy
of active materials would be contributed in this architecture by
the power chemistry. To work out the mass fraction contribution, if
the cathode includes a discharge power chemistry comprising
Li.sub.4Ti.sub.5O.sub.12 (LTO), which has a specific capacity of
165 mAh/g (including Li) and a 1.5V discharge potential. A 3 Wh
contribution from LTO implies that the cell must include 2 Ah
capacity of LTO (3 Wh/1.5V=2 Ah). If the 100 Wh cell includes 42 Ah
of FeF.sub.3 with a specific capacity of 601 mAh/g (including Li),
then the mass fraction of LTO is 14% of total weight (i.e., 12.1 g
vs 69.9 g). This example illustrates that a small fraction of the
battery cathode may be comprised of the fast intercalation
material, with the majority component of the cathode being a
conversion chemistry material, and meet the high power demand
contemplated in this example. Depending on the required operating
conditions, the amount of intercalation material used varies.
[0065] In another example, a battery cathode composition includes a
high voltage, fast intercalation cathode material co-formulated
with the conversion material. In this example, the specification
requires a 3E pulse charge for 10 seconds at 0.degree. C. and the
conversion material cannot deliver that charge rate, in which case
an intercalation chemistry material can be formulated with the
conversion chemistry material in order to meet the requirements of
this scenario. If LiCoO.sub.2 (LCO) is used (4V, 137 mAh/g specific
capacity including lithium) as the intercalation chemistry material
to deliver the 300 W for 10 seconds, then 208 mAh needs to be
delivered from LCO. In this example, 1.5 g of LCO is included, or a
mass fraction of about 2%. The mass fraction is lower in this
example because a shorter pulse is required, and because the
voltage of LCO is higher, so the specific energy is higher, and a
smaller mass is required to deliver that energy. As demonstrated in
the above two examples, the amount and types of intercalation
material used depends on many factors, such as characteristics of
the intercalation chemistry material, conversion chemistry
material, expected operating condition, desired tolerance, energy
and power requirements of electric vehicles, and other factors.
[0066] For certain example electric vehicle applications, the high
voltage intercalation chemistry materials has a charge voltage
greater than the low rate, high temperature charge potential of the
conversion chemistry material (e.g., around 3.7V in the case of
FeF.sub.3), but lower than the system high voltage cutoff (around
4.2V in some cases). Examples of high voltage materials that can be
used are LiMPO.sub.4 (M=Co, Ni, Mn, Fe, and combinations thereof),
LiNi.sub.0.5Mn.sub.1.5O.sub.4, LiMn.sub.0.5Ni.sub.0.5O.sub.2,
LiMn.sub.2O.sub.4, LiCoO.sub.2, and Li.sub.3V.sub.2PO.sub.4.
Additional high voltage materials are listed in FIGS. 10A-10F.
Low-voltage intercalation chemistry materials are to have a
discharge potential greater than the system low voltage cutoff
(around 1.3V in some cases) but lower than the high temperature,
low rate discharge potential of the conversion chemistry material
(2.4V in the case of FeF.sub.3). Examples of lower voltage
materials that can be used are Li.sub.4Ti.sub.5O.sub.12. Additional
low voltage materials are listed in FIGS. 9A-9F. In some examples
set forth herein, the conversion chemistry material is
co-formulated with both a low-voltage intercalation chemistry
material and also a high-voltage intercalation chemistry material.
In some examples set forth herein, the conversion chemistry
material is co-formulated with an intercalation chemistry material
listed in the tables in FIGS. 9A-F and also with an intercalation
chemistry material listed in the tables in FIGS. 10A-F.
[0067] As described above, the intercalation chemistry materials
and conversion chemistry materials are synergistic in at least one
respect. A low voltage intercalation chemistry material like LTO
can provide the discharge energy on a discharge pulse (e.g., high
power demand pulse or acceleration), and it can then be recharged
by the conversion chemistry material (e.g., FeF.sub.3) as the pulse
completes. The processed can be used repeatedly, for each discharge
pulse, so long as the discharge pulses are spaced sufficiently
temporally apart to allow the low voltage intercalation chemistry
material (e.g., LTO) to recharge. In a preferred embodiment, only
enough LTO needs to be included in the hybrid positive electrode to
provide energy for the single longest expected discharge pulse.
[0068] FIG. 3 is a simplified diagram illustrating operation of a
mixed material cathode according to embodiments of the disclosure
set forth herein at low temperature where the electric vehicle
accelerates. This diagram is merely an example, which should not
unduly limit the scope of the claims. One of ordinary skill in the
art would recognize many variations, alternatives, and
modifications. FIG. 3A shows an example power demand of a vehicle
at low temperature (e.g., 0.degree. Celsius). FIG. 3B shows voltage
output, as a function of time, for a battery cell comprising a
conversion chemistry material (e.g., FeF.sub.3 or other types of
conversion chemistry material). FIG. 3C shows voltage output t, as
a function of time, for a battery cell comprising both conversion
chemistry materials and intercalation chemistry materials (e.g.,
LTO or other types of intercalation materials).
[0069] As shown in FIG. 3A, in some examples, the power demand for
an electric vehicle is substantially constant, except when the
electric vehicle accelerates at time 301A and 302A, when the power
demand peaks. Depending on the state of charge, the battery cells
for the electric vehicle may or may not have enough power to
satisfy the power demand when the electric vehicle accelerates. As
shown in FIG. 3B, the cell voltage of the battery cells for the
electric vehicle gradually drops below the operating lower voltage
cutoff, as the electric vehicle operates, from the initially high
voltage level (close to upper voltage cutoff level) to low voltage
level (close to the lower voltage cutoff level), when the cathode
only includes a conversion chemistry material (e.g., FeF.sub.3
and/or other types of conversion chemistry materials). However, and
as shown in FIG. 3C, when the cathode also includes a low voltage
intercalation material, the lower voltage cut-off is railed. In
FIG. 3C, the battery voltage does not drop below the lower voltage
cut-off because the intercalation material maintains a higher cell
voltage that would be possible if only the conversion chemistry
material was present.
[0070] Depending on the state of charge and the type of conversion
material, the battery cell with conversion chemistry material may
operate under two regimes. When the battery charge is substantially
full, the battery cell operates in an intercalation (fast) regime.
That is, the conversion chemistry material discharges with
intercalation processes. During the intercalation regime, the cell
voltage is relatively high and has enough headroom to provide the
power and voltage needed at time 301B. At time 301B, the drop in
voltage corresponding to electric vehicle acceleration at time 301A
does not cause the cell voltage level to drop below the lower
voltage cutoff, and the electric vehicle operates normally.
[0071] However, when the battery cell operates in the conversion
regime (i.e., the conversion material is discharging or charging by
way of a conversion chemistry reaction and not by way of an
intercalation chemistry reaction) as shown in FIG. 3B between time
301B and 302B, the battery cell voltage is substantially constant,
but is at a lower level, which can be close to lower voltage cutoff
level. When the electric vehicle accelerates, during time 302A, the
increased power demand may cause the cell voltage to drop below the
lower voltage cutoff level, as shown in time 302B. When the voltage
level of the battery cell falls below the lower voltage cutoff, the
cell cannot deliver the required power. When the battery cell (or
the battery pack made of a large of battery cells) is not above the
lower voltage cutoff level, it cannot meet the power demand, and as
a result, the electric vehicle cannot accelerate as needed.
[0072] When the cathode includes both intercalation and conversion
chemistry materials, the operation of the electric vehicles is
significantly improved, as demonstrated in FIG. 3C. The graph in
FIG. 3C shows the cell voltage for a battery cathode having both
intercalation chemistry materials (e.g., LTO) and conversion
chemistry material (e.g., FeF.sub.3). As explained above, other
types of intercalation chemistry materials and conversion chemistry
materials can be used as well. At time 301C, the cell voltage is
well above the lower voltage cutoff level, and thus even when the
acceleration at time 301A causes the cell voltage level to drop,
the cell voltage level is still well above the lower voltage cutoff
level. At time 302C, the cell, which primarily comprises (e.g.,
over 80% of total weight) conversion chemistry materials, is
operating in the conversion regime. At time 302C, the cell voltage
is close to the lower voltage cutoff level. The intercalation
chemistry material, at time 302C, provides much needed power to
when the electric vehicle operates at time 302A, thereby preventing
the cell voltage to drop below the lower voltage cutoff at time
302C and allowing the electric vehicle to accelerate as needed. For
example, the lower voltage cutoff level is about 1.5V. At around
1.5V, the intercalation chemistry material contributes to the power
needed by the electric vehicle. Cell voltage is "railed" or
otherwise stabilized at the voltage level attributed to the
intercalation material, and the battery back as a whole can satisfy
the power demand of the electric vehicle for acceleration. It is to
be noted that when the electric vehicle accelerates, the increased
power demand causes the cell voltage to drop. When the acceleration
stops and power demands decreases, the conversion chemistry
material can discharge and thereby recharge the intercalation
chemistry material. As mentioned above, the intercalation material
is specifically configured to provide operating headroom in
situations such as time 302C, and only makes up a small portion of
battery cell cathode. Thus, the intercalation material is recharged
when possible, and the recharged intercalation material can provide
supplemental power at a later time when needed.
[0073] FIG. 4 is a simplified diagram illustrating operation of a
mixed material cathode at low temperature when the electric vehicle
performs regenerative braking. This diagram is merely an example,
which should not unduly limit the scope of the claims. One of
ordinary skill in the art would recognize many variations,
alternatives, and modifications. FIG. 4A shows the power demand as
a function of time for regenerative braking of a vehicle at low
temperature (e.g., 0.degree. Celsius). For example, the vehicle can
be an electric vehicle or a hybrid vehicle. FIG. 4B shows voltage
output, as function of time, for a battery cell whose cathode
comprises a conversion chemistry material (e.g., FeF.sub.3 or other
types of conversion chemistry material). FIG. 4C shows voltage
output, as a function of time, for a battery cell whose cathode
comprises both conversion chemistry materials and intercalation
chemistry materials (e.g., LTO or other types of intercalation
materials).
[0074] As shown in FIG. 4A, power demand from the vehicle, under
0.degree. C. isothermal condition, is substantially constant,
except during time 401A and time 401B when the vehicle is braking
During time 401A and 401B, the power demand is low and negative, as
the regenerative braking process generates power from the braking
process, and the power from the regenerative braking process can be
used to charge the battery. In FIG. 4B, the graph shows operation
of a battery cell comprising a conversion chemistry material (e.g.,
FeF.sub.3 or other types of conversion chemistry materials). The
conversion-chemistry-only battery cell in FIG. 4B operates in two
regimes: initially in the intercalation regime and then later in
time, as the voltage drops, in the conversion regime. During the
intercalation regime, the cell voltage starts relatively high and
is close to the upper voltage cutoff level. For example, the upper
voltage cutoff level may be around 4.2V. As vehicle operation
drains the battery cell, the cell voltage drops, until the battery
cell starts operating in the conversion region. During time 401B,
which corresponds to time 401A of generative braking, the cell
voltage goes up as the battery is recharged by the regenerative
braking process. Since the cell voltage level at time 401B is
relatively high and close to the upper voltage cutoff level, the
recharging of the battery from the regenerative braking process
spikes up the cell voltage to a level above the upper voltage
cutoff level. While recharging of the battery cell is generally
desirable, the battery cell cannot accept the recharging once the
voltage is above the upper level cutoff. In addition to wasting the
power from regenerative braking recharge, the power over the upper
voltage cutoff level can lead to unsafe operating condition for the
battery cell. When the battery cell operates in conversion regime,
the voltage level is relatively low, cell voltage spike at time
402B does not pose the same type of problem as when the cell
voltage is high and close to the high voltage cutoff.
[0075] FIG. 4C shows the benefit of a battery cell that includes
both intercalation chemistry and conversion chemistry materials.
For example, intercalation chemistry material include, but are not
limited to LCO material, and the conversion chemistry material
include, but are not limited to, FeF.sub.3 material. Other
materials are possible as well. At time 401C, which corresponds to
time 401A, battery cell is recharged from the regenerative braking,
but the cell voltage does not go over the upper voltage cutoff
level (e.g., 4.2V). This is because when the voltage level goes
above 4.2V, the intercalation chemistry material (e.g., LCO
material) accepts the regenerative power. Voltage is "railed" at
the upper voltage cutoff level, because the power over 4.2V is
absorbed by the intercalation chemistry material; in other words,
the intercalation chemistry material is charged at time 401C. Since
the intercalation chemistry material absorbs the power when voltage
is at or above the upper voltage cutoff level, the potentially
unsafe operating condition of voltage over 4.2V is avoided at time
401C. The intercalation chemistry material can be partially charged
during time 402C, but is it not necessarily so for the purposed of
keeping voltage level below the upper voltage cutoff level.
[0076] Depending on the application, a cathode may include, in
addition to a conversion chemistry material, two or more
intercalation chemistry materials. The two intercalation chemistry
materials have different operating voltages, which can widen the
range of operating conditions. For example, the two intercalation
chemistry materials include a first intercalation material that is
characterized by a voltage plateau lower than that of the second
intercalation material and the conversion chemistry material but
above the system cutoff voltage. The second intercalation material
is characterized by a voltage plateau higher than that of the first
intercalation material and the conversion chemistry material but
lower than the system cutoff voltage. In a specific embodiment, the
first intercalation material includes Li.sub.4Ti.sub.5O.sub.12 or
other lithium titanate, and its voltage plateau is about 1.5V vs
Li; the second intercalation material includes LiCoO.sub.2 or other
lithium cobalt oxide, and its voltage plateau is about 4V vs Li. A
cathode with two intercalation chemistry materials and a conversion
chemistry material can therefore have an operating voltage range of
about 1.5 to 4.2V.
[0077] As shown in the FIGS. 3-4 and described above, conversion
chemistry materials, depending on voltage and/or state of charge,
operate in both an intercalation regime and a conversion regime. It
is to be understood that when operating in intercalation regime,
the conversion chemistry material has a first voltage range, and
when operating in the conversion regime, the conversion chemistry
material has a second voltage range that is different from the
first voltage range. For example, the conversion chemistry material
CoF.sub.3 has a voltage range of about 3-5V during intercalation
regime, and a voltage range of about 1.6-2.4V during the conversion
regime. As an example, iron fluoride is a conversion chemistry
material that operates in both the intercalation regime and the
conversion regime.
Li.sup.++FeF.sub.3+e.sup.-=LiFeF.sub.3(intercalation)
2Li.sup.++LiFeF.sub.3+2e.sup.-=3LiF+Fe(conversion)
[0078] With iron fluoride, the intercalation reaction is typically
at a voltage of about 2.7-4V, and the conversion reaction is
typically at a voltage below 2.4V. Other types of conversion
chemistry materials have their respective intercalation and
conversion voltages, where the intercalation regime voltage range
is higher than the conversion regime voltage range. According to
certain embodiments set forth herein, intercalation chemistry
materials that are mixed with conversion chemistry material operate
at a higher voltage than the intercalation regime voltage range
and/or a lower voltage than the conversion regime voltage
range.
[0079] FIGS. 5A-E are simplified diagrams illustrating operating
scenarios of cathode with mixed conversion and intercalation
materials according to embodiments of the disclosure set forth
herein. These diagrams merely provide an example, which should not
unduly limit the scope of the claims. One of ordinary skill in the
art would recognize many variations, alternatives, and
modifications. Conversion materials, during discharge, may be
characterized by one or two voltage plateaus or levels. A voltage
plateau is a region on a plot of voltage versus charge with a
gradual slope during a low-rate (e.g. constant current rate of C/10
or slower) discharge. FIG. 5A illustrates a nonlimiting example
voltage versus charge curve of a conversion material that has an
intercalation voltage regime and a conversion voltage (lower)
regime and a second material with an intercalation voltage between
the two voltage regimes of the conversion material. FIG. 5B
illustrates a nonlimiting example intercalation material with a
voltage plateau below the conversion potential of the conversion
material, an arrangement that may help in conditions of low
temperature acceleration at low state of charge (SOC). FIG. 5C
shows an intercalation material with a voltage plateau above the
high voltage of the intercalation material, an arrangement that may
help in conditions of low temperature regenerative breaking at high
SOC. FIG. 5D shows two intercalation materials with voltage
plateaus bracketing the conversion material conversion voltage.
FIG. 5E shows two intercalation materials, one with a voltage
plateau above the intercalation regime of the conversion material
and another with a voltage plateau below the conversion plateau of
the conversion material.
[0080] It is to be appreciated that there are many types of
conversion chemistry and intercalation chemistry materials, and
different materials have different operating conditions, such as
operating temperature, operating voltage, and others. FIG. 6 is a
table illustrating operating voltages of different metal materials
in conversion reactions. Thermodynamic calculations and tables such
as FIG. 6 may be used to determine approximate voltages of
conversion materials, while experiments may be required to
demonstrate the voltages empirically. FIG. 6 may therefore be used
to design a hybrid intercalation/conversion positive electrode by
selection of intercalation materials with the appropriate voltage
plateaus.
[0081] FIG. 7 is a simplified diagram illustrating a battery cell
according to an embodiment of the disclosure herein. This diagram
is merely an example, which should not unduly limit the scope of
the claims. One of ordinary skill in the art would recognize many
variations, alternatives, and modifications. As shown in FIG. 7,
the battery cell 700 includes current collectors 705 and 704, anode
703, electrolyte 702, and cathode 701. Cathode 701 includes three
layers of materials: conversion material 701C, first intercalation
material 701A, and second intercalation material 701B. In some
examples, the first intercalation material 701A has a lower voltage
plateau than the lower voltage of the conversion material and is
positioned closer to the electrolyte 702 relative to the second
intercalation material 701B and the conversion material 701C. The
second conversion material 701B has a higher voltage plateau than
the upper voltage of the conversion material, and is positioned
between the first intercalation material 701A and the conversion
material 701C. In various implementations, the first intercalation
material 701A has a lower voltage and therefore would likely be
subjected to higher current density than the second intercalation
material 701B and the conversion material 701C, and therefore needs
closer ionic access to the electrolyte 702.
[0082] FIG. 23 is a simplified diagram illustrating a battery cell
according to an embodiment of the disclosure herein. This diagram
is merely an example, which should not unduly limit the scope of
the claims. One of ordinary skill in the art would recognize many
variations, alternatives, and modifications. As shown in FIG. 23,
the battery cell 2400 includes current collectors 2402 and 2407,
negative electrode 2406, electrolyte 2405, and positive electrode
2401. Positive electrode 2401 includes two layers of materials:
conversion material 2403 and intercalation material 2404. In some
examples, the intercalation material 2404 has a lower voltage
plateau than the lower voltage of the conversion material and is
positioned closer to the electrolyte 2405 than the conversion
material 2403. In some other examples, the intercalation material
2404 has a higher voltage plateau than the higher voltage of the
conversion material and is positioned closer to the electrolyte
2405 than the conversion material 2403.
[0083] FIG. 8 shows an example cathode electrode suitable for use
with the battery devices set forth herein. In FIG. 8, a current
collector for a cathode has cathode active materials on two
opposing sides of the current collector. These cathode active
materials can include conversion chemistry materials, intercalation
chemistry materials, both conversion chemistry materials and
intercalation chemistry materials, more than one type of
intercalation material, conversion chemistry materials and more
than one type of intercalation material, or combinations of these
options. A catholyte may also be included with these cathode active
materials. In some examples, as described below, different types of
conversion chemistry materials are used on each opposite side of
the current collector. In some examples, the thickness of the
cathode on one side of the current collector is not equal to the
thickness of the cathode on the other side of the current
collector, as shown in FIG. 8. In some examples, one side of the
current collector has a thicker layer of cathode active materials
than the layer of cathode active materials on the other side of the
current collector.
[0084] FIG. 9 (presented as FIGS. 9A-9F) shows a list of
intercalation materials with discharge voltages between about
1.3-2.5V that are suitable for use with the cathode active
materials, e.g., conversion chemistry materials, also set forth
herein. In some examples, the compositions set forth herein include
at least one or more intercalation materials with discharge
voltages between about 1.8-2.1V in combination with conversion
chemistry materials, e.g., metal fluorides.
[0085] FIG. 10 (presented as FIGS. 10A-10F) shows a list of
intercalation materials with discharge voltages between about
2.5-3.8V that are suitable for use with the cathode active
materials, e.g., conversion chemistry materials, also set forth
herein. In some examples, the compositions set forth herein include
at least one or more intercalation materials with discharge
voltages between about 2.5-3.8V in combination with conversion
chemistry materials, e.g., metal fluorides, nickel fluorides.
[0086] In some examples, the compositions set forth herein include
at least one or more intercalation materials with discharge
voltages between about 1.8-2.1V in combination with at least one or
more intercalation materials with discharge voltages between about
2.5-3.8V and in combination with conversion chemistry materials,
e.g., metal fluorides, nickel fluorides, iron fluorides.
Example Combinations of Conversion Chemistry and Intercalation
Chemistry Materials in Cathode
[0087] In some examples set forth herein, the hybrid electrodes
include a conversion chemistry material, described in this
application, in combination with at least one intercalation
material that is an oxide or a phosphate or both. In some examples,
these oxides or phosphates are selected from the materials listed
in the table in FIG. 9 (presented in the form of multiple sheets
labeled FIGS. 9A-9F). In some examples, these intercalation
materials have discharge voltages between 1.3 and 2.5V. In some
other examples, these intercalation materials have discharge
voltages between 1.8 and 2.1V. In some of these examples, the
conversion material combined with these intercalation materials is
iron fluoride.
[0088] In some examples, these oxides or phosphates are selected
from the materials listed in the table in FIG. 10. In some
examples, these intercalation materials have discharge voltages
between 2.5 and 3.0V. In some of these examples, the conversion
material combined with these intercalation materials is nickel
fluoride. In some of these examples, the conversion material
combined with these intercalation materials is iron fluoride. In
some of these examples, the conversion material combined with these
intercalation materials is a combination of nickel fluoride and
iron fluoride (e.g., FeF.sub.3).
[0089] In some examples, when the conversion chemistry material is
nickel fluoride the combined intercalation chemistry materials have
discharge voltages between 2.5 and 3.0V.
[0090] In some examples, the hybrid electrode includes a metal
fluoride as the conversion chemistry material (e.g., NiF.sub.2,
FeF.sub.3, or combinations thereof) and a member selected from the
group consisting of TiS.sub.2, FeS, FeS.sub.2, CuS, LTO (e.g.,
LiTiO.sub.2, or Li.sub.4-7Ti.sub.5O.sub.12, or
Li.sub.4Ti.sub.5O.sub.12 i.e., lithium titanate or LTO), and
combinations thereof. In some of these examples, the metal fluoride
is a member selected from the group consisting of FeF.sub.3,
CuF.sub.2, NiF.sub.2, and combinations thereof. In some of these
examples, the metal fluoride is a member selected from the group
consisting of iron fluoride, copper fluoride, nickel fluoride, and
combinations thereof. In some of these examples, the metal fluoride
is doped with Cu, Ni, Li.sub.2O, a transition metal oxide, or
combinations thereof. In some examples, the hybrid electrode
includes FeF.sub.3 and an intercalation material in FIGS. 9A-F, in
FIGS. 10A-F, or intercalations materials selected from both FIGS.
9A-F and FIGS. 10A-F.
[0091] In some examples, the hybrid electrode includes FeF.sub.3
and TiS.sub.2. In some examples, the hybrid electrode includes
FeF.sub.3 and FeS. In some examples, the hybrid electrode includes
FeF.sub.3 and FeS.sub.2. In some examples, the hybrid electrode
includes FeF.sub.3 and CuS. In some examples, the hybrid electrode
includes FeF.sub.3 and LTO (i.e., a lithium titanate). In some
examples, the hybrid electrode includes FeF.sub.3 and
Li.sub.0-1TiO.sub.2. In some examples, the hybrid electrode
includes FeF.sub.3 and Li.sub.0-1FeCuS.sub.2.
[0092] In some of these examples, FeS has a discharge voltage at
1.6V vs. Li. In some examples, FeS.sub.2 has a discharge voltage at
about 1.5V-1.8V vs. Li. In some examples, CuS has a discharge
voltage at about 1.7-2.05V vs. Li. In some examples, TiS.sub.2 has
a discharge voltage at 1.6-2.2V vs. Li. In some examples, LTO has a
discharge voltage at 1.5V vs. Li.
[0093] In some of these examples, a catholyte is included with
these cathode combinations of conversion chemistry materials and
intercalation chemistry materials. In some examples, the catholyte
is a lithium, phosphorus, and sulfur containing specie. In some
examples, the catholyte comprises a lithium, phosphorus, and sulfur
containing specie. In some examples, the catholyte is a lithium
stuffed garnet. In some examples, the catholyte is a lithium
stuffed garnet doped with alumina. In some examples, the catholyte
is a lithium silicon sulfide. In some examples, the catholyte
comprises a lithium silicon sulfide. In some examples, the
catholyte comprises a lithium, phosphorus, tin, silicon sulfide.
Suitable catholyte materials may be found in International PCT
Patent Application No. PCT/US14/38283, entitled SOLID STATE
CATHOLYTE OR ELECTROLYTE FOR BATTERY USING Li.sub.AMP.sub.BS.sub.C
(M=Si, Ge, AND/OR Sn), filed May 15, 2014, the entire contents of
which are herein incorporated by reference for all purposes.
[0094] In some examples, the cathode includes FeF.sub.3, a
catholyte, and an intercalation material with a discharge voltage
between 1.8 and 2.1V vs. Li. In some examples, the cathode includes
FeF.sub.3, a catholyte, and an intercalation material with a
discharge voltage of about 2.0V vs. Li. In some examples, the
cathode includes FeF.sub.3, a catholyte, and an intercalation
material with a discharge voltage of 2.0V vs. Li. In some examples,
the cathode includes FeF.sub.3, a catholyte, and an intercalation
material with a discharge voltage of about 1.3-2.5V vs. Li. In some
examples, the cathode includes FeF.sub.3, a catholyte, and an
intercalation material with a discharge voltage of about 1.8-2.1V
v. Li. In some examples, the cathode includes FeF.sub.3, a
catholyte, and an intercalation material selected from a member in
the table in FIG. 9 or combinations of the members in the table in
FIG. 9.
[0095] In some examples, the hybrid electrode includes NiF.sub.2
and Li.sub.0-1FeO.sub.2. In some examples, the hybrid electrode
includes NiF.sub.2 and Li.sub.0-1MnO.sub.2. In some examples, the
hybrid electrode includes NiF.sub.2 and Li.sub.1.33-2CuO.sub.2. In
some examples, the hybrid electrode includes NiF.sub.2 and an
intercalation material in FIG. 10.
Double-Side Coated Electrode
[0096] In some examples, the battery device set forth herein
includes a double-side coated electrode with one side of the
current collector foil coated with a thicker electrode and the
other side coated with a thinner electrode. For example, FIG. 8
illustrates a non-limiting example of such a double-sided coated
electrode. In some examples, the thicker electrode is a metal
fluoride with a conversion plateau higher than the discharge
voltage of the cathode active material of the thinner
electrode.
[0097] In some examples, the combination of intercalation chemistry
materials and conversion chemistry materials includes metal
fluorides as the conversion chemistry material. In some examples,
both sides of the double-side coated electrode include conversion
chemistry materials and intercalation chemistry materials. In some
examples, both sides of the double-side coated electrode include
conversion chemistry materials and intercalation chemistry
materials, but each side of the double-side coated electrode has a
different type of conversion chemistry material. In some of these
examples, one side has a metal fluoride, and the other side has a
doped metal fluoride. In some examples, both sides of the
double-side coated electrode include conversion chemistry materials
and intercalation chemistry materials, but each side of the
double-side coated electrode has a different amount of conversion
chemistry material.
[0098] In some examples, both sides of the double-side coated
electrode include conversion chemistry materials and intercalation
chemistry materials, but each side of the double-side coated
electrode has a different type of intercalation chemistry material.
In some examples, both sides of the double-side coated electrode
include conversion chemistry materials and intercalation chemistry
materials, but each side of the double-side coated electrode has a
different amount of intercalation chemistry material.
[0099] In some examples, both sides of the double-side coated
electrode include conversion chemistry materials and intercalation
chemistry materials, but each side of the double-side coated
electrode has a different type of conversion chemistry material and
of intercalation chemistry material. In some examples, both sides
of the double-side coated electrode include conversion chemistry
materials and intercalation chemistry materials, but each side of
the double-side coated electrode has a different amount of each
type of conversion chemistry material and intercalation chemistry
materials.
[0100] In yet other examples, one side of the double-side coated
electrode includes a conversion chemistry material and the other
side of the double-side coated electrode includes an intercalation
chemistry material.
[0101] In some examples, the thicker electrode side includes a
doped conversion material that has a higher, for example, 50-200 mV
higher, discharge conversion plateau than the thinner electrode.
This architecture surprisingly provides a driving force for
"recharging" the thinner electrode after it is depleted in a pulse
or low temperature power event.
[0102] In some examples, one or both sides of the double-side
coated cathode is graded. In some examples, one or both sides of
the double-side coated cathode is a two-layer single electrode.
[0103] In some examples, one or both sides of the double-side
coated cathode is a two-layer single electrode where the layer in
immediate contact with the current collector includes a "doped"
conversion material with a higher voltage conversion plateau than
the other cathode active material. In this architecture, the
undoped conversion material serves as the "power" layer. In some
examples of this architecture, the open circuit voltage difference
between these layers provides an enthalpic driving force for one
layer of the cathode to recharge the other layer of the
cathode.
Nanodimensioned Conversion Chemistry and Intercalation Chemistry
Materials in Cathode
[0104] In some examples set forth herein, either the conversion
chemistry material or the intercalation chemistry material, or
both, are nanodimensioned. In some examples, the conversion
chemistry material is nanodimensioned and described as particles or
grains of conversion chemistry material wherein the particles or
grains have a d.sub.50 diameter of about 1, 2, 3, 4, 5, 6, 7, 8, 9,
10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26,
27, 28, 29, or 30 nm. In some examples, the intercalation chemistry
material is nanodimensioned and described as particles or grains of
intercalation chemistry material wherein the particles have a
d.sub.50 diameter of about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,
13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
or 30 nm. In some examples, these nanodimensioned particles of
conversion chemistry materials and intercalation chemistry
materials are intimately mixed together.
[0105] As used herein, d.sub.50 refers to the median diameter or
the median size, in a distribution of sizes, measured by microscopy
techniques, such as, but not limited to, scanning electron
microscopy. As used herein, d.sub.50 includes the characteristic
dimension at which 50% of the particles are smaller than the
recited size.
[0106] As used herein, d.sub.50 is measured by light scattering,
for example, on a Horiba LA-950 V2 particle size analyze using
acetonitrile as a solvent and one-minute sonication before
measurement.
[0107] In some examples, the grains of conversion chemistry
materials that are mixed with intercalation chemistry materials
have a d.sub.50 of 1 nm. In some other examples, the grains of
conversion chemistry materials that are mixed with intercalation
chemistry materials have a d.sub.50 of 2 nm. In other examples, the
grains of conversion chemistry materials that are mixed with
intercalation chemistry materials have a d.sub.50 of 3 nm. In still
other examples, the grains of conversion chemistry materials that
are mixed with intercalation chemistry materials have a d.sub.50 of
4 nm. In yet other examples, the grains of conversion chemistry
materials that are mixed with intercalation chemistry materials
have a d.sub.50 of 5 nm. In some examples, the grains of conversion
chemistry materials that are mixed with intercalation chemistry
materials have a d.sub.50 of 6 nm. In some other examples, the
grains of conversion chemistry materials that are mixed with
intercalation chemistry materials have a d.sub.50 of 7 nm. In other
examples, the grains of conversion chemistry materials that are
mixed with intercalation chemistry materials have a d.sub.50 of 8
nm. In still other examples, the grains of conversion chemistry
materials that are mixed with intercalation chemistry materials
have a d.sub.50 of 9 nm. In yet other examples, the grains of
conversion chemistry materials that are mixed with intercalation
chemistry materials have a d.sub.50 of 10 nm. In some examples, the
grains of conversion chemistry materials that are mixed with
intercalation chemistry materials have a d.sub.50 of 11 nm. In some
other examples, the grains of conversion chemistry materials that
are mixed with intercalation chemistry materials have a d.sub.50 of
12 nm. In other examples, the grains of conversion chemistry
materials that are mixed with intercalation chemistry materials
have a d.sub.50 of 13 nm. In still other examples, the grains of
conversion chemistry materials that are mixed with intercalation
chemistry materials have a d.sub.50 of 14 nm. In yet other
examples, the grains of conversion chemistry materials that are
mixed with intercalation chemistry materials have a d.sub.50 of 15
nm. In some examples, the grains of conversion chemistry materials
that are mixed with intercalation chemistry materials have a
d.sub.50 of 16 nm. In some other examples, the grains of conversion
chemistry materials that are mixed with intercalation chemistry
materials have a d.sub.50 of 17 nm. In other examples, the grains
of conversion chemistry materials that are mixed with intercalation
chemistry materials have a d.sub.50 of 18 nm. In still other
examples, the grains of conversion chemistry materials that are
mixed with intercalation chemistry materials have a d.sub.50 of 19
nm. In yet other examples, the grains of conversion chemistry
materials that are mixed with intercalation chemistry materials
have a d.sub.50 of 20 nm. In some examples, the grains of
conversion chemistry materials that are mixed with intercalation
chemistry materials have a d.sub.50 of 21 nm. In some other
examples, the grains of conversion chemistry materials that are
mixed with intercalation chemistry materials have a d.sub.50 of 22
nm. In other examples, the grains of conversion chemistry materials
that are mixed with intercalation chemistry materials have a
d.sub.50 of 23 nm. In still other examples, the grains of
conversion chemistry materials that are mixed with intercalation
chemistry materials have a d.sub.50 of 24 nm. In yet other
examples, the grains of conversion chemistry materials that are
mixed with intercalation chemistry materials have a d.sub.50 of 25
nm. In some examples, the grains of conversion chemistry materials
that are mixed with intercalation chemistry materials have a
d.sub.50 of 26 nm. In some other examples, the grains of conversion
chemistry materials that are mixed with intercalation chemistry
materials have a d.sub.50 of 27 nm. In other examples, the grains
of conversion chemistry materials that are mixed with intercalation
chemistry materials have a d.sub.50 of 28 nm. In still other
examples, the grains of conversion chemistry materials that are
mixed with intercalation chemistry materials have a d.sub.50 of 29
nm. In yet other examples, the grains of conversion chemistry
materials that are mixed with intercalation chemistry materials
have a d.sub.50 of 30 nm.
Amounts of Conversion Chemistry and Intercalation Chemistry
Materials in Cathode
[0108] In some examples, the amount of intercalation chemistry
material that is mixed with the conversion chemistry material is
less than 30% w/w (by weight). In some examples, the amount of
intercalation chemistry material that is mixed with the conversion
chemistry material is present in the cathode at an amount of 29.5%
w/w. In other examples, the amount of intercalation chemistry
material that is mixed with the conversion chemistry material is
present in the cathode at an amount of 29.0% w/w. In certain
examples, the amount of intercalation chemistry material that is
mixed with the conversion chemistry material is present in the
cathode at an amount of 28.5% w/w. In other examples, the amount of
intercalation chemistry material that is mixed with the conversion
chemistry material is present in the cathode at an amount of 28.0%
w/w. In yet other examples, the amount of intercalation chemistry
material that is mixed with the conversion chemistry material is
present in the cathode at an amount of 27.5% w/w. In still other
examples, the amount of intercalation chemistry material that is
mixed with the conversion chemistry material is present in the
cathode at an amount of 27.0% w/w. In some examples, the amount of
intercalation chemistry material that is mixed with the conversion
chemistry material is present in the cathode at an amount of 26.5%
w/w. In other examples, the amount of intercalation chemistry
material that is mixed with the conversion chemistry material is
present in the cathode at an amount of 26.0% w/w. In certain
examples, the amount of intercalation chemistry material that is
mixed with the conversion chemistry material is present in the
cathode at an amount of 25.5% w/w. In other examples, the amount of
intercalation chemistry material that is mixed with the conversion
chemistry material is present in the cathode at an amount of 25.0%
w/w. In yet other examples, the amount of intercalation chemistry
material that is mixed with the conversion chemistry material is
present in the cathode at an amount of 24.5% w/w. In still other
examples, the amount of intercalation chemistry material that is
mixed with the conversion chemistry material is present in the
cathode at an amount of 24.0% w/w. In some examples, the amount of
intercalation chemistry material that is mixed with the conversion
chemistry material is present in the cathode at an amount of 23.5%
w/w. In other examples, the amount of intercalation chemistry
material that is mixed with the conversion chemistry material is
present in the cathode at an amount of 23.0% w/w. In certain
examples, the amount of intercalation chemistry material that is
mixed with the conversion chemistry material is present in the
cathode at an amount of 22.5% w/w. In other examples, the amount of
intercalation chemistry material that is mixed with the conversion
chemistry material is present in the cathode at an amount of 22.0%
w/w. In yet other examples, the amount of intercalation chemistry
material that is mixed with the conversion chemistry material is
present in the cathode at an amount of 21.5% w/w. In still other
examples, the amount of intercalation chemistry material that is
mixed with the conversion chemistry material is present in the
cathode at an amount of 21.0% w/w. In some examples, the amount of
intercalation chemistry material that is mixed with the conversion
chemistry material is present in the cathode at an amount of 20.5%
w/w. In other examples, the amount of intercalation chemistry
material that is mixed with the conversion chemistry material is
present in the cathode at an amount of 19.0% w/w. In certain
examples, the amount of intercalation chemistry material that is
mixed with the conversion chemistry material is present in the
cathode at an amount of 18.5% w/w. In other examples, the amount of
intercalation chemistry material that is mixed with the conversion
chemistry material is present in the cathode at an amount of 18.0%
w/w. In yet other examples, the amount of intercalation chemistry
material that is mixed with the conversion chemistry material is
present in the cathode at an amount of 17.5% w/w. In still other
examples, the amount of intercalation chemistry material that is
mixed with the conversion chemistry material is present in the
cathode at an amount of 17.0% w/w. In some examples, the amount of
intercalation chemistry material that is mixed with the conversion
chemistry material is present in the cathode at an amount of 16.5%
w/w. In other examples, the amount of intercalation chemistry
material that is mixed with the conversion chemistry material is
present in the cathode at an amount of 16.0% w/w. In certain
examples, the amount of intercalation chemistry material that is
mixed with the conversion chemistry material is present in the
cathode at an amount of 15.5% w/w. In other examples, the amount of
intercalation chemistry material that is mixed with the conversion
chemistry material is present in the cathode at an amount of 15.0%
w/w. In yet other examples, the amount of intercalation chemistry
material that is mixed with the conversion chemistry material is
present in the cathode at an amount of 15.5% w/w. In still other
examples, the amount of intercalation chemistry material that is
mixed with the conversion chemistry material is present in the
cathode at an amount of 15.0% w/w. In some examples, the amount of
intercalation chemistry material that is mixed with the conversion
chemistry material is present in the cathode at an amount of 14.5%
w/w. In other examples, the amount of intercalation chemistry
material that is mixed with the conversion chemistry material is
present in the cathode at an amount of 14.0% w/w. In certain
examples, the amount of intercalation chemistry material that is
mixed with the conversion chemistry material is present in the
cathode at an amount of 13.5% w/w. In other examples, the amount of
intercalation chemistry material that is mixed with the conversion
chemistry material is present in the cathode at an amount of 13.0%
w/w. In yet other examples, the amount of intercalation chemistry
material that is mixed with the conversion chemistry material is
present in the cathode at an amount of 12.5% w/w. In still other
examples, the amount of intercalation chemistry material that is
mixed with the conversion chemistry material is present in the
cathode at an amount of 12.0% w/w. In some examples, the amount of
intercalation chemistry material that is mixed with the conversion
chemistry material is present in the cathode at an amount of 11.5%
w/w. In other examples, the amount of intercalation chemistry
material that is mixed with the conversion chemistry material is
present in the cathode at an amount of 11.0% w/w. In certain
examples, the amount of intercalation chemistry material that is
mixed with the conversion chemistry material is present in the
cathode at an amount of 10.5% w/w. In other examples, the amount of
intercalation chemistry material that is mixed with the conversion
chemistry material is present in the cathode at an amount of 9.0%
w/w. In yet other examples, the amount of intercalation chemistry
material that is mixed with the conversion chemistry material is
present in the cathode at an amount of 9.5% w/w. In still other
examples, the amount of intercalation chemistry material that is
mixed with the conversion chemistry material is present in the
cathode at an amount of 8.0% w/w. In some examples, the amount of
intercalation chemistry material that is mixed with the conversion
chemistry material is present in the cathode at an amount of 8.5%
w/w. In other examples, the amount of intercalation chemistry
material that is mixed with the conversion chemistry material is
present in the cathode at an amount of 7.0% w/w. In certain
examples, the amount of intercalation chemistry material that is
mixed with the conversion chemistry material is present in the
cathode at an amount of 7.5% w/w. In other examples, the amount of
intercalation chemistry material that is mixed with the conversion
chemistry material is present in the cathode at an amount of 6.0%
w/w. In yet other examples, the amount of intercalation chemistry
material that is mixed with the conversion chemistry material is
present in the cathode at an amount of 6.5% w/w. In still other
examples, the amount of intercalation chemistry material that is
mixed with the conversion chemistry material is present in the
cathode at an amount of 6.0% w/w. In some examples, the amount of
intercalation chemistry material that is mixed with the conversion
chemistry material is present in the cathode at an amount of 5.5%
w/w. In other examples, the amount of intercalation chemistry
material that is mixed with the conversion chemistry material is
present in the cathode at an amount of 4.0% w/w. In certain
examples, the amount of intercalation chemistry material that is
mixed with the conversion chemistry material is present in the
cathode at an amount of 4.5% w/w. In other examples, the amount of
intercalation chemistry material that is mixed with the conversion
chemistry material is present in the cathode at an amount of 4.0%
w/w. In yet other examples, the amount of intercalation chemistry
material that is mixed with the conversion chemistry material is
present in the cathode at an amount of 3.5% w/w. In still other
examples, the amount of intercalation chemistry material that is
mixed with the conversion chemistry material is present in the
cathode at an amount of 3.0% w/w. In some examples, the amount of
intercalation chemistry material that is mixed with the conversion
chemistry material is present in the cathode at an amount of 2.5%
w/w. In other examples, the amount of intercalation chemistry
material that is mixed with the conversion chemistry material is
present in the cathode at an amount of 2.0% w/w. In certain
examples, the amount of intercalation chemistry material that is
mixed with the conversion chemistry material is present in the
cathode at an amount of 1.5% w/w. In other examples, the amount of
intercalation chemistry material that is mixed with the conversion
chemistry material is present in the cathode at an amount of 1.0%
w/w. In still other examples, the amount of intercalation chemistry
material that is mixed with the conversion chemistry material is
present in the cathode at an amount of 0.5% w/w.
[0109] In some examples, the conversion material is FeF.sub.3 or
NiF.sub.2 and the intercalation material is present in the cathode
at an amount of 10% w/w. In some examples, the conversion material
is FeF.sub.3 or NiF.sub.2 and the intercalation material is present
in the cathode at an amount of 5% w/w.
[0110] It is to be appreciated that embodiments of the disclosure
set forth herein provide numerous advantages over conventional
battery systems and methods. Among other things, with mixed
intercalation and conversion chemistry materials, the cathode
regions of battery cells can provide both high energy density and
operating flexibility. The relatively small amount of the
intercalation chemistry material at the cathode can provide
additional degrees of flexibility in battery design to meet
requirements of battery operation at low temperature or near its
voltage limits, without adding too much weight. For example, during
regenerative braking process of operating an electric vehicle, the
intercalation chemistry material absorbs electrical power when
voltage is too high for the conversion chemistry material. As
another example, when conversion chemistry material is operating
under conversion regime and the cell voltage is low, the
intercalation chemistry material can satisfy peak power demand. The
conversion chemistry material, which offers higher energy density
and capacity than the intercalation chemistry material, provides
energy at a steady voltage for other operation of electric motors.
There are other benefits as well.
EXAMPLES
Example 1
Positive Electrode Preparation
[0111] Positive electrodes were prepared by mixing and milling
either crystalline FeF.sub.3 or an 80:20 w/w mixture of crystalline
iron trifluoride (i.e., FeF.sub.3) and lithium titanate (LTO) with
carbon (C65 Conductive Carbon Black) and an Ethylene Propylene
Rubber binder (EPR). These positive electrodes were disposed onto a
liquid electrolyte including celgard membrane which was disposed on
and contacting a Li-metal anode. The celgard separator contained
the liquid electrolyte and physically separated the positive and
negative electrodes. The liquid electrolyte included ethylene
carbonate (EC) dimethylcarbonate (DMC) solvents in a 50:50 v/v
(EC:DMC) ratio with 1M LiPF.sub.6 salt. In some examples, the
electrochemical cells included only FeF.sub.3 as the positive
electrode active material. In some other examples, the
electrochemical cells included both FeF.sub.3 and LTO in an 80:20
w/w ratio as the positive electrode active material.
Example 2
Electrochemical Testing of Hybrid Positive Electrodes with
Comparison to Positive Electrodes Having Conversion Chemistry
Active Materials
[0112] FIG. 11 shows a high rate discharge initially after
assembling the electrochemical cell (i.e., 0.sup.th discharge). The
discharge was run at C/10 rate and at 50.degree. C. The plateau at
1.6V in the LTO-including sample shows that the positive electrode
with both FeF.sub.3 and LTO took a longer time during discharge to
reach the 1.5V floor. This example demonstrates that LTO, with a
lower operating voltage above the lowest conversion voltage for
FeF.sub.3 "railed," or prevented, the electrochemical cell from
dropping to 1.5V as soon as it would have in the absence of LTO
(i.e., in the electrochemical cell having only FeF.sub.3).
[0113] FIG. 12 shows the subsequent charging of the electrochemical
cells used in the experiment to generate the data in FIG. 11. The
initial plateau at 1.6V in the LTO-including sample shows that the
positive electrode with both FeF.sub.3 and LTO begins the charging
cycle at a higher voltage than the positive electrode with only
FeF.sub.3 active material. This example also demonstrates that LTO,
which has a lower operating voltage which is above the lowest
conversion voltage for FeF.sub.3, "railed" the electrochemical cell
from dropping to 1.5V as soon as it would have in the absence of
LTO (i.e., in the electrochemical cell having only FeF.sub.3).
Example 3
Electrochemical Testing of Hybrid Positive Electrodes with
Comparison to Positive Electrodes Having Conversion Chemistry
Active Materials
[0114] Electrochemical cells were prepared according to Example 1.
These electrochemical cells were analyzed at 50.degree. C. using
the following pulse cycle: An C/10 rate continuous discharge pulse,
followed by a rest to allow the cell voltage to equilibrate, and 1
minute current pulses of C/5, C/3, and C/2, each with a five (5)
minute rest period in between the discharge pulse. The cell Voltage
(V v. Li) as a function of Run Time (s) was observed and recorded
as FIGS. 13-18. The control samples only included FeF.sub.3 as the
positive electrode active material. The LTO samples included both
FeF.sub.3 and LTO (lithium titanate) in an 80:20 w/w ratio.
[0115] FIG. 13 shows the discharge voltage versus time near the end
of a discharge for two representative control cells with 100%
conversion chemistry, FeF.sub.3, cathodes compared to two
representative cells with a hybrid cathode: 80 wt % conversion
chemistry, FeF.sub.3, and 20 weight % intercalation chemistry, LTO.
The intercalation material has a discharge voltage between
1.55-1.64V. FIGS. 13 and 14 show that the hybrid cathode has
shallower voltage spikes during the current pulses and therefore
hits the voltage floor later than the cathode having only
conversion chemistry active materials. FIGS. 13 and 13 show that
the hybrid cathode was observed to have nearly 10% more capacity
and less degradation of the electrolyte, and thus a longer battery
cycle life.
[0116] FIG. 14 shows the electrochemical test using the same
conditions above but magnified (i.e., zoomed in) to show the last
discharge and only showing one representative cell from each batch
for clarity. Of particular note is the relative voltage spike near
39500 seconds indicated by the left arrow, and the shallow voltage
of discharge indicated by the second arrow, and the following
discharge. This example demonstrates that LTO, with a discharge
voltage above the lowest conversion voltage for FeF.sub.3 "railed,"
or prevented, the electrochemical cell from dropping to the lower
voltage than the cathode having only FeF.sub.3 achieved.
Example 4
Electrochemical Testing of Hybrid Positive Electrodes with
Comparison to Positive Electrodes Having Conversion Chemistry
Active Materials
[0117] FIG. 15 shows the electrochemical test using the same
conditions above. In this example, the data is analyzed to extract
the area-specific resistance (ASR.sub.dc) versus pulse cycle
throughout the discharge. As shown in FIG. 15, the cathode
including LTO and FeF.sub.3 was observed to have a lower ASR
throughout the discharge, particularly at the last pulse.
[0118] FIGS. 16-18 show additional electrochemical results using
the same conditions above but magnified (i.e., zoomed in) to show
the last discharge and only showing one representative cell from
each batch for clarity. This example demonstrates that LTO, with a
discharge voltage above the lowest conversion voltage for FeF.sub.3
"railed," or prevented, the electrochemical cell from dropping to
the lower voltage than the cathode having only FeF.sub.3
achieved.
Example 5
Hybrid Electrode Calculations for Hybrid Positive Electrodes with
Comparison to Positive Electrodes Having Either Only Conversion
Chemistry Active Materials or Only Intercalation Chemistry Active
Materials
[0119] To simulate how mixing cathode materials affects the voltage
response, an equivalent circuit model of the system was
constructed. There model included linear equations useful for
calculating a positive electrode voltage and three types of
components including: 1) Resistive elements which were used to
model ohmic resistance to either ionic or electronic transport;
Capacity elements which represented materials which store charge
electrochemically and have both an open circuit voltage and a
capacity, and Resistor/capacitor pairs which model charge-transfer
effects where exchange current is limited by reaction kinetics. The
components which comprised the conversion and intercalation
materials were arranged in discrete layers to represent the hybrid
chemistry electrodes. The characteristics of these components may
vary with temperature, state of charge, direction of load current,
magnitude of load current, and various other factors. The
characteristics of these components may be set to simulate any of
the conversion or intercalation chemistries mentioned in this
document. To simulate the voltage response of the battery, a
controlled current load is attached to the terminals of the model.
Using the known load current, the cell voltage may be determined
using circuit analysis techniques.
[0120] Materials--
[0121] In this example, a total of the three cathode layers were
used. There are two layers of conversion material (FeF.sub.3) and
one layer of intercalation material (LTO or LCO). The layer of
intercalation material was placed closest to the anode of the
battery. It is to be appreciated that the number and type of
materials selected and their respective capacity may be adjusted as
needed to simulate the desired combination.
[0122] Results--
[0123] The power demand profile shown in FIG. 19 shows the
controlled load stimulus which generates the voltage response in
FIG. 20. FIG. 20 shows three sets of simulation results. The first
shows the voltage response to the power demand from a battery with
only conversion chemistry active materials in the positive
electrode. The second shows the voltage response to the power
demand from a battery with both intercalation chemistry active
materials mixed with conversion chemistry active materials, in a
95:5 w/w ratio, in the positive electrode. The third shows the
voltage response to the power demand from a battery with only
intercalation material in the positive electrode.
[0124] This Example shows, in FIG. 20, that the voltage of the
mixed chemistry battery does not fall below the lower voltage
threshold during a high power demand event at low state of
charge.
[0125] The power demand profile shown in FIG. 21 shows the
controlled load stimulus which generates the voltage response in
FIG. 22. FIG. 22 shows three sets of simulation results. The first
shows the voltage response to the power demand from a battery with
only conversion chemistry active materials in the positive
electrode. The second shows the voltage response to the power
demand from a battery with both intercalation chemistry active
materials mixed with conversion chemistry active materials, in a
90:10 w/w ratio, in the positive electrode. The third shows the
voltage response to the power demand from a battery with only
intercalation material in the positive electrode.
[0126] This Example shows, in FIG. 222, that the voltage of the
mixed chemistry battery does not exceed the upper voltage cutoff
during a high power regenerative brake event at high state of
charge.
[0127] While the above is a full description of the specific
embodiments, various modifications, alternative constructions and
equivalents may be used. Therefore, the above description and
illustrations should not be taken as limiting the scope of the
present invention which is defined by the appended claims.
* * * * *