U.S. patent application number 14/550884 was filed with the patent office on 2015-06-04 for fluoride ion electrochemical cell.
This patent application is currently assigned to California Institute of Technology. The applicant listed for this patent is California Institute of Technology, Centre National De La Recherche Scientifique (C.N.R.S.). Invention is credited to Rachid YAZAMI.
Application Number | 20150155598 14/550884 |
Document ID | / |
Family ID | 40295687 |
Filed Date | 2015-06-04 |
United States Patent
Application |
20150155598 |
Kind Code |
A1 |
YAZAMI; Rachid |
June 4, 2015 |
Fluoride Ion Electrochemical Cell
Abstract
Electrochemical cells of the present invention are versatile and
include primary and secondary cells useful for a range of important
applications including use in portable electronic devices.
Electrochemical cells of the present invention also exhibit
enhanced safety and stability relative to conventional state of the
art primary lithium batteries and lithium ion secondary batteries.
For example, electrochemical cells of the present invention include
secondary electrochemical cells using anion charge carriers capable
of accommodation by positive and negative electrodes comprising
anion host materials, which entirely eliminate the need for
metallic lithium or dissolved lithium ion in these systems.
Inventors: |
YAZAMI; Rachid; (Singapore,
SG) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
California Institute of Technology
Centre National De La Recherche Scientifique (C.N.R.S.) |
Pasadena
Paris |
CA |
US
FR |
|
|
Assignee: |
California Institute of
Technology
Pasadena
CA
Centre National De La Recherche Scientifique (C.N.R.S.)
Paris
|
Family ID: |
40295687 |
Appl. No.: |
14/550884 |
Filed: |
November 21, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13739487 |
Jan 11, 2013 |
8968921 |
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14550884 |
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11681493 |
Mar 2, 2007 |
8377586 |
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13739487 |
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11677541 |
Feb 21, 2007 |
8232007 |
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11681493 |
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11422564 |
Jun 6, 2006 |
7563542 |
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11677541 |
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11253360 |
Oct 18, 2005 |
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11422564 |
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11675308 |
Feb 15, 2007 |
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11677541 |
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PCT/US07/62243 |
Feb 15, 2007 |
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11675308 |
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11560570 |
Nov 16, 2006 |
7794880 |
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11681493 |
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PCT/US07/63094 |
Mar 1, 2007 |
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11681493 |
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60779054 |
Mar 3, 2006 |
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60897310 |
Jan 25, 2007 |
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60900409 |
Feb 9, 2007 |
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60724084 |
Oct 5, 2005 |
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60724084 |
Oct 5, 2005 |
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60774262 |
Feb 16, 2006 |
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60784957 |
Mar 21, 2006 |
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60784960 |
Mar 20, 2006 |
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60774262 |
Feb 16, 2006 |
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60784957 |
Mar 21, 2006 |
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60784960 |
Mar 20, 2006 |
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60775110 |
Feb 21, 2006 |
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60775559 |
Feb 22, 2006 |
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60900409 |
Feb 9, 2007 |
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60737186 |
Nov 16, 2005 |
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60775110 |
Feb 21, 2006 |
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60775559 |
Feb 22, 2006 |
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Current U.S.
Class: |
429/200 ;
429/199 |
Current CPC
Class: |
H01M 4/606 20130101;
H01M 10/0561 20130101; H01M 4/60 20130101; H01M 6/04 20130101; H01M
2300/0002 20130101; H01M 2300/0017 20130101; H01M 4/38 20130101;
H01M 10/0567 20130101; H01M 10/22 20130101; H01M 4/5835 20130101;
H01M 10/36 20130101; Y02E 60/10 20130101; H01M 4/582 20130101; H01M
10/26 20130101; H01M 6/045 20130101; H01M 6/166 20130101; H01M
10/0568 20130101; H01M 10/08 20130101; H01M 10/04 20130101; H01M
4/608 20130101; H01M 4/604 20130101; H01M 4/583 20130101 |
International
Class: |
H01M 10/0567 20060101
H01M010/0567; H01M 10/08 20060101 H01M010/08; H01M 10/26 20060101
H01M010/26; H01M 10/22 20060101 H01M010/22; H01M 4/583 20060101
H01M004/583; H01M 10/0561 20060101 H01M010/0561 |
Claims
1. An electrochemical cell comprising: a positive electrode; a
negative electrode; and liquid phase electrolyte provided between
said positive electrode and said negative electrode; said
electrolyte capable of conducting anion charge carriers; said
liquid phase electrolyte comprising a source of fluoride ions
(F.sup.-) dissolved in a solvent. wherein said positive electrode
and negative electrode reversibly exchange said anion charge
carriers with said electrolyte during charging or discharging of
said electrochemical cell; wherein said anion charge carriers are
said fluoride ions.
2. (canceled)
3. The electrochemical cell of claim 1 wherein said electrolyte
comprises a solvent and a fluoride salt, wherein said fluoride salt
is at least partially present in a dissolved state in said
electrolyte, thereby generating said fluoride ions in said
electrolyte.
4. The electrochemical cell of claim 3 wherein said fluoride salt
has the formula MF.sub.n, wherein M is a metal, and n is an integer
greater than 0.
5. The electrochemical cell of claim 4 wherein M is an alkali metal
or an alkaline earth metal.
6. The electrochemical cell of claim 4 wherein M is a metal other
than lithium.
7. The electrochemical cell of claim 4 wherein M is Na, K, or
Rb.
8. The electrochemical cell of claim 1 wherein said anion charge
carriers are selected from the group consisting of: BF.sub.4.sup.-,
PF.sub.6.sup.-, AsF.sub.6.sup.-, SbF.sub.6.sup.-, BiF.sub.6.sup.-,
AlF.sub.4.sup.-, GaF.sub.4.sup.-, InF.sub.4.sup.-, TlF.sub.4.sup.-,
SiF.sub.5.sup.-, GeF.sub.5.sup.-, SnF.sub.5.sup.-, PbF.sub.5.sup.-,
SF.sub.7.sup.-, IF.sub.6.sup.-, ClO.sub.4.sup.-,
CF.sub.3SO.sub.3.sup.-, (CF.sub.3SO.sub.2).sub.2N.sup.- and
C.sub.4F.sub.9SO.sub.3.sup.-
9. (canceled)
10. The electrochemical cell of claim 1 wherein said electrolyte
further comprises an anion receptor.
11. The electrochemical cell of claim 3 wherein said electrolyte
further comprises a fluoride ion anion receptor capable of
coordinating fluoride ions from said fluoride salt.
12. The electrochemical cell of claim 1 wherein said electrolyte
further comprises a cation receptor capable of coordinating metal
ions from said fluoride salt.
13. The electrochemical cell of claim 1 wherein said electrolyte is
an aqueous electrolyte.
14. The electrochemical cell of claim 1 wherein said electrolyte is
a nonaqueous electrolyte.
15. The electrochemical cell of claim 1 wherein said negative
electrode is a fluoride ion host material.
16. The electrochemical cell of claim 15 wherein said fluoride ion
host material of said negative electrode is a fluoride
compound.
17. The electrochemical cell of claim 15 wherein said fluoride ion
host material of said negative electrode is selected from the group
consisting of: LaF.sub.x, CaF.sub.x, AlF.sub.x, EuF.sub.x,
LiC.sub.6, Li.sub.xSi, Li.sub.xGe, Li.sub.x(CoTiSn), SnF.sub.x,
InF.sub.x, VF.sub.x, CdF.sub.x, CrF.sub.x, FeF.sub.x, ZnF.sub.x,
GaF.sub.x, TiF.sub.x, NbF.sub.x, MnF.sub.x, YbF.sub.x, ZrF.sub.x,
SmF.sub.x, LaF.sub.x and CeF.sub.x,
18. The electrochemical cell of claim 15 wherein said fluoride ion
host material of said negative electrode is a polymer selected from
the group consisting of: polyacetylene, polyaniline, polypyrrol,
polythiophene and polyparaphenylene.
19. The electrochemical cell of claim 15 wherein said negative
electrode has a standard electrode potential less than or equal to
-1 V.
20. The electrochemical cell of claim 15 wherein said negative
electrode has a standard electrode potential less than or equal to
-2 V.
21. The electrochemical cell of claim 1 wherein said electrolyte
does not comprise lithium ions.
22. The electrochemical cell of claim 1 wherein said electrolyte
comprises a fluoride salt dissolved in said solvent.
23. The electrochemical cell of claim 1 wherein said positive
electrode is a fluoride ion host material.
24. The electrochemical cell of claim 23 wherein said fluoride ion
host material of said positive electrode is an intercalation host
material capable of accommodating said fluoride ions so as to
generate a fluoride ion intercalation compound.
25. The electrochemical cell of claim 23 wherein said fluoride ion
host material of said positive electrode is a fluoride
compound.
26. The electrochemical cell of claim 25 wherein said fluoride ion
host material of said positive electrode is a subfluorinated
carbonaceous material having a formula CF.sub.x, wherein x is the
average atomic ratio of fluorine atoms to carbon atoms and is
selected from the range of 0.3 to 1.0; and wherein said
carbonaceous material is selected from the group consisting of
graphite, coke, multiwalled carbon nanotubes, multi-layered carbon
nanofibers, multi-layered carbon nanoparticles, carbon nanowhiskers
and carbon nanorods.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 13/739,487, filed on Jan. 11, 2013, which is a continuation of
Ser. No. 11/681,493, filed on Mar. 2, 2007 which claims priority
under 35 U.S.C. 119(e) to U.S. provisional Patent Application
60/779,054 filed Mar. 3, 2006, U.S. provisional Patent Application
No. 60/897,310, filed Jan. 25, 2007, and U.S. Provisional
Application No. 60/900,409, filed Feb. 9, 2007. Each of these
applications is incorporated by reference in its entirety to the
extent not inconsistent with the disclosure herein.
[0002] U.S. application Ser. No. 11/681,493 is also a
continuation-in-part of U.S. application Ser. No. 11/677,541, filed
Feb. 21, 2007, which is a continuation in part of U.S. application
Ser. No. 11/422,564, filed Jun. 6, 2006, which claims the benefit
of U.S. Provisional Application 60/724,084, filed Oct. 5, 2005 and
is a continuation in part of U.S. application Ser. No. 11/253,360
filed Oct. 18, 2005, which also claims the benefit of U.S.
Provisional Application 60/724,084, filed Oct. 5, 2005. Ser. No.
11/677,541 is also a continuation in part of U.S. application Ser.
No. 11/675,308 and International Application PCT/US2007/62243, both
filed Feb. 15, 2007, both of which claim the benefit of U.S.
Provisional Applications 60/774,262, filed Feb. 16, 2006,
60/784,957, filed Mar. 21, 2006 and 60/784,960, filed Mar. 20,
2006. Ser. No. 11/677,541 also claims the benefit of U.S.
Provisional Application Nos. 60/775,110, filed Feb. 21, 2006,
60/775,559, filed Feb. 22, 2006, and U.S. Provisional Application
No. 60/900,409 filed Feb. 9, 2007. Each of these applications is
incorporated by reference in its entirety to the extent not
inconsistent with the disclosure herein.
[0003] U.S. application Ser. No. 11/681,493 is also a
continuation-in-part of U.S. application Ser. No. 11/560,570, filed
Nov. 16, 2006, which claims priority from U.S. Provisional
Application Nos. 60/737,186, 60/775,110, 60/775,559 filed Nov. 16,
2005, Feb. 21, 2006 and Feb. 22, 2006, respectively. Each of these
applications is incorporated by reference in its entirety to the
extent not inconsistent with the disclosure herein.
[0004] U.S. application Ser. No. 11/681,493 is also a
continuation-in-part of PCT International Application No.
PCT/US2007/063094, filed on Mar. 1, 2007.
BACKGROUND OF INVENTION
[0005] Over the last few decades revolutionary advances have been
made in electrochemical storage and conversion devices expanding
the capabilities of these systems in a variety of fields including
portable electronic devices, air and space craft technologies, and
biomedical instrumentation. Current state of the art
electrochemical storage and conversion devices have designs and
performance attributes that are specifically engineered to provide
compatibility with a diverse range of application requirements and
operating environments. For example, advanced electrochemical
storage systems have been developed spanning the range from high
energy density batteries exhibiting very low self discharge rates
and high discharge reliability for implanted medical devices to
inexpensive, light weight rechargeable batteries providing long
runtimes for a wide range of portable electronic devices to high
capacity batteries for military and aerospace applications capable
of providing extremely high discharge rates over short time
periods.
[0006] Despite the development and widespread adoption of this
diverse suite of advanced electrochemical storage and conversion
systems, significant pressure continues to stimulate research to
expand the functionality of these systems, thereby enabling an even
wider range of device applications. Large growth in the demand for
high power portable electronic products, for example, has created
enormous interest in developing safe, light weight primary and
secondary batteries providing higher energy densities. In addition,
the demand for miniaturization in the field of consumer electronics
and instrumentation continues to stimulate research into novel
design and material strategies for reducing the sizes, masses and
form factors of high performance batteries. Further, continued
development in the fields of electric vehicles and aerospace
engineering has also created a need for mechanically robust, high
reliability, high energy density and high power density batteries
capable of good device performance in a useful range of operating
environments.
[0007] Many recent advances in electrochemical storage and
conversion technology are directly attributable to discovery and
integration of new materials for battery components. Lithium
battery technology, for example, continues to rapidly develop, at
least in part, due to the discovery of novel electrode and
electrolyte materials for these systems. From the pioneering
discovery and optimization of intercalation host materials for
positive electrodes, such as fluorinated carbon materials and
nanostructured transition metal oxides, to the development of high
performance nonaqueous electrolytes, the implementation of novel
materials strategies for lithium battery systems have
revolutionized their design and performance capabilities.
Furthermore, development of intercalation host materials for
negative electrodes has led to the discovery and commercial
implementation of lithium ion based secondary batteries exhibiting
high capacity, good stability and useful cycle life. As a result of
these advances, lithium based battery technology is currently
widely adopted for use in a range of important applications
including primary and secondary electrochemical cells for portable
electronic systems.
[0008] Commercial primary lithium battery systems typically utilize
a lithium metal negative electrode for generating lithium ions
which during discharge are transported through a liquid phase or
solid phase electrolyte and undergo intercalation reaction at a
positive electrode comprising an intercalation host material. Dual
intercalation lithium ion secondary batteries have also been
developed, wherein lithium metal is replaced with a lithium ion
intercalation host material for the negative electrode, such as
carbons (e.g., graphite, cokes etc.), metal oxides, metal nitrides
and metal phosphides. Simultaneous lithium ion insertion and
de-insertion reactions allow lithium ions to migrate between the
positive and negative intercalation electrodes during discharge and
charging. Incorporation of a lithium ion intercalation host
material for the negative electrode has the significant advantage
of avoiding the use of metallic lithium which is susceptible to
safety problems upon recharging attributable to the highly reactive
nature and non-epitaxial deposition properties of lithium.
[0009] The element lithium has a unique combination of properties
that make it attractive for use in an electrochemical cell. First,
it is the lightest metal in the periodic table having an atomic
mass of 6.94 AMU. Second, lithium has a very low electrochemical
oxidation/reduction potential (i.e.,-3.045 V vs. NHE (normal
hydrogen reference electrode). This unique combination of
properties enables lithium based electrochemical cells to have very
high specific capacities. Advances in materials strategies and
electrochemical cell designs for lithium battery technology have
realized electrochemical cells capable of providing useful device
performance including: (i) high cell voltages (e.g. up to about 3.8
V), (ii) substantially constant (e.g., flat) discharge profiles,
(iii) long shelf-life (e.g., up to 10 years), and (iv)
compatibility with a range of operating temperatures (e.g., -20 to
60 degrees Celsius). As a result of these beneficial
characteristics, primary lithium batteries are widely used as power
sources in a range of portable electronic devices and in other
important device applications including, electronics, information
technology, communication, biomedical engineering, sensing,
military, and lighting.
[0010] State of the art lithium ion secondary batteries provide
excellent charge-discharge characteristics, and thus, have also
been widely adopted as power sources in portable electronic
devices, such as cellular telephones and portable computers. U.S.
Pat. Nos. 6,852,446, 6,306,540, 6,489,055, and "Lithium Batteries
Science and Technology" edited by Gholam-Abbas Nazri and
Gianfranceo Pistoia, Kluer Academic Publishers, 2004, are directed
to lithium and lithium ion battery systems which are hereby
incorporated by reference in their entireties.
[0011] As noted above, lithium metal is extremely reactive,
particularly with water and many organic solvents, and this
attribute necessitates use of an intercalation host material for
the negative electrode in secondary lithium based electrochemical
cells. Substantial research in this field has resulted in a range
of useful intercalation host materials for these systems, such as
LiC.sub.6, Li.sub.xSi, Li.sub.xSn and Li.sub.x(CoSnTi). Use of an
intercalation host material for the negative electrode, however,
inevitably results in a cell voltage that is lower by an amount
corresponding to the free energy of insertion/dissolution of
lithium in the intercalation electrode. As a result, conventional
state of the art dual intercalation lithium ion electrochemical
cells are currently limited to providing average operating voltages
less than or equal to about 4 Volts. This requirement on the
composition of the negative electrode also results in substantial
loss in the specific energies achievable in these systems. Further,
incorporation of an intercalation host material for the negative
electrode does not entirely eliminate safety risks. Charging these
lithium ion battery systems, for example, must be carried out under
very controlled conditions to avoid overcharging or heating that
can result in decomposition of the positive electrode. Further,
unwanted side reactions involving lithium ion can occur in these
systems resulting in the formation of reactive metallic lithium
that implicate significant safety concerns. During charging at high
rates or at low temperatures, lithium deposition results in
dendrides formation that may grow across the separator and cause an
internal short-circuit within the cell, generating heat, pressure
and possible fire from combustion of the organic electrolyte and
reaction of metallic lithium with air oxygen and moisture.
[0012] Dual-carbon cells have also been developed that utilize
lithium insertion reactions for electrochemical storage, wherein
anions and cations generated by dissolution of an appropriate
electrolyte salt provide the source of charge stored in the
electrodes. During charging of these systems, cations of the
electrolyte, such as lithium ion (Li.sup.+), undergo insertion
reaction at a negative electrode comprising a carbonaceous cation
host material, and anions of the electrolyte, such as
PF.sub.6.sup.-, undergo insertion reaction at a positive electrode
carbonaceous anion host material. During discharge, the insertion
reactions are reversed resulting in release of cations and anions
from positive and negative electrodes, respectively. State of the
art dual-carbon cells are unable to provide energy densities as
large as those provided by lithium ion cells, however, due to
practical limitations on the salt concentrations obtainable in
these systems. In addition, some dual-carbon cells are susceptible
to significant losses in capacity after cycling due to stresses
imparted by insertion and de-insertion of polyatomic anion charge
carriers such as PF.sub.6.sup.-. Further, dual-carbon cells are
limited with respect to the discharge and charging rates
attainable, and many of these system utilize electrolytes comprises
lithium salts, which can raise safety issues under some operating
conditions. Dual carbon cells are described in U.S. Pat. Nos.
4,830,938; 4,865,931; 5,518,836; and 5,532,083, and in "Energy and
Capacity Projections for Practical Dual-Graphite Cells", J. R. Dahn
and J. A. Seel, Journal of the Electrochemical Society, 147 (3)
899-901 (2000), which are hereby incorporated by reference to the
extent not inconsistent with the present disclosure.
[0013] A battery consists of a positive electrode (cathode during
discharge), a negative electrode (anode during discharge) and an
electrolyte. The electrolyte contains ionic species that are the
charge carriers. Electrolytes in batteries can be of several
different types: (1) pure cation conductors (e.g., beta Alumina
conducts with Na.sup.+ only); (2) pure anion conductors (e.g., high
temperature ceramics conduct with O.sup.- or O.sup.2- anions only);
and (3) mixed ionic conductors: (e.g., some Alkaline batteries use
a KOH aqueous solution that conducts with both OH.sup.- and
K.sup.+, whereas some lithium ion batteries use an organic solution
of LiPF.sub.6 that conducts with both Li.sup.+ and PF.sub.6.sup.-).
During charge and discharge electrodes exchange ions with
electrolyte and electrons with an external circuit (a load or a
charger).
[0014] There are two types of electrode reactions.
1. Cation based electrode reactions: In these reactions, the
electrode captures or releases a cation Y.sup.+ from electrolyte
and an electron from the external circuit:
Electrode+Y.sup.+e.sup.-.fwdarw.Electrode(Y).
Examples of cation based electrode reactions include: (i) carbon
anode in a lithium ion battery:
6C+Li.sup.++e.sup.-.fwdarw.LiC.sub.6 (charge); (ii) lithium cobalt
oxide cathode in a lithium ion battery:
2Li.sub.0.5CoO.sub.2+Li.sup.++e.sup.-.fwdarw.2LiCoO.sub.2
(discharge); (iii) Ni(OH).sub.2 cathode in rechargeable alkaline
batteries: Ni(OH).sub.2.fwdarw.NiOOH+H.sup.++e.sup.- (charge); (iv)
MnO.sub.2 in saline Zn/MnO.sub.2 primary batteries:
MnO.sub.2+H.sup.++e.sup.-.fwdarw.HMnO.sub.2 (discharge). 2. Anion
based electrode reactions: In these reactions, the electrode
captures or releases an anion X.sup.- from electrolyte and an
electron from the external circuit:
Electrode+X.sup.-.fwdarw.Electrode(X)+e.sup.-
Examples of anion based electrode reactions include: (i) Cadmium
anode in the Nickel-Cadmium alkaline battery:
Cd(OH).sub.2+2e.sup.-.fwdarw.Cd+2OH.sup.- (charge); and (ii)
Magnesium alloy anode in the magnesium primary batteries:
Mg+2OH.sup.-.fwdarw.Mg(OH).sub.2+2e.sup.- (discharge).
[0015] Existing batteries are either of pure cation-type or mixed
ion-type chemistries. To Applicants knowledge there are currently
no known batteries having pure anion-type chemistry. Example of
pure cation-type and mixed ion-type batteries are provided
below:
1. Pure cation-type of battery: Lithium ion batteries are an
example of pure cation-type chemistry. The electrode half reactions
and cell reactions for lithium ion batteries are: [0016] Carbon
anode:
[0016] 6C+Li.sup.++e.sup.-LiC.sub.6 (charge) [0017] lithium cobalt
oxide cathode:
[0017] 2Li.sub.0.5CoO.sub.2+Li.sup.++e.sup.-.fwdarw.2LiCoO.sub.2
(discharge) [0018] cell reaction:
[0018] 2LiCoO.sub.2+6C.fwdarw.2Li.sub.0.5CoO.sub.2+LiC.sub.6
(charge)
2Li.sub.0.5CoO.sub.2+LiC.sub.6.fwdarw.2LiCoO.sub.2+6C
(discharge)
2. Mixed ion-type of battery: A Nickel/cadmium alkaline battery is
an example of a mixed ion-type of battery. The electrode half
reactions and cell reactions for a Nickel/cadmium alkaline battery
are provided below: [0019] Ni(OH).sub.2 cathode (cation-type):
[0019] Ni(OH).sub.2.fwdarw.NiOOH+H.sup.++e.sup.- (charge) [0020]
Cadmium anode (anion-type):
[0020] Cd(OH).sub.2+2e.sup.-.fwdarw.Cd+2OH.sup.- (charge) [0021]
Cell reaction:
[0021] Cd(OH).sub.2+2Ni(OH).sub.2.fwdarw.Cd+2NiOOH+2H.sub.2O
(charge)
Cd+2NiOOH+2H.sub.2O.fwdarw.Cd(OH).sub.2+2Ni(OH).sub.2
(discharge)
A Zn/MnO.sub.2 battery is an example of a mixed ion-type of
battery. The electrode half reactions and cell reactions for a
Zn/MnO.sub.2 battery are provided below: [0022] Zn anode
(anion-type):
[0022] Zn+2OH.sup.-.fwdarw.ZnO+H.sub.2O+2e.sup.- (discharge) [0023]
MnO.sub.2 cathode (cation-type)
[0023] MnO.sub.2+H.sup.++e.sup.-HMnO.sub.2 (discharge) [0024] Cell
reaction:
[0024] Zn+2MnO.sub.2+H.sub.2O.fwdarw.ZnO+2HMnO.sub.2
(discharge)
[0025] As will be clear from the foregoing, there exists a need in
the art for secondary electrochemical cells for a range of
important device application including the rapidly increasing
demand for high performance portable electronics. Specifically,
secondary electrochemical cells are needed that are capable of
providing useful cell voltages, specific capacities and cycle life,
while at the same time exhibiting good stability and safety. A need
exists for alternative insertion/intercalation based
electrochemical cells that eliminate or reduce safety issues
inherent to the use of lithium in primary and secondary battery
systems.
SUMMARY OF THE INVENTION
[0026] The present invention provides electrochemical cells capable
of good electrical power source performance, particularly high
specific energies, useful discharge rate capabilities and good
cycle life. Electrochemical cells of the present invention are
versatile and include primary and secondary cells useful for a
range of important applications including use in portable
electronic devices. Electrochemical cells of the present invention
also exhibit enhanced safety and stability relative to conventional
state of the art primary lithium batteries and lithium ion
secondary batteries. For example, electrochemical cells of the
present invention include secondary anionic electrochemical cells
using anion charge carriers capable of accommodation by positive
and negative electrodes comprising anion host materials, which
entirely eliminate the need for metallic lithium or dissolved
lithium ion in these systems.
[0027] The present invention provides novel active electrode
materials strategies, electrolyte compositions and electrochemical
cell designs enabling a fundamentally new class of primary and
secondary electrochemical cells. Anion charge carrier host
materials for positive and negative electrodes and high performance
electrolytes are provided that enable a new electrochemical cell
platform capable of achieving useful performance attributes, such
as specific energies higher than that in conventional state of the
art lithium ion batteries. In an embodiment, for example, the
present invention provides combinations of different anion charge
carrier host materials for positive and negative electrodes that
enable secondary electrochemical cells capable of exhibiting cell
voltages greater than or equal to about 3.5 V. In addition,
positive and negative electrode materials combinations of the
present invention enable secondary electrochemical cells having a
large cycle life and exhibiting good discharge stability upon
cycling. Further, aqueous and nonaqueous electrolyte compositions
are provided that provide synergistic performance enhancements
important for improving device performance, stability and safety at
high cell voltages. For example, the present invention provides
high performance electrolytes having anion receptors and/or cation
receptors compatible with anion charge carrier active electrode
host materials that provide secondary cells capable of stable
discharge rates at high cell voltages.
[0028] In an aspect, the present invention provides an anionic
electrochemical cell utilizing an anion charge carrier capable of
accommodation by positive and negative electrodes comprising anion
host materials. This aspect of the present invention includes both
primary and secondary electrochemical cells. In an embodiment, an
electrochemical cell of this aspect of the present invention
comprises a positive electrode; a negative electrode; and an
electrolyte provided between the positive electrode and the
negative electrode, wherein the electrolyte is capable of
conducting anion charge carriers. The positive electrode and
negative electrode of this embodiment comprise different anion host
materials that reversibly exchange anion charge carriers with the
electrolyte during charging or discharging of the electrochemical
cell. In the context of this description, the term "exchange"
refers to release or accommodation of anion charge carriers at the
electrodes via oxidation and reduction reactions during discharge
or charging of the electrochemical cell. In this context,
"accommodation" of anion charge carriers includes capture of anion
charge carriers by the host material, insertion of anion charge
carriers into the host material, intercalation of anion charge
carriers into the host material and/or chemical reaction of anion
charge carriers with the host material. Accommodation includes
alloy formation chemical reactions, surface chemical reactions with
the host material and/or bulk chemical reactions with the host
material.
[0029] During discharge, reduction half reactions occurring at the
positive electrode result in release of anion charge carriers from
the positive electrode to the electrolyte, and oxidation half
reactions occurring at the negative electrode result in
accommodation of anion charge carriers by the negative electrode.
In these embodiments, therefore, anion charge carriers are released
from the positive electrode, migrate through the electrolyte and
are accommodated by the negative electrode during discharge of the
electrochemical cell. This kinetic process is reversed during
charging in secondary electrochemical cells of the present
invention. During charging in these embodiments, therefore,
reduction half reactions occurring at the negative electrode result
in release of anion charge carriers to the electrolyte, and
oxidation half reactions occurring at the positive electrode result
in accommodation of anion charge carriers from the electrolyte to
the positive electrode. Accordingly, simultaneous release and
accommodation of anion charge carriers during discharge and
charging of the electrochemical cell occurs as anion charge
carriers are transported through the electrolyte and electrons are
transported through an external circuit connecting positive and
negative electrodes.
[0030] Choice of the composition and phase of electrode host
materials, electrolyte and anion charge carriers in this aspect of
the invention is important in the present invention for accessing
useful electrochemical cell configurations. First, selection of the
compositions of the anion host materials for positive and negative
electrodes and the anion charge carrier determines, at least in
part, the cell voltage of the electrochemical cell. It is
beneficial in some embodiments, therefore, to select an anion host
material providing a sufficiently low standard electrode potential
at the negative electrode and to select an anion host material
providing a sufficiently high standard electrode potential at the
positive electrode so as to result in a cell voltage useful for a
given application. Second, selection of the compositions of the
anion host materials for positive and negative electrodes,
electrolyte and the anion charge carrier establishes the kinetics
at the electrode, and thus determines the discharge rate
capabilities of the electrochemical cell. Third, use of electrode
host materials, electrolyte and anion charge carriers that do not
result in fundamental structural changes or degradation at the
positive and negative electrodes during charging and discharge is
beneficial for secondary electrochemical cells exhibiting good
cycling performance.
[0031] In an embodiment of this aspect, the present invention
provides fluoride ion primary and secondary electrochemical cells
having fluoride ions (F.sup.-1) as the anion charge carriers.
Electrochemical cell utilizing fluoride ion charge carriers of the
present invention are referred to as fluoride ion electrochemical
cells. Use of fluoride ion charge carriers in electrochemical cells
of the present invention provides a number of benefits. First, the
low atomic mass (18.998 AMU), high electron affinity (-328 kJ
mol.sup.-1) of fluorine and about 6V redox voltage stability window
(from -3.03V vs. NHE to +2.87V vs. NHE) of the fluoride ion
(F.sup.-) results in electrochemical cells having high voltage,
high energy densities and high specific capacities. Second,
fluoride ion has a small atomic radius and, thus, can participate
in reversible insertion and/or intercalation reactions in many
electrode host materials that do not result in significant
degradation or significant structural deformation of the electrode
host material upon cycling in secondary electrochemical cells. This
property results in secondary fluoride ion electrochemical cells
having a large cycle life (e.g., greater than or equal to about 500
cycles). Third, fluoride ion is stable with respect to
decomposition at electrode surfaces for a useful range of voltages
(-3.03V vs. NHE to +2.87V vs. NHE), thereby providing enhanced
performance stability and safety of electrochemical cells. Fourth,
a significant number of fluoride ion host materials are available
for positive electrodes and negative electrodes that provide
electrochemical cells having large specific capacities and cell
voltages.
[0032] As will be evident to one of skill in the art, the present
invention includes, however, a wide range of anionic
electrochemical cell configurations having anion charge carriers
other than fluoride ions, including but not limited to:
BF.sub.4.sup.-, PF.sub.6.sup.-, AsF.sub.6.sup.-, SbF.sub.6.sup.-,
BiF.sub.6.sup.-, AlF.sub.4.sup.-, GaF.sub.4.sup.-, InF.sub.4.sup.-,
TlF.sub.4.sup.-, SiF.sub.5.sup.-, GeF.sub.5.sup.-, SnF.sub.5.sup.-,
PbF.sub.5.sup.-, SF.sub.7.sup.-, IF.sub.6.sup.-, ClO.sub.4.sup.-,
CF.sub.3SO.sub.3.sup.-, (CF.sub.3SO.sub.2).sub.2N.sup.- and
C.sub.4F.sub.9SO.sub.3.sup.- Other anion charge carriers useful in
electrochemical cells of the present invention include those having
the formula: C.sub.nF.sub.2n+1BF.sub.3.sup.-1; wherein n is an
integer greater than 1. Use of anion charge carriers other than
fluoride ion requires incorporation of suitable host materials for
positive and negative electrodes capable of accommodation of the
anion charge carrier during discharge and charging, and providing a
desired cell voltage and specific capacity. In an embodiment, the
anion charge carrier is an anion other than OH.sup.- and
HSO.sub.4.sup.-, or SO.sub.4.sup.2-.
[0033] In an embodiment, an electrolyte of a fluoride ion
electrochemical cell of the present invention comprises a solvent
and a fluoride salt, wherein the fluoride salt is at least
partially present in a dissolved state in the electrolyte so as to
generate fluoride ions in the electrolyte. Electrolytes in
electrochemical cells of the present invention include fluoride
salts having the formula: MF.sub.n, wherein M is a metal, and n is
an integer greater than 0. In some embodiments, for example, M is
an alkali metal, such as Na, K or Rb, or M is an alkaline earth
metal, such as Mg, Ca or Sr. In embodiments, M is a metal other
than lithium so as to provide enhanced safety and stability
relative to conventional state of the art lithium batteries and
lithium ion batteries. In some embodiments, the concentration of
the fluoride salt in the electrolyte is selected from the range of
about 0.1M to about 2.0M.
[0034] Electrolytes for anionic electrochemical cells of the
present invention, including fluoride ion electrochemical cells,
include aqueous electrolytes and nonaqueous electrolytes. Useful
electrolyte compositions for anionic electrochemical cells
preferably have one or more of the following properties. First,
electrolytes for some applications preferably have a high ionic
conductivity with respect to the anion charge carrier, for example
for fluoride ions. For example, some electrolytes useful in the
present invention comprise solvents, solvent mixtures and/or
additives providing conductivity for an anion charge carrier, such
as a fluoride ion anion charge carrier, greater than or equal to
0.0001 S cm.sup.-1, greater than or equal to 0.001 S cm.sup.-1, or
greater than or equal to 0.005 S cm.sup.-1. Second, electrolytes
for some embodiments are capable of dissolving an electrolyte salt,
such as a fluoride salt, so as to provide a source of anion charge
carriers at a useful concentration in the electrolyte. Third,
electrolytes of the present invention are preferably stable with
respect to decomposition at the electrodes. For example,
electrolytes of an embodiment of the present invention comprises
solvents, electrolyte salts, additives and anion charge carriers
that are stable at high electrode voltages, such as a difference
between positive and negative electrode voltages equal to or
greater than about 4.5V. Fourth, electrolytes of the present
invention preferable for some applications exhibit good safety
characteristics, such as flame retardance.
[0035] Optionally, electrolytes of the present electrochemical
cells include one or more additives. In an embodiment, the
electrolyte comprises an anion receptor, such as fluoride ion anion
receptors capable of coordinating fluoride ions of a fluoride salt,
and/or a cation receptor, for example a cation receptor capable of
coordinating metal ions of a fluoride salt. Useful anion receptors
in the present invention include, but are not limited to,
fluorinated boron-based anion receptors having electron withdrawing
ligands, such as fluorinated boranes, fluorinated boronates,
fluorinated borates, phenyl boron-based compounds and aza-ether
boron-based compounds. Useful cation receptors for electrolytes of
electrochemical cells of the present invention include, but are not
limited to, crown ethers, lariat ethers, metallacrown ethers,
calixcrowns (e.g., calyx(aza)crowns), tetrathiafulvalene crowns,
calixarenes, calix[4]arenediquinoes, tetrathiafulvalenes,
bis(calixcrown)tetrathiafulvalenes, and derivatives thereof. In
some embodiments, electrolytes of the present invention comprise
other inorganic, organic or gaseous additives. Additives in
electrolytes of the present invention are useful for: (i) enhancing
conductivity of the anion charge carrier, (ii) decreasing
flammability, (iii) enhancing electrode wetting, (iv) decreasing
electronic conductivity, and (v) enhancing the kinetics of anion
charge carriers at the electrodes, for example by enhancing
formation of a solid electrolyte interface (SEI) or by reducing the
buildup of discharge products. In an embodiment, the electrolyte
comprises a Lewis acid or a Lewis base such as, but not limited
to:
BF.sub.4.sup.-, PF.sub.6.sup.-, AsF.sub.6.sup.-, SbF.sub.6.sup.-,
BiF.sub.6.sup.-, AlF.sub.4.sup.-, GaF.sub.4.sup.-, InF.sub.4.sup.-,
TlF.sub.4.sup.-, SiF.sub.5.sup.-, GeF.sub.5.sup.-, SnF.sub.5.sup.-,
PbF.sub.5.sup.-, SF.sub.7.sup.-, IF.sub.6.sup.-, ClO.sub.4.sup.-,
CF.sub.3SO.sub.3.sup.-, (CF.sub.3SO.sub.2).sub.2N.sup.-,
C.sub.4F.sub.9SO.sub.3.sup.- and NR.sub.4.sup.+ (R.dbd.H or an
alkyl group C.sub.nH.sub.2n+1 n=integer).
[0036] Active materials for positive and negative electrodes of
fluoride ion electrochemical cells of the present invention include
fluoride ion host materials capable of accommodating fluoride ions
from the electrolyte during discharge and charging of the
electrochemical cell. In this context, accommodation of fluoride
ions includes insertion of fluoride ions into the host material,
intercalation of fluoride ions into the host material and/or
reaction of fluoride ions with the host material. Accommodation
includes alloy formation reactions, surface reaction and/or bulk
reactions with the host material. Use of fluoride ion host
materials that are capable of reversibly exchanging fluoride ions
with the electrolyte without significant degradation of the
fluoride ion host material upon cycling is preferred for secondary
fluoride ion batteries of the present invention.
[0037] In an embodiment, a negative electrode of a fluoride ion
electrochemical cell of the present invention comprises a fluoride
ion host material, such as a fluoride compound, having a low
standard reduction potential, preferably less than or equal to
about -1 V for some applications, and more preferably less than or
equal to about -2 V for some applications. Useful fluoride ion host
materials for negative electrodes of electrochemical cells of the
present invention include, but are not limited to: LaF.sub.x,
CaF.sub.x, AlF.sub.x, EuF.sub.x, LiC.sub.6, Li.sub.xSi, Li.sub.xGe,
Li.sub.x(CoTiSn), SnF.sub.x, InF.sub.x, VF.sub.x, CdF.sub.x,
CrF.sub.x, FeF.sub.x, ZnF.sub.x, GaF.sub.x, TiF.sub.x, NbF.sub.x,
MnF.sub.x, YbF.sub.x, ZrF.sub.x, SmF.sub.x, LaF.sub.x and
CeF.sub.x. Preferred fluoride host materials for negative
electrodes of electrochemical cell are element fluorides MF.sub.x,
where M is an alkali-earth metal (Mg, Ca, Ba), M is a transition
metal, M belongs to column 13 group (B, Al, Ga, In, TI), or M is a
rare-earth element (atomic number Z between 57 and 71). The present
invention also includes negative electrode fluoride ion host
materials comprising a polymer(s) capable of reversibly exchanging
fluoride ions comprising the anion ion charge carriers. Examples of
such a conjugated polymers are, but not limited to: polyacetylene,
polyaniline, polypyrrol, polythiophene and polyparaphenylene.
Polymer materials useful for negative electrodes in the present
invention are further set forth and described in Manecke, G. and
Strock, W., in "Encyclopedia of Polymer Science and Engineering,
2.sup.nd Edition, Kroschwitz, J., I., Editor. John Wiley, New York,
1986, vol. 5, pp. 725-755, which is hereby incorporated by
reference to the extent not inconsistent with the disclosure
herein.
[0038] In an embodiment, a positive electrode of a fluoride ion
electrochemical cell of the present invention comprises a fluoride
ion host material, such as a fluoride compound, having a high
standard reduction potential, preferably for some applications
greater than or equal to about 1 V, and more preferably for some
applications greater than or equal to about 2 V. In an embodiment,
the fluoride ion host material of the positive electrode is an
intercalation host material capable of accommodating fluoride ions
so as to generate a fluoride ion intercalation compound.
"Intercalation" refers to refers to the process wherein an ion
inserts into a host material to generate an intercalation compound
via a host/guest solid state redox reaction involving
electrochemical charge transfer processes coupled with insertion of
mobile guest ions, such as fluoride ions. Major structural features
of the host material are preserved after insertion of the guest
ions via intercalation. In some host materials, intercalation
refers to a process wherein guest ions are taken up with interlayer
gaps (e.g., galleries) of a layered host material.
[0039] Useful fluoride ion host materials for positive electrodes
of electrochemical cells of the present invention include, but are
not limited to, CFx, AgFx, CuFx, NiFx, CoFx, PbFx, CeFx, MnFx,
AuFx, PtFx, RhFx, VFx, OsFx, RuFx and FeFx. In an embodiment, the
fluoride ion host material of the positive electrode is a
subfluorinated carbonaceous material having a formula CFx, wherein
x is the average atomic ratio of fluorine atoms to carbon atoms and
is selected from the range of about 0.3 to about 1.0. Carbonaceous
materials useful for positive electrodes of this embodiment are
selected from the group consisting of graphite, coke, multiwalled
carbon nanotubes, multi-layered carbon nanofibers, multi-layered
carbon nanoparticles, carbon nanowhiskers and carbon nanorods. The
present invention also includes positive electrode fluoride ion
host materials comprising a polymer(s) capable of reversibly
exchanging fluoride ions comprising the anion ion charge carriers.
Examples of conjugated polymers for positive electrodes include,
but not limited to: polyacetylene, polyaniline, polypyrrol,
polythiophene and polyparaphenylene.
[0040] In an aspect, the present invention provides fluoride ion
electrochemical cells exhibiting enhanced device performance
relative to state of the art electrochemical cells such as lithium
ion batteries. Certain fluoride ion host material combinations for
positive and negative electrodes in fluoride ion electrochemical
cells are particularly beneficial for accessing useful device
performance. For example, use of a subfluorinated CF.sub.x positive
electrode, wherein x is selected over the range of about 0.3 to 1,
and a negative electrode comprising LiC.sub.6 or LaF.sub.x is
useful for accessing average operating cell voltages greater than
or equal to about 4 V, and in some embodiments greater than or
equal to about 4.5 V. Other useful positive electrode host
material/negative electrode host material combinations of the
present invention providing good device performance include
CuFx/LaFx, AgFx/LaFx, CoFx/LaFx, NiFx/LaFx, MnFx/LaFx, CuFx/AlFx,
AgFx/AlFx, NiFx/AlFx, NiFx/ZnFx, AgFx/ZnFx and MnFx/ZnFx (wherein
the convention is used corresponding to: [positive electrode host
material]/[negative electrode host material] to set for the
electrode combination).
[0041] In an embodiment, a fluoride ion electrochemical cell of the
present invention has an average operating cell voltage equal to or
greater than about 3.5 V, and preferably for some applications an
average operating cell voltage equal to or greater than about 4.5
V. In an embodiment, a fluoride ion electrochemical cell of the
present invention has a specific energy greater than or equal to
about 300 Wh kg.sup.-1, preferably greater than or equal to about
400 Wh kg.sup.-1. In an embodiment, the present invention provides
a fluoride ion secondary electrochemical cell having a cycle life
greater than or equal to about 500 cycles.
[0042] Useful solvents for electrolytes of the present invention
are capable of at least partially dissolving electrolyte salts,
such as fluoride salts, and include, but are not limited to one or
more solvent selected from the group consisting of propylene
carbonate, nitromethane, Toluene (tol); ethylmethyl carbonate
(EMC); Propylmethyl carbonate (PMC); Diethyl carbonate (DEC);
Dimethyl carbonate (DMC); Methyl butyrate (MB, 20.degree. C.);
n-Propyl acetate (PA); Ethyl acetate (EA); Methyl propionate (MP);
Methyl acetate (MA); 4-Methyl-1,3-dioxolane
(4MeDOL)(C.sub.4H.sub.8O.sub.2); 2-Methyltetrahydrofuran
(2MeTHF)(C.sub.5H.sub.10O); 1,2 Dimethoxyethane (DME); Methyl
formate (MF)(C.sub.2H.sub.4O.sub.2); Dichloromethane (DCM);
.gamma.-Butyrolactone (.gamma.-BL)(C.sub.4H.sub.6O.sub.2);
Propylene carbonate (PC)(C.sub.4H.sub.6O.sub.3); Ethylene carbonate
(EC, 40.degree. C.)(C.sub.3H.sub.4O.sub.3). Electrolytes, and
components thereof, comprising full or partially fluorinated
analogs of solvents, electrolyte salts and anion charge carriers
are beneficial for some applications because fluorination of these
materials imparts enhanced stability with respect to decomposition
at high electrode voltages and provides beneficial safety
characteristics, such as flame retardance. In the context of this
description, fluorine analogs include: (i) fully fluorinated
analogs wherein each hydrogen atom of the solvent, salt or anion
charge carrier molecule is replaced by a fluorine atom, and (ii)
partially fluorinated analogs wherein at least one hydrogen atom of
the solvent, salt or anion charge carrier molecule is replaced by a
fluorine atom. Preferred anion charge carrier in the electrolyte
include, but not limited to:
E.sup.-, BF.sub.4.sup.-, PF.sub.6.sup.-, AsF.sub.6.sup.-,
SbF.sub.6.sup.-, BiF.sub.6.sup.-, AlF.sub.4.sup.-, GaF.sub.4.sup.-,
InF.sub.4.sup.-, TlF.sub.4.sup.-, SiF.sub.5.sup.-, GeF.sub.5.sup.-,
SnF.sub.5.sup.-, PbF.sub.5.sup.-, SF.sub.7.sup.-, IF.sub.6.sup.-,
ClO.sub.4.sup.-, CF.sub.3SO.sub.3.sup.-,
(CF.sub.3SO.sub.2).sub.2N.sup.- and
C.sub.4F.sub.9SO.sub.3.sup.-.
[0043] The following references describe electrolyte compositions
useful in embodiments of the present invention, including fully
fluorinated and partially fluorinated solvents, salts and anion
charge carriers, and are hereby incorporated by reference in their
entireties to the extent not inconsistent with the present
disclosure: (1) Li[C.sub.2F.sub.5BF.sub.3] as an Electrolyte Salt
for 4 V Class Lithium-Ion Cells, Zhi-Bin Zhou, Masayuki takeda,
Takashi Fujii, Makoto Ue, Journal of Electrochemical Society,
152(2):A351-A356, 2005; (2) Fluorinated Superacidic Systems, George
A. Olah, Surya G. K. Prakash, Alain Goeppert, Actualite Chimique,
68-72 Suppl. 301-302, October-November 2006; (3) Electrochemical
properties of Li[C.sub.nF.sub.2n+1BF.sub.3] as Electrolyte Salts
for Lithium-ion Cells, Makoto Ue, Takashi Fujii, Zhi-Bin Zhou,
Masayuki Takeda, Shinichi Kinoshita, Solid State Ionics,
177:323-331, 2006; (4) Anodic Stability of Several Anions Examined
by AB Initio Molecular Orbital and Density Functional Theories,
Makoto Ue, Akinori Murakami, Shinichiro Nakamura, Journal of
Electrochemical Society, 149(12):A1572-A1577, 2002; (5) Intrinsic
Anion Oxidation Potentials, Patrik Johansson, Journal of Physical
Chemistry, 110.sub.--12077-12080, 2006; (6) Nonaqueous Liquid
Electrolytes for Lithium-based Rechargeable Batteries, Kang Xu,
Chem. Rev., 104:4303-4417, 2004; (7) The Electrochemical Oxidation
of Polyfluorophenyltrifluoroborate Anions in Acetonitrile, Leonid
A. Shundrin, Vadim V. Bardin, Hermann-Josef Frohn, Z. Anorg. Allg.
Chem. 630:1253-1257, 2004.
[0044] In another aspect, the present invention provides a method
for making an electrochemical cell comprising the steps of: (i)
providing a positive electrode; (ii) providing a negative
electrode; and (iii) providing an electrolyte between the positive
electrode and the negative electrode; the electrolyte capable of
conducting anion charge carriers; wherein the positive electrode
and negative electrode are capable of reversibly exchanging the
anion charge carriers with the electrolyte during charging or
discharging of the electrochemical cell.
[0045] In another aspect, the present invention provides a method
for generating an electrical current, the method comprising the
steps of: (i) providing an electrochemical cell; the
electrochemical comprising: a positive electrode; a negative
electrode; and an electrolyte provided between the positive
electrode and the negative electrode; the electrolyte capable of
conducting anion charge carriers; wherein the positive electrode
and negative electrode are capable of reversibly exchanging the
anion charge carriers with the electrolyte during charging or
discharging of the electrochemical cell; and (ii) discharging the
electrochemical cell. The method of this aspect of the present
invention may further comprise the step of charging the
electrochemical cell. In some embodiments of this aspect of the
present invention the anion charge carrier is fluoride ion
(F.sup.-).
[0046] In another aspect, the present invention provides a fluoride
ion secondary electrochemical cell comprising: (i) a positive
electrode comprising a first fluoride ion host material; said
positive electrode having a first standard electrode potential;
(ii) a negative electrode comprising a second fluoride ion host
material, said negative electrode having a second standard
electrode potential, wherein the difference between said first
standard electrode potential and said second standard electrode
potential is greater than or equal to about 3.5 V; and (iii) an
electrolyte provided between said positive electrode and said
negative electrode; said electrolyte capable of capable of
conducting fluoride ion charge carriers, said electrolyte
comprising a fluoride salt and a solvent; wherein at least a
portion of said fluoride salt is present in a dissolved state,
thereby generating said fluoride ion charge carriers in said
electrolyte; wherein said positive electrode and negative electrode
are capable of reversibly exchanging said fluoride ion charge
carriers with said electrolyte during charging or discharging of
said electrochemical cell. In some embodiments of this aspect of
the present invention the anion charge carrier is fluoride ion
(F.sup.-).
BRIEF DESCRIPTION OF THE DRAWINGS
[0047] FIG. 1. FIG. 1A provides a schematic diagram illustrating a
lithium ion battery during charging and FIG. 1B provides a
schematic diagram illustrating a lithium ion battery during
discharge.
[0048] FIG. 2. A schematic diagram showing the average working
potential of different negative electrode and positive electrode
materials and cell voltage for a conventional lithium ion
battery.
[0049] FIG. 3. FIG. 3A provides a schematic diagram illustrating a
fluoride ion battery (FIB) of the present invention during
discharge. FIG. 3B provides a schematic diagram showing the average
working potential for an example embodiment corresponding to a
LaF.sub.3-x negative electrode, a CF.sub.x positive electrode, and
an electrolyte comprising MF provided in an organic electrolyte,
wherein M is a metal such as K or Rb.
[0050] FIG. 4. FIG. 4 provides crystal structure of carbon
fluoride.
[0051] FIG. 5. FIG. 5 provides -ray diffraction patterns
(CuK.sub..alpha. radiation) from various positive electrode
materials evaluated. Diffraction patterns for carbon nanofiber,
KS15 and commercial CF.sub.1 are shown in FIG. 5.
[0052] FIG. 6. FIG. 6 provides discharge profiles for CF.sub.1
positive electrodes at room temperature for a variety of discharge
rates ranging from C/20 to C.
[0053] FIG. 7. FIG. 7 provides discharge profiles for CF.sub.0.530,
KS15 positive electrodes at room temperature for a variety of
discharge rates ranging from C/20 to C.
[0054] FIG. 8. FIG. 8 provides discharge profiles for CF.sub.0.647,
KS15 positive electrodes at room temperature for a variety of
discharge rates ranging from C/20 to 6 C.
[0055] FIG. 9. FIG. 9 provides discharge profiles for CF.sub.0.21,
carbon nanofiber positive electrodes at room temperature for a
variety of discharge rates ranging from C/20 to 6 C.
[0056] FIG. 10. FIG. 10 provides discharge profiles for
CF.sub.0.59, carbon nanofiber positive electrodes at room
temperature for a variety of discharge rates ranging from C/20 to 6
C.
[0057] FIG. 11. FIG. 11 provides discharge profiles for
CF.sub.0.76, carbon nanofiber positive electrodes at room
temperature for a variety of discharge rates ranging from C/20 to 6
C.
[0058] FIG. 12. FIG. 12 provides discharge profiles for
CF.sub.0.82, carbon nanofiber positive electrodes at room
temperature for a variety of discharge rates ranging from C/20 to 4
C.
[0059] FIG. 13. FIG. 13 provides charge-discharge profiles for
CF.sub.0.82, multiwalled nanotubes positive electrodes for a
voltage range 1.5V to 4.6V. Voltage is plotted on the Y axis (left
side), Current is plotted on the Y axis (right side) and time is
plotted on the X axis.
[0060] FIG. 14. FIG. 14 provides charge-discharge profiles for
CF.sub.0.82, multiwalled nanotubes positive electrodes for a
voltage range 1.5V to 4.8V. Voltage is plotted on the Y axis (left
side), Current is plotted on the Y axis (right side) and time is
plotted on the X axis.
[0061] FIG. 15. FIG. 15 provides charge-discharge profiles for
CF.sub.1 positive electrodes for a voltage range 1.5V to 4.8V.
Voltage is plotted on the Y axis (left side), Current is plotted on
the Y axis (right side) and time is plotted on the X axis.
[0062] FIG. 16. FIG. 16 provides plots of voltage (V) vs. time
(hours) for a Li/CF.sub.x half cell configuration for 4.6V and
4.8V. An increase in discharge capacity of 0.25% is observed at
4.8V.
[0063] FIG. 17. FIG. 17 provides plots of voltage (V) vs relative
capacity (%) for a Li/CF.sub.x half cell configuration with a
CF.sub.0.647 KS15 positive electrode for voltages ranging from 4.8V
and 5.4V. As shown in FIG. 17, the CF.sub.0.647 KS15 positive
electrode capacity increased with higher charge cutoff voltage over
the range of 4.8V to 5.4V.
[0064] FIG. 18. FIG. 18 provides cycle capacity curves of discharge
capacity (mAh/g-C) verse cycle number for various positive
electrode materials evaluated. This data demonstrates that 120
mAh/g-C rechargeable capacity has been achieved in a Li/CF.sub.x
half cell configuration charged to 4.8 V at a 2 C-rate.
[0065] FIG. 19. FIG. 19 provides plots of discharge cycle vs. cycle
number for CF.sub.0.82, multiwalled nanotubes positive electrodes
for voltages equal to 14.6V to 4.8V
[0066] FIG. 20. FIG. 20 provides a plot of the discharge rate
capability for a LiMn.sub.2O.sub.4 positive electrode.
[0067] FIG. 21. FIG. 21A provides a plot of discharge voltage vs
time indicating two time points (1) and (2) for which x-ray
diffraction patterns were taken. Thin graphite electrodes were used
(50 microns thick 3-4 mg). FIG. 21B shows x-ray diffraction
patterns acquired at two time points (1) and (2) shown in FIG. 21A.
FIG. 21C shows x-ray diffraction patterns acquired at two time
points (1) and (2) shown in FIG. 21A on an enlarge scale. The
diffraction patterns in FIGS. 21B and 21C show stage formation of
intercalated fluoride ions (a mixture of stage 2 and stage 3). Also
shown in The diffraction patterns in FIGS. 21B and 21C is that the
graphite phase completely disappeared at 5.2V and reappeared at
3.2V.
[0068] FIG. 22. Provides Electron Energy Loss Spectrum (EELS) of
the positive electrode material charged to 5.2V. Only pure fluorine
was detected in the sample, and no other species such as B or P are
present indicating other anions in the electrolyte were not
intercalated.
DETAILED DESCRIPTION OF THE INVENTION
[0069] Referring to the drawings, like numerals indicate like
elements and the same number appearing in more than one drawing
refers to the same element. In addition, hereinafter, the following
definitions apply:
[0070] "Standard electrode potential") (E.degree.) refers to the
electrode potential when concentrations of solutes are 1M, the gas
pressures are 1 atm and the temperature is 25 degrees Celsius. As
used herein standard electrode potentials are measured relative to
a standard hydrogen electrode.
[0071] "Anion charge carrier" refers to a negatively charge ion
provided in an electrolyte of an electrochemical cell that migrates
between positive and negative electrodes during discharge and
charging of the electrochemical cell. Anion charge carriers useful
in electrochemical cells of the present invention include, but are
not limited to, fluoride ions (F.sup.-), and the following other
anions:
BF.sub.4.sup.-, PF.sub.6.sup.-, AsF.sub.6.sup.-, SbF.sub.6.sup.-,
BiF.sub.6.sup.-, AlF.sub.4.sup.-, GaF.sub.4.sup.-, InF.sub.4.sup.-,
TlF.sub.4.sup.-, SiF.sub.5.sup.-, GeF.sub.5.sup.-, SnF.sub.5.sup.-,
PbF.sub.5.sup.-, SF.sub.7.sup.-, IF.sub.6.sup.-, ClO.sub.4.sup.-,
CF.sub.3SO.sub.3.sup.-, (CF.sub.3SO.sub.2).sub.2N.sup.- and
C.sub.4F.sub.9SO.sub.3.sup.-
[0072] "Fluoride ion host material" refers to a material capable of
accommodating fluoride ions. In this context, accommodating
includes insertion of fluoride ions into the host material,
intercalation of fluoride ions into the host material and/or
reaction of fluoride ions with the host material. Fluoride ion host
materials useful for positive or negative electrodes in
electrochemical cells of the present invention include, but are not
limited to, LaF.sub.x, CaF.sub.x, AlF.sub.x, EuF.sub.x, LiC.sub.6,
Li.sub.xSi, Li.sub.xGe, Li.sub.x(CoTiSn), SnF.sub.x, InF.sub.x,
VF.sub.x, CdF.sub.x, CrF.sub.x, FeF.sub.x, ZnF.sub.x, GaF.sub.x,
TiF.sub.x, NbF.sub.x, MnF.sub.x, YbF.sub.x, ZrF.sub.x, SmF.sub.x,
LaF.sub.x and CeF.sub.x, CFx, AgFx, CuFx, NiFx, CoFx, PbFx, CeFx,
MnFx, AuFx, PtFx, RhFx, VFx, OsFx, RuFx and FeFx. Preferred
fluoride host materials for negative electrodes of electrochemical
cell are element fluorides MF.sub.x, where M is an alkali-earth
metal (Mg, Ca, Ba), M is a transition metal, M belongs to column 13
group (B, Al, Ga, In, TI) or M is a rare-earth element (atomic
number Z between 57 and 71).
[0073] "Intercalation" refers to refers to the process wherein an
ion inserts into a host material to generate an intercalation
compound via a host/guest solid state redox reaction involving
electrochemical charge transfer processes coupled with insertion of
mobile guest ions, such as fluoride ions. Major structural features
of the host material are preserved after insertion of the guest
ions via intercalation. In some host materials, intercalation
refers to a process wherein guest ions are taken up with interlayer
gaps (e.g., galleries) of a layered host material. Examples of
intercalation compounds include fluoride ion intercalation
compounds wherein fluoride ions are inserted into a host material,
such as a layered fluoride host material or carbon host material.
Host materials useful for forming intercalation compounds for
electrodes of the present invention include, but are not limited
to, CF.sub.x, FeFx, MnFx, NiFx, CoFx, LiC6, LixSi, and LixGe.
[0074] The term "electrochemical cell" refers to devices and/or
device components that convert chemical energy into electrical
energy or electrical energy into chemical energy. Electrochemical
cells have two or more electrodes (e.g., positive and negative
electrodes) and an electrolyte, wherein electrode reactions
occurring at the electrode surfaces result in charge transfer
processes. Electrochemical cells include, but are not limited to,
primary batteries, secondary batteries and electrolysis systems.
General cell and/or battery construction is known in the art, see
e.g., U.S. Pat. Nos. 6,489,055, 4,052,539, 6,306,540, Seel and Dahn
J. Electrochem. Soc. 147(3) 892-898 (2000).
[0075] The term "capacity" is a characteristic of an
electrochemical cell that refers to the total amount of electrical
charge an electrochemical cell, such as a battery, is able to hold.
Capacity is typically expressed in units of ampere-hours. The term
"specific capacity" refers to the capacity output of an
electrochemical cell, such as a battery, per unit weight. Specific
capacity is typically expressed in units of ampere-hours
kg.sup.-1.
[0076] The term "discharge rate" refers to the current at which an
electrochemical cell is discharged. Discharge current can be
expressed in units of ampere-hours. Alternatively, discharge
current can be normalized to the rated capacity of the
electrochemical cell, and expressed as C/(X t), wherein C is the
capacity of the electrochemical cell, X is a variable and t is a
specified unit of time, as used herein, equal to 1 hour.
[0077] "Current density" refers to the current flowing per unit
electrode area.
[0078] In some embodiments, the positive electrode, negative
electrode or both are nanostructured materials. The term
"nanostructured" refers materials and/or structures have a
plurality of discrete structural domains with at least one physical
dimension (e.g., height, width, length, cross sectional dimension)
that is less than about 1 micron. In this context, structural
domains refer to features, components or portions of a material or
structure having a characteristic composition, morphology and/or
phase. Nanostructured materials useful as positive electrode active
materials include nanostructured composite particles having a
plurality of fluorinated carbon domains and unfluorinated carbon
domains. In some embodiments, nanostructured materials of the
present invention comprise a plurality of structural domains having
different compositions, morphologies and/or phase intermixed on a
very fine scale (e.g., at least smaller than 10's of nanometers).
Nanostructured materials useful as negative electrode active
materials include nanostructured composite particles having a
plurality of fluorinated metal domains and unfluorinated metal
domains. Preferred nanostrctured fluorinated metal host materials
for negative electrodes of electrochemical includes but not limited
to alkali-earth metals (Mg, Ca, Ba), transition metals, column 13
group elements (B, Al, Ga, In, TI) and rare-earth metals (atomic
number Z between 57 and 71). In some embodiments, nanostructured
materials for negative electrodes of the present invention comprise
a plurality of structural domains having different compositions,
morphologies and/or phase intermixed on a very fine scale (e.g., at
least smaller than 10's of nanometers).
[0079] "Active material" refers to the material in an electrode
that takes part in electrochemical reactions which store and/or
delivery energy in an electrochemical cell.
[0080] As used herein, the expression "subfluorinated carbonaceous
material" refers to a multiphase carbonaceous material having an
unfluorinated carbonaceous component. As used herein an
"unfluorinated carbonaceous component" includes unfluorinated
carbon compositions and/or phases, such as graphite, coke,
multiwalled carbon nanotubes, carbon nanofibers, carbon
nanowhiskers, multi-layered carbon nanoparticles, carbon
nanowhiskers, and carbon nanorods, and also includes slightly
fluorinated carbon compositions and/or phases. Slightly
fluorinated, in this context, refers to carbon that is weakly bound
to fluorine, as opposed to compositions wherein carbon is
covalently bonded to fluorine, as in CF.sub.1 and C.sub.2F phases.
Multiphase subfluorinated carbonaceous materials may comprises a
mixture of carbonaceous phases including, one or more unfluorinated
carbonaceous phases, and one or more fluorinated phase (e.g.,
poly(carbon monofluoride (CF.sub.1); poly(dicarbon monofluoride)
etc.). Subfluorinated carbonaceous materials include nanostructured
materials having fluorinated and unfluorinated domains.
Subfluorinated carbonaceous materials include carbonaceous
materials exposed to a fluorine source under conditions resulting
in incomplete or partial fluorination of a carbonaceous starting
material. Subfluorinated carbonaceous materials useful in the
present invention and related methods of making subfluorinated
carbonaceous materials are described in U.S. patent application
Ser. Nos. 11/253,360, 11/422,564 and 11/560,570 filed Oct. 18,
2005, Jun. 6, 2006, and Nov. 16, 2006, respectively, which are
hereby incorporated by reference in their entirety to the extent
not inconsistent with the present description. A range of
carbonaceous materials are useful for subfluorinated active
materials in positive electrodes of the present invention including
graphite, coke, and carbonaceous nanomaterials, such as multiwalled
carbon nanotubes, carbon nanofibers, multi-layered carbon
nanoparticles, carbon nanowhiskers and carbon nanorods.
[0081] As used herein, a carbon nanomaterial has at least one
dimension that is between one nanometer and one micron. In an
embodiment, at least one dimension of the nanomaterial is between 2
nm and 1000 nm. For carbon nanotubes, nanofibers, nanowhiskers or
nanorods the diameter of the tube, fiber, nanowhiskers or nanorod
falls within this size range. For carbon nanoparticles, the
diameter of the nanoparticle falls within this size range. Carbon
nanomaterials suitable for use with the invention include materials
which have total impurity levels less than 10% and carbon materials
doped with elements such as boron, nitrogen, silicon, tin and
phosphorous.
[0082] As used herein, the term "nanotube" refers to a tube-shaped
discrete fibril typically characterized by a diameter of typically
about 1 nm to about 20 nm. In addition, the nanotube typically
exhibits a length greater than about 10 times the diameter,
preferably greater than about 100 times the diameter. The term
"multi-wall" as used to describe nanotubes refers to nanotubes
having a layered structure, so that the nanotube comprises an outer
region of multiple continuous layers of ordered atoms and a
distinct inner core region or lumen. The layers are disposed
substantially concentrically about the longitudinal axis of the
fibril. For carbon nanotubes, the layers are graphene layers.
Carbon nanotubes have been synthesized in different forms as
Single-, Double- and Multi-Walled Carbon Nanotubes noted SWCNT,
DWCNT and MWCNT respectively. The diameter size ranges between
about 2 nm in SWCNTs and DWCNTs to about 20 nm in MWCNTs. In an
embodiment, the MWNT used in the invention have a diameter greater
than 5 nm, greater than 10 nm, between 10 and 20 nm, or about 20
nm.
[0083] Electrode refers to an electrical conductor where ions and
electrons are exchanged with electrolyte and an outer circuit.
"Positive electrode" and "cathode" are used synonymously in the
present description and refer to the electrode having the higher
electrode potential in an electrochemical cell (i.e. higher than
the negative electrode). "Negative electrode" and "anode" are used
synonymously in the present description and refer to the electrode
having the lower electrode potential in an electrochemical cell
(i.e. lower than the positive electrode). Cathodic reduction refers
to a gain of electron(s) of a chemical species, and anodic
oxidation refers to the loss of electron(s) of a chemical species.
Positive electrodes and negative electrodes of the present
electrochemical cell may further comprises a conductive diluent,
such as acetylene black, carbon black, powdered graphite, coke,
carbon fiber, and metallic powder, and/or may further comprises a
binder, such polymer binder. Useful binders for positive electrodes
in some embodiments comprise a fluoropolymer such as polyvinylidene
fluoride (PVDF). Positive and negative electrodes of the present
invention may be provided in a range of useful configurations and
form factors as known in the art of electrochemistry and battery
science, including thin electrode designs, such as thin film
electrode configurations. Electrodes are manufactured as disclosed
herein and as known in the art, including as disclosed in, for
example, U.S. Pat. Nos. 4,052,539, 6,306,540, 6,852,446. For some
embodiments, the electrode is typically fabricated by depositing a
slurry of the electrode material, an electrically conductive inert
material, the binder, and a liquid carrier on the electrode current
collector, and then evaporating the carrier to leave a coherent
mass in electrical contact with the current collector.
[0084] "Electrode potential" refers to a voltage, usually measured
against a reference electrode, due to the presence within or in
contact with the electrode of chemical species at different
oxidation (valence) states.
[0085] "Electrolyte" refers to an ionic conductor which can be in
the solid state, the liquid state (most common) or more rarely a
gas (e.g., plasma).
[0086] "Cation" refers to a positively charged ion, and "anion"
refers to a negatively charged ion.
[0087] The present invention provides primary and secondary anionic
electrochemical cells utilizing fluoride ion charge carriers and
active electrode materials comprising fluoride ion host materials
that provides an alternative to conventional state of the art
lithium batteries and lithium ion batteries. Advantages of the
present electrochemical cells over lithium based systems include
accessing higher specific capacities, larger average operating
voltages and improving safety.
[0088] Anionic electrochemical cells of the present invention,
including fluoride ion electrochemical cells, operate on the
principle of simultaneous oxidation and reduction reactions that
involve accommodation and release of anion charge carriers by
positive and negative electrodes comprising different anion charge
carrier host materials. In these systems, anion charge carriers
shuttle back and forth between positive and negative electrodes
during discharge and charging of the anionic electrochemical cell.
The following electrode half reactions, cells reactions and
electrolyte reactions are provided to set forth and describe the
fundamental principles by which anionic electrochemical cells of
the present invention operate.
1. Electrode Reactions
[0089] A.sup.- is the anion charge carrier, PA.sub.n is the
positive electrode anion host material and NA.sub.m is the negative
electrode anion host material. In a primary battery, only discharge
reactions occur: [0090] At the positive electrode, A.sup.- is
released:
[0090] ##STR00001## [0091] At the negative electrode, A.sup.- is
occluded
##STR00002##
[0091] Accordingly, the cell overall reaction is:
##STR00003##
In a rechargeable battery, equations (1) and (2) are reversed
during charge, therefore the overall cell reaction is:
##STR00004##
2. Electrolyte Formation Reactions:
[0092] The present invention includes several sources of dissolved
A.sup.- anion in an electrolyte provide between positive and
negative electrodes: [0093] (i) A soluble compound such as a salt
C.sub.qA.sub.p; where C is a monovalent, divalent, a trivalent,
multivalent cation (C.sup.n+, 1.ltoreq.n.ltoreq.6). For example, if
C is monovalent cation the salt dissolution equilibrium is written
as:
[0093] C.sub.qA.sub.pqC.sup.++pA.sup.- (here p=q) (5) [0094] Here
the use of a cation receptor R and/or an anion receptor R' may
enhance the solubility:
[0094] C.sub.qA.sub.p+zqRqCR.sub.z.sup.++pA.sup.- (6)
C.sub.qA.sub.p+z'pR'qC.sup.++pAR'.sub.z'.sup.- (7) [0095] (ii) A
soluble anion XA.sub.p.sup.- that releases A.sup.-;
[0095] XA.sub.p.sup.-XA.sub.p-1+A.sup.- (8)
Optionally a cation receptor R and/or an anion receptor R' may be
provide in the electrolyte to enhance the solubility of
A.sup.-.
[0096] As an example of these concepts, provided below are the half
reactions, cell reaction and electrolyte reactions for discharge of
a fluoride ion electrochemical cell of the present invention
comprising a LiC.sub.6 negative electrode, a CFx positive electrode
and a F- conductive electrolyte.
Discharge Reactions:
[0097] negative electrode:
LiC.sub.6+F.sup.-.fwdarw.6C+LiF+e.sup.- [0098] (negative electrode
accommodates F during discharge) positive electrode:
[0098] CFx+x.fwdarw.xe.sup.-.fwdarw.C+xF- [0099] (positive
electrode releases F during discharge) cell reaction:
[0099] xLiC.sub.6+CFx.fwdarw.(1+6x)C+xLiF [0100] (F.sup.- is
transferred between positive electrode and negative electrode
during discharge) Electrolyte: Optionally, two types of reactions
can enhance the F- dissolution:
[0100] LiF+yLA.fwdarw.Li.sup.++(LA).sub.yF.sup.-, or
LiF+zLB.fwdarw.Li(LB).sub.z.sup.++F.sup.-
(LA=Lewis acid such as PF.sub.5, BF.sub.3 or an anion receptor,
LB=Lewis base such as PF.sub.6.sup.-, BF.sub.4.sup.- or a cation
receptor: i. e. crown ether).
[0101] To further describe and set forth the anionic
electrochemical cells of the present invention, the discussion
below draws a comparison of the present systems with conventional
lithium ion battery technology. A typical lithium ion battery (LIB)
comprises three fundamental elements: (1) a carbon-based negative
electrode (anode), (2) lithium cation (Li+) conducting electrolyte,
and (3) a transition metal oxide positive electrode (cathode)
(e.g., LiCoO.sub.2). Lithium cation (Li+) is the charge carrier in
these systems, and these electrochemical cells function via
simultaneous insertion and de-insertion reactions occurring at
positive and negative electrodes in concert with electron transport
between electrodes. During charge and discharge of a lithium ion
battery, Li+ ions are shuttled between the negative and positive
electrode. The reversible dual intercalation mechanism of these
batteries gives rise to the term "rocking chair" or "shuttle-cock"
batteries.
[0102] FIG. 1A provides a schematic diagram illustrating a lithium
ion battery during charging. During charging lithium ions are
released from the positive electrode (i.e., designated as cathode
in FIG. 1A), migrate through the electrolyte and are accommodated
by the negative electrode (i.e., designated as anode in FIG. 1A).
As shown in FIG. 1A, the direction of the flow of electrons during
charging is from the positive electrode to the negative electrode.
FIG. 1B provides a schematic diagram illustrating a lithium ion
battery during discharge. During discharge, lithium ions are
released from the negative electrode (i.e., designated as anode in
FIG. 1B), migrate through the electrolyte and are accommodated by
the positive electrode (i.e., designated as cathode in FIG. 1B). As
shown in FIG. 1B, the direction of the flow of electrons during
charging is from the negative electrode to the positive
electrode.
[0103] FIG. 2 provides schematic diagram showing the average
working potential of different negative electrode and positive
electrode materials and cell voltage for a conventional lithium ion
battery. The average operating voltage of the electrochemical cell
arises, in part, from the difference between the chemical potential
of Li.sup.+ ion in the negative and positive electrodes. In the
example shown in FIG. 2, the difference in the electrode potentials
of Li.sub.xC.sub.6 and Li.sub.xCoO.sub.2 is approximately 4V. The
LIB cell extended reaction for this example is:
2LiCoO.sub.2+6C2Li.sub.0.5CoO.sub.2+LiC.sub.6
The theoretical energy density of this example LIB system can be
calculated as follows:
E ( LIB ) = F ( OCV ) 3.6 [ ( 2 M ( LiCoO 2 ) + 6 M ( C ) ] = 96500
.times. 4.2 3.6 .times. ( 196 + 72 ) = 420 Wh / kg ##EQU00001##
[0104] In electrochemical cells of the present invention the charge
carrier is a negatively charged anion. In fluoride ion
electrochemical cells, for example, the anion charge carrier is
fluoride ion (F.sup.-1). Similar to lithium ion batteries, fluoride
ion electrochemical cells of the present invention operate on the
principle of simultaneous fluoride ion insertion and de-insertion
reactions occurring at positive and negative electrodes in concert
with electron transport between electrodes. During charge and
discharge of a fluoride ion electrochemical cell, F.sup.- ions are
shuttled between the negative and positive electrodes.
[0105] FIG. 3A provides a schematic diagram illustrating a fluoride
ion electrochemical cell during discharge. During discharge
fluoride anions are released from the positive electrode (i.e.,
designated as cathode in FIG. 3A), migrate through the electrolyte
and are accommodated by the negative electrode (i.e., designated as
anode in FIG. 3A). As shown in FIG. 3A, the direction of the flow
of electrons during discharge is from the negative electrode to the
positive electrode. During charging of a fluoride ion
electrochemical cell, fluoride anions are released from the
negative electrode migrate through the electrolyte and are
accommodated by the positive electrode. The direction of the flow
of electrons during charging is from the positive electrode to the
negative electrode. Release and accommodation of fluoride ions
during discharge and charging results from oxidation and reduction
reactions occurring at the electrodes.
[0106] Similar to the description above relating to lithium ion
batteries, the open-circuit voltage in a fluoride ion
electrochemical cell results, at least in part, from differences in
the chemical potential of the fluoride ions in the negative
electrode and the positive electrode. The positive electrode and
negative electrode are respectively a high voltage and a low
voltage fluorides, able to reversible exchange F.sub.- with
electrolyte, for example: [0107] Positive electrode: CF.sub.x,
AgF.sub.2-x, CuF.sub.3-x, NiF.sub.3-x, . . . [0108] Negative
electrode: LaF.sub.3-x, CaF.sub.2-x, AlF.sub.3-x, EuF.sub.3-x, . .
.
[0109] FIG. 3B provides a schematic diagram showing the average
working potential for an example embodiment corresponding to a
LaF.sub.3-x negative electrode, a CF.sub.x positive electrode, and
an electrolyte comprising MF provided in an organic electrolyte,
wherein M is a metal such as K or Rb. The relevant parameters, half
reactions and cell reaction are summarized below for this example:
[0110] Negative electrode: LaF.sub.3 [0111] Positive electrode:
CF.sub.y [0112] Electrolyte: MF in organic electrolyte (M=K, Rb, .
. . ) [0113] Electrode reactions:
[0113] Negative electrode:
LaF.sub.3+3xe.sup.-LaF.sub.3(1-x)+3xF.sup.- (x.ltoreq.1) (9)
Positive electrode: 3CF.sub.y+3xF.sup.-3CF.sub.x+y+3xe.sup.-
(y.ltoreq.1-x) (10) [0114] Cell reaction:
[0114] LaF.sub.3+3CF.sub.yLaF.sub.3(1-x)+3CF.sub.x+y (11)
[0115] As shown in FIG. 3B, the difference in the electrode
potentials for this example is about 4.5 V. The theoretical cell
voltage takes into account the La.sup.3+/La and the
CF.sub.x/F.sup.- redox couples and the open circuit voltage OCV at
the end of charge is expected to be approximately 4.5V, which is
larger than that of a conventional lithium ion battery (see
calculation above). The theoretical energy density for this example
fluoride ion battery (FIB) system can be calculated as follows:
The FIB Energy Density:
[0116] With cell reaction (3) and x=1, y=0;
(LaF.sub.3+3CF.sub.yLaF.sub.3(1-x)+3CF.sub.x+y), The theoretical
energy density is:
E ( FIB ) = 3 F ( OCV ) 3.6 [ ( M ( LaF 3 ) + 3 M ( C ) ] = 3
.times. 96500 .times. 4.5 3.6 .times. ( 196 + 36 ) = 1560 Wh / kg
##EQU00002##
This calculation give rise of a ratio of the theoretical energy
density for the example fluoride ion electrochemical cell and the
example lithium ion battery described above equal to 3.7:
E ( FIB ) E ( LIB ) = 1560 420 = 3.7 x ##EQU00003##
[0117] Table 1 provides a comparison of the performance attributes
and compositions of lithium ion batteries and the fluoride ion
electrochemical cells described above. Benefits of the present
fluoride ion batteries (FIBs) include: (i) enhanced safety of the
fluoride ion electrochemical cell, (ii) higher operating voltage of
the fluoride ion electrochemical cell; (iii) larger energy density
in the fluoride ion electrochemical cell; and (iv) lower costs of
the fluoride ion electrochemical cell.
TABLE-US-00001 TABLE 1 Comparison of the performance attributes and
compositions of lithium ion batteries and the fluoride ion
electrochemical cells LIB FIB Comments Positive LiCoO2, CF.sub.x,
AgF.sub.x, CuF.sub.x, Solid fluorides are electrode
Li(NiCoMn)O.sub.2, NiF.sub.x more stable than LiFePO.sub.4 oxides
Negative LiC.sub.6, LixSi, LaF.sub.x, EuF.sub.x, LiC.sub.6 High
capacity electrode LixSn, negative electrodes Lix(CoSnTi) in FIBS
Electrolyte LiPF.sub.6 in MF in PC or Cheap and more EC-DME-DMC
nitromethane stable electrolyte in (M.dbd.Li, K, Rb) FIB Voltage
(V) 3-5 V 3.5-5.5 V Higher operating voltage. High stability at
high voltages Energy 340 Wh/kh 1560 (Theor.) of 3.7.times. energy
density (Theor.) the LaF.sub.3/CF.sub.x in FIBs couple Safety
Lithium is Fluorides are very Increased safety due unstable stable.
No soluble to more robust metal used chemistry Cost High when Co
Except for Ag, FIB should be 4-5.times. is used most positive
cheaper in $/Wh electrodes and negative electrodes are cheap
[0118] Fluoride Ion batteries (FIBs) are pure anion-type batteries
where the anode and the cathode reactions involve fluoride anion
F.sup.- accommodation and release. FIBs can be primary batteries
and rechargeable batteries depending on the reversibility of the
electrode reactions. However, both primary and rechargeable FIBs
require a F.sup.- anion conductive electrolyte. Fluoride ion
batteries can be further categorized into two classes.
[0119] In the first class, both positive and negative electrodes
contain fluoride anions. A fluoride ion electrochemical cell having
a LaF.sub.3 anode and a CF.sub.x cathode is an example of this
first class. The electrode half reactions and cell reactions for
the (LaF.sub.3/CF.sub.x) system are:
LaF.sub.3 anode:
LaF.sub.3+3ye.sup.-.fwdarw.LaF.sub.3(1-y)+3yF.sup.- (charge)
CF.sub.x cathode:
CF.sub.x+xe.sup.-.fwdarw.C+xF.sup.- (discharge)
Cell reaction:
xLaF.sub.3+3yC.fwdarw.xLaF.sub.3(1-y)+3yCF.sub.x (charge)
xLaF.sub.3(1-y)+3yCF.sub.x.fwdarw.xLaF.sub.3+3yC
Other examples of this first class of the fluoride ion
electrochemical cell include, but are not limited to,
(anode/cathode) couples: (LaF.sub.3/AgF.sub.x),
(LaF.sub.3/NiF.sub.x), (EuF.sub.3/CF.sub.x),
(EuF.sub.3/CuF.sub.x)
[0120] In the second class, only one electrode contains fluoride
anions. A fluoride ion electrochemical cell having a LiC.sub.6
anode and a CF.sub.x cathode is an example of this second class.
The electrode half reactions and cell reactions for the
(LiC.sub.6/CF.sub.x) system are:
LiC.sub.6 anode:
LiC.sub.6+F.sup.-.fwdarw.6C+LiF+e.sup.- (discharge)
CF.sub.x cathode:
CF.sub.x+xe.sup.-.fwdarw.C+xF.sup.- (discharge)
Cell reaction:
xLiC.sub.6+CF.sub.x.fwdarw.(6x+1)C+xLiF (discharge)
(6x+1)C+xLiF.fwdarw.xLiC.sub.6+CF.sub.x (charge)
Other examples of this first class of the fluoride ion
electrochemical cell include, but are not limited to,
(anode/cathode) couples: (LiC.sub.6/AgF.sub.x),
(LiC.sub.6/NiF.sub.x), (Li.sub.xSi/CF.sub.x), and
(Li.sub.xSi/CuF.sub.x).
[0121] Aspects of the present invention are further set forth and
described in the following Examples.
Example 1
Fluoride Ion Secondary Electrochemical Cell with Li/CFx Half Cell
Configurations
[0122] 1.a. Introduction.
[0123] To demonstrate the benefits of the present fluoride ion
electrochemical cells, cells comprising a CF.sub.x positive
electrode and metallic lithium negative electrode were constructed
and evaluated with respect to electrochemical performance. The
results shown here demonstrate that fluoride ion electrochemical
cells exhibit useful rechargeable capacities under reasonable
charge-discharge rates at room temperatures.
1.b. Experimental.
[0124] Two types of carbon fluorides CF.sub.x were synthesized and
used as positive electrodes in lithium cells in this example; 1)
stoichiometric (commercial) CF.sub.1 based on coke and, 2)
sub-fluorinated CF.sub.x (x<1) based on graphite and
multi-walled carbon nanotubes (MWNTs). Carbon fluoride is obtained
from high temperature fluorination of coke graphite or MWNT carbon
powders, following reaction:
C(s)+x/2F.sub.2(g).fwdarw.CF(s) (s=solid and g=gas)
Several kinds of fully fluorinated and subfluorinated carbon,
referred to as CF.sub.x, were investigated in the present example
for use as the active material for the positive electrode: [0125]
(1) Commercial CFx (wherein x=1.0); This subfluorinated
carbonanceous material was obtained from Lodestar, NY, USA, and
corresponds to their PC10 product which is a fully fluorinated coke
material. This subfluorinated carbonanceous material is
synonymously referred to as "commercial", "commercial CFx", and
"CFx (x=1)" in the Figures and throughout this example; [0126] (2)
Subfluorinated carbon synthesized by fluorination of synthetic
graphite (CFx wherein x=0.530, 0.647). This subfluorinated material
was synthesized via partial fluorination of synthetic graphite
produced by Timcal, Switzerland. These subfluorinated graphite
materials are referred to as "KS15" in the figures and throughout
this example. The compositions of these materials are further
characterized by reference to the atomic ratio of fluorine to
carbon (i.e., the variable x in the formula CFx); and [0127] (3)
Subfluorinated carbons synthesized by fluorination of multiwalled
carbon nanotubes (MWNTs), (CFx wherein x=0.21, 0.59, 0.76, 0.82).
This subfluorinated material was synthesized via partial
fluorination of MWNTS obtained from MER, Tucson, Ariz., USA. This
subfluorinated material is synonymously referred to as "carbon
nanofiber", "MWNT" and "multiwalled carbon nanotubes" in the
figures and throughout this example. The compositions of these
subfluorinated carbonaceous materials are further characterized by
reference to the atomic ratio of fluorine to carbon (i.e., the
variable x in the formula CFx)
[0128] The positive electrode consisted of a selected CF.sub.x
material with the addition of Acetylene Black Graphite (ABG) and
PVDF as a binder, with respective percentages of 75 wt %, 10 wt %
and 15 wt %. These three materials were mixed together in Acetone
solution with dibutyl phthalate DBP (20 wt %). The solution was
then evaporated and finally, a thin film of CF.sub.x positive
electrode was obtained (100-120 .mu.m thick). The film was cut to
diameter (15.2 mm) and washed in Methanol and dried at 80.degree.
C. overnight in vacuum. The electrode weight is 10.about.20 mg.
Structure of coin type Li/CF.sub.x test batteries;
Li/PC-DME-LiBF.sub.4/CF.sub.x, 2016 coin cells. (Separator; Sanyo
Celgard, diameter (19 mm), thickness (25 .mu.m), strong, low
electrical resistivity and high porosity (55%).)
1.c. Experimental Results
[0129] FIG. 4 provides crystal structure of carbon fluoride. FIG. 5
provides -ray diffraction patterns (CuK.sub..alpha. radiation) from
various positive electrode materials evaluated comprising
commercial CF.sub.1 and various subfluorinated carbonaceous
materials. Diffraction patterns for a variety of subfluorinated
carbon nanofiber samples (i.e., MWNTs, CFx; x=0.210, 0.590, 0.760
and 0.820), a variety of subfluorinated KS15 graphite samples
(i.e., CFx; x=0.53 and 0.647); and commercial CF.sub.1 sample
(i.e.; CFx, x=1) are shown in FIG. 5.
[0130] The various fluorinated carbon active materials were also
characterized via electrochemical methods. In these experiments,
Cyclic Chronopotentiometry (constant current) is used to follow the
discharge and charge of cells. The applied current calculated from
the theoretical capacity. Thus, for different fixed C/n rate
(C/10.about.1 C), one can determine the current I:
I = C n = m CF x .times. Q th ( x ) n ##EQU00004## Q th ( x ) =
96500 x 3.6 ( 12 + 19 x ) ( m AH / g ) ##EQU00004.2##
m.sub.CFx=mass of active material (g), Q.sub.th=theoretical
capacity in mAh/g Note: Q.sub.th is expressed in mAh/g of CF.sub.x
during the first discharge and in mAh/g of C during cycling
[0131] In these measurements, the first discharge and subsequent
cycling reactions were as follows: [0132] First discharge:
[0132] CF.sub.x+Li.sup.++xe.sup.-.fwdarw.C+xLiF (3.2V-1.5V vs. Li)
[0133] Cycling reaction:
[0133] C+yA.sup.-CA.sub.y+ye.sup.- (1.5V-up to 4.8V vs. Li)
(A.sup.-=anion=F.sup.-)
[0134] FIGS. 6-12 provides first discharge curves for a number of
positive electrode carbonaceous active materials. FIG. 6 provides
discharge profiles for commercial CF.sub.1 positive electrodes at
room temperature for a variety of discharge rates ranging from C/20
to C. FIG. 7 provides discharge profiles for CF.sub.0.530, KS15
positive electrodes at room temperature for a variety of discharge
rates ranging from C/20 to C. FIG. 8 provides discharge profiles
for CF.sub.0.647, KS15 positive electrodes at room temperature for
a variety of discharge rates ranging from C/20 to 6 C. FIG. 9
provides discharge profiles for CF.sub.0.21, carbon nanofiber
positive electrodes at room temperature for a variety of discharge
rates ranging from C/20 to 6 C. FIG. 10 provides discharge profiles
for CF.sub.0.59, carbon nanofiber positive electrodes at room
temperature for a variety of discharge rates ranging from C/20 to 6
C. FIG. 11 provides discharge profiles for CF.sub.0.76, carbon
nanofiber positive electrodes at room temperature for a variety of
discharge rates ranging from C/20 to 6 C. FIG. 12 provides
discharge profiles for CF.sub.0.82, carbon nanofiber positive
electrodes at room temperature for a variety of discharge rates
ranging from C/20 to 4 C. The observed discharge profiles are
consistent with a first discharge cell reaction of:
CF.sub.x+Li.sup.++xe.sup.-.fwdarw.C+xLiF (3.2V-1.5V vs. Li).
[0135] FIGS. 13-15 provide plots showing cycling tests for several
positive electrode carbonaceous active materials. FIG. 13 provides
charge-discharge profiles for CF.sub.0.82, multiwalled nanotubes
positive electrodes for a voltage range 1.5V to 4.6V. Voltage is
plotted on the Y axis (left side), Current is plotted on the Y axis
(right side) and time is plotted on the X axis. FIG. 14 provides
charge-discharge profiles for CF.sub.0.82, multiwalled nanotubes
positive electrodes for a voltage range 1.5V to 4.8V. Voltage is
plotted on the Y axis (left side), Current is plotted on the Y axis
(right side) and time is plotted on the X axis. FIG. 15 provides
charge-discharge profiles for CF.sub.1 positive electrodes for a
voltage range 1.5V to 4.8V. Voltage is plotted on the Y axis (left
side), Current is plotted on the Y axis (right side) and time is
plotted on the X axis. These figures show that the positive
electrode materials examined, particularly CF.sub.x; x=0.82, MWNT
(see, FIGS. 13 and 14), have the ability to cycle and exhibit a
stable cycle capacity. FIG. 16 provides plots of voltage (V) vs.
time (hours) for a Li/CF.sub.x half cell configuration having a
CF.sub.x; x=0.82, MWNT positive electrode for 4.6V and 4.8V. An
increase in discharge capacity of 0.25% is observed corresponding
to an increase in charging voltage from 4.6V to 4.8V. FIG. 17
provides plots of voltage (V) vs relative capacity (%) for a
Li/CF.sub.x half cell configuration having a CF.sub.0.647 KS15
positive electrode for voltages ranging from 4.8V and 5.4V. As
shown in FIG. 17, the CF.sub.0.647 KS15 positive electrode capacity
increased with higher charge cutoff voltage over the range of 4.8V
to 5.4V. FIGS. 16 and 17 show a measurable increase in discharge
capacity resulting from an increase in charge voltage for the CFx
materials examined. The observed charge-discharge profiles shown in
FIGS. 13-17 are consistent with a cycling cell reaction of:
C+yA.sup.-CA.sub.y+ye.sup.- (1.5V-up to 4.8V vs. Li)
(A.sup.-=anion=F.sup.-), and demonstrate that Li.sup.+ is not
participating in the cycling reactions.
[0136] FIG. 18 provides cycle capacity curves of discharge capacity
(mAh/g-C) verse cycle number for various positive electrode
materials evaluated include commercial CF.sub.1, subfluorinated
KS15 graphite (CFx, x=0.53 & 0.647) and subfluorinated MWNTs
(CFx; x=0.21, 0.59, 0.76 and 0.82). The charging voltage for these
measurements was 4.6 V, with the exception of the top most plot
(dotted and dashed line) which corresponds to a charge voltage of
4.8V and a positive electrode having an active material comprising
subfluorinated MWNTs with CFx, X=0.82. Similar to the
charge-discharge profiles shown in FIGS. 16 and 17, a significant
increase in discharge capacity is observed for subfluorinated MWNTs
with CFx, X=0.82 upon increasing the charging voltage from 4.6 V to
4.8V.
[0137] As shown in FIG. 18, the cell configuration having a
commercial CF.sub.1 active positive electrode material does not
exhibit very good cycling, most likely due to significant
degradation in the structural integrity of CF.sub.1 occurring
during the first discharge. It is likely that the porosity of this
positive electrode active material contributed to its degradation,
which may have been caused by exfoliation initiated by the reaction
between fluoride ions and lithium ions. In contrast, the
subfluorinated carbonaceous materials studied (e.g., graphite,
MWNTs) exhibit very good cycling performance. This is likely due to
the lower amount of fluorine and decreased porosity of these
materials as compared to commercial CFx, x=1. It is important to
note that the subfluorinated MWNTs provides the best cycling
performance likely due to its greater mechanical integrity as
compared to graphite and commercial CF.sub.1.
[0138] The data in FIG. 18 demonstrates that 120 mAh/g-C
rechargeable capacity has been achieved in a Li/CF.sub.x half cell
configuration with a positive electrode having an active material
comprising subfluorinated MWNTs with CFx, X=0.82 and charged to 4.8
V at a 2 C-rate. For the purpose of comparison, FIG. 20 provides a
plot of the discharge rate capability for a LiMn.sub.2O.sub.4
positive electrode. These measurements show that sub-fluorinated
CF.sub.x materials made of Multi-walled Carbon Nanotubes outperform
commercially available LiMn.sub.2O.sub.4 as positive electrodes in
lithium rechargeable batteries.
[0139] FIG. 19 provides plots of discharge cycle vs. cycle number
for CF.sub.0.82 multiwalled nanotubes positive electrodes for
voltages equal to 4.6V to 4.8V. In these plots, discharge capacity
(y-axis; mAh/g-C) is plots vs. cycle number in arbitrary units.
FIG. 19 shows that stable discharge characteristics are observed
for this positive electrode active material for at least
approximately 50 cycles.
[0140] To verify that fluoride ion was participating in the
oxidation and reduction reactions at the electrode, X-ray
diffraction patterns of the positive electrode were acquired under
different experimental conditions. FIG. 21A provides a plot of
discharge voltage vs time indicating two time points (1) and (2)
for which x-ray diffraction patterns were taken. X-ray diffraction
patterns were also acquired for the unused positive electrode. Thin
graphite electrodes were used (50 microns thick 3-4 mg). FIG. 21B
shows x-ray diffraction patterns acquired at two time points (1)
and (2) shown in FIG. 21A. FIG. 21C shows x-ray diffraction
patterns acquired at two time points (1) and (2) shown in FIG. 21A
on an enlarge scale.
[0141] The diffraction patterns in FIGS. 21B and 21C corresponding
to charging to 5.2 V and subsequent discharge to 3.2 V show stage
formation of intercalated fluoride ions (a mixture of stage 2 and
stage 3). Particularly, the appearance of the (002)--2, (003)--3
and (004)--3 peaks indicate that intercalated fluoride anions are
present upon charging and discharge. As shown by a comparison
between the diffraction patterns corresponding to the unused
positive electrode, the positive electrode at 5.2V and the positive
electrode at 3.2V, the graphite phase completely disappears upon
charging to 5.2V and subsequently reappears upon discharge to 3.2V.
The C(002) graphite peak is present in the diffraction pattern
corresponding to 3.2V shows that graphite is present upon
de-intercalation of the fluoride ions. Further, the sharp peak
width of the C(002) graphite peak in the 3.2 V diffraction pattern
indicates that graphite maintains its structural integrity upon
charging and discharge. This result demonstrates that the fluoride
ion intercalation and de-intercalation process is reversible and
does not result in a phase change from crystalline graphite to an
amorphous carbon phase. These result are consistent with a cycling
cell reaction of:
C+yA.sup.-CA.sub.y+ye.sup.- (1.5V-up to 4.8V vs. Li)
(A.sup.-=anion=F.sup.-),
and provide further evidence that that Li.sup.+ is not
participating in the cycling reactions.
[0142] To further characterize the composition of the
subfluorinated graphite active material for the positive electrode
Electron Energy Loss Spectra (EELS) were acquired for conditions
corresponding to charging the electrochemical cell to 5.2 V. EELS
is a useful for technique for characterizing the elemental
composition of materials as it is very sensitive to the presence of
elements in a sample and can identify elements in a material very
accurately. FIG. 22 provides an EELS spectrum of the positive
electrode active material charged to 5.2V. Only two peaks are shown
in FIG. 22, and both of these peaks can be assigned to the presence
of fluorine in the positive electrode active material. Peaks
corresponding to other non-carbon elements, such as B or P, are not
present. This observation provides evidence that other anions in
the electrolyte, such as PF.sub.6.sup.- or BF.sub.4.sup.-, were not
intercalated.
1.d. Conclusions
[0143] Sub-fluorinated carbons materials, CF.sub.x, are excellent
example of a positive electrode materials for fluorine anion
rechargeable batteries. They show stable cycle life, high capacity,
high discharge voltage and high rate capability. X-ray
diffractometry coupled with electron energy loss spectrometry show
that charge carrier fluoride anions do reversibly intercalate into
the carbon matrix, whether the later consists of graphite, coke or
multiwalled carbon nanotube. Staging occurs, which draws similarity
of fluorine anion intercalation with lithium cation intercalation
in Li.sub.xC.sub.6 negative electrodes. Fluorine anion storage
capacity increases with charge cutoff voltage by about 150% between
4.5V and 5.5V.
Example 2
Anion and Cation Receptors for Fluoride Ion Electrochemical
Cells
[0144] This example provides summary of anion and cation receptors
useful in the present invention. A number of fluoride ion receptors
are specifically exemplified that are capable of enhancing
solubility of fluoride salts and capable of enhancing the ionic
conductive of electroyles in electrochemical cells of the present
invention.
[0145] In an embodiment, an electrolyte of the present invention
comprises an anion receptor having the chemical structure AR1:
##STR00005##
wherein R.sub.1, R.sub.2 and R.sub.3 are independently selected
from the group consisting of alkyl, aromatic, ether, thioether,
heterocyclic, aryl or heteroaryl groups which are optionally
substituted with one or more halogens, including F, alkyl,
alkoxide, thiol, thioalkoxide, aromatic, ether or thioether.
[0146] In an embodiment, an electrolyte of the present invention
comprises a borate-based anion receptor compound having the
chemical structure AR2:
##STR00006##
wherein R.sub.4, R.sub.5 and R.sub.6 are selected from the group
consisting of alkyl, aromatic, heterocyclic, aryl or heteroaryl
groups which are optionally substituted with one or more halogens,
including F, alkyl, alkoxide, thiol, thioalkoxide, aromatic, ether
or thioether. In an embodiment R.sub.4, R.sub.5 and R.sub.6 are
identical. In an embodiment, each of R.sub.4, R.sub.5 and R.sub.6
are F-bearing moieties.
[0147] In an embodiment, an electrolyte of the present invention
comprises a phenyl boron-based anion receptor compound having the
chemical structure AR3:
##STR00007##
wherein R.sub.7 and R.sub.8 are selected from the group consisting
of alkyl, aromatic, heterocyclic, aryl or heteroaryl groups which
are optionally substituted with one or more halogens, including F,
alkyl, alkoxide, thiol, thioalkoxide, aromatic, ether or thioether.
In an embodiment R.sub.7 and R.sub.8 are identical. In an
embodiment, each of R.sub.7 and R.sub.8 are F-bearing moieties. In
an embodiment, R.sub.7 and R.sub.8 together from an aromatic,
including a phenyl that is optionally substituted, including
substituents that are F and substituents that are themselves
F-bearing moieties, as shown by chemical formula AR4:
##STR00008##
wherein X.sub.A and X.sub.B represent one or more hydrogens or
non-hydrogen ring substituents independently selected from the
group consisting of halogens, including F, alkyl, alkoxide, thiol,
thioalkoxide, ether, thioether. In an embodiment, at least one of
the substituents is a F-bearing moiety.
[0148] In an embodiment, an electrolyte of the present invention
comprises a Tris(hexafluoroisopropyl)borate (THFIB; MW=511.9 AMU)
anion receptor having the chemical structure AR5:
##STR00009##
or a Tris(2,2,2-trifluoroethyl) borate (TTFEB; MW=307.9 AMU) anion
receptor having the chemical structure AR6:
##STR00010##
or a Tris(pentafluorophenyl) borate (TPFPB; MW=511.98 AMU) anion
receptor having the chemical structure AR7:
##STR00011##
or a Bis(1,1,3,3,3-hexafluoroisopropyl) pentafluorophenyl boronate
(BHFIPFPB; MW -480.8 AMU) anion receptor having the structure
AR8:
##STR00012##
[0149] Anion receptors useful in electrolytes of present invention
include, but are not limited to, those having the formula selected
from the group consisting of: (CH.sub.3O).sub.3B,
(CF.sub.3CH.sub.2O).sub.3B, (C.sub.3F.sub.7CH.sub.2O).sub.3B,
[(CF.sub.3).sub.2CHO].sub.3B,
[(CF.sub.3).sub.2C(C.sub.6H.sub.5)O].sub.3B, ((CF.sub.3)CO).sub.3B,
(C.sub.6H.sub.5O).sub.3B, (FC.sub.6H.sub.4O).sub.3B,
(F.sub.2C.sub.6H.sub.3O).sub.3B, (F.sub.4C.sub.6HO).sub.3B,
(C.sub.6F.sub.5O).sub.3B, (CF.sub.3C.sub.6H.sub.4O).sub.3B,
[(CF.sub.3).sub.2C.sub.6H.sub.3O].sub.3B and
(C.sub.6F.sub.5).sub.3B.
[0150] Useful cation receptors in the present invention include,
but are not limited to, crown ethers, lariat ethers, metallacrown
ethers, calixcrowns (e.g., calyx(aza)crowns), tetrathiafulvalene
crowns, calixarenes, calix[4]arenediquinoes, tetrathiafulvalenes,
bis(calixcrown)tetrathiafulvalenes, and derivatives thereof.
[0151] The following references describe anion and/or cation
receptors useful in embodiments of the present invention, and are
hereby incorporated by reference to the extent not inconsistent
with the present disclosure: (1) Evidence for Cryptand-like
Behavior in Bibracchial Lariat Ether (BiBLE) Complexes Obtained
from X-ray Crystallography and Solution Thermodynamic Studies,
Kristin A. Arnold, Luis echeogoyen, Frank R. Fronczek, Richard D.
Grandour, Vinicent J. Gatto, Banita D. White, George W. Gokel, J.
Am. Chem. Soc., 109:3716-3721, 1987; (2)
Bis(calixcrown)tetrathiafulvalene Receptors. Maria-Jesus Blesa,
Bang-Tun Zhao, Magali Allain, Franck Le Derf, Marc Salle, Chem.
Eur. J. 12:1906-1914, 2006; (3) Studies on Calix(aza)crowns, II.
Synthesis of Novel Proximal Doubly Bridged Calix[4]arenes by
Intramolecular ring Closure of syn 1,3- and 1,2- to {acute over
(.omega.)}-Chloraolkylamides, Istavan Bitter, Alajos Grun, Gabor
Toth, Barbara Balazs, Gyula Horvath, Laszlo Toke, Tegrahedron
54:3857-3870, 1998; (4) Tetrathiafulvalene Crowns: Redox Switchable
Ligands, Franck Le Derf, Miloud Mazari, Nicolas Mercier, Eric
Levillain, Gaelle Trippe, Amedee Riou, Pascal Richomme, Jan Becher,
Javier Garin, Jesus Orduna, Nuria Gallego-Planas, Alain Gorgues,
Marc Salle, Chem. Eur. J. 7, 2:447-455, 2001; (5) Electrochemical
Behavior of Calix[4]arenediquinones and Their Cation Binding
Properties, Taek Dong Chung, Dongsuk Choi, Sun Kil Kang, Sang Swon
Lee, Suk-Kyu Chang, Hasuck Kim, Journal of Electroanalytical
Chemistry, 396:431-439, 1995; (6) Experimental Evidence for Alkali
Metal Cation-.pi. Interactions, George W. Gokel, Stephen L. De
Wall, Eric S. Meadows, Eur. J. Chem, 2967-2978, 2000; (7)
.pi.-Electron Properties of Large Condensed Polyaromatic
Hydrocarbons, S. E. Stein, R. L. Brown, J. Am. Chem. Soc.,
109:3721-3729, 1987; (8) Self-Assembled Organometallic
[12]Metallacrown-3 Complexes, Holger Piotrowski, Gerhard Hilt, Axel
Schulz, Peter Mayer, Kurt Polborn, Kay Severin, Chem. Eur. J., 7,
15:3197-3207, 2001; (9) First- and Second-sphere Coordination
Chemistry of Alkali Metal Crown Ether Complexes, Jonathan W. Steed,
Coordination Chemistry Reviews 215:171-221, 2001; (10) Alkali metal
ion complexes of functionalized calixarenes--competition between
pendent arm and anion bond to sodium; R. Abidi, L. Baklouti, J.
Harrowfield, A. Sobolev; J. Vicens, and A. White, Org. Biomol.
Chem, 2003, 1, 3144-3146; (11) Transition Metal and Organometallic
Anion Complexation Agents, Paul D. Beer, Elizabeth J. Hayes,
Coordination Chemistry Review, 240:167-189, 2003; (12) Versatile
Self-Complexing Compounds Based on Covalently Linked Donor-Acceptor
Cyclophanes, Yi Liu, Amar H. Flood, Ross M. Moskowitz, J. Fraser
Stoddart, Chem. Eur. J. 11:369-385, 2005; (13) Study of
Interactions of Various Ionic Species with Solvents Toward the
Design of Receptors, N. Jiten singh, Adriana C. Olleta, Anupriya
Kumar, Mina Park, Hai-Bo Yi, Indrajit Bandyopadhyay, Han Myoung
Lee, P. Tarakeshwar, Kwang S. Kim, Theor. Chem. Acc. 115:127-135,
2006; (14) A Calixarene-amide-tetrathiafulvalene Assembly for the
Electrochemical Detection of Anions, Bang-Tun Zhao, Maria-Jesus
Blesa, Nicolas Mercier, Franck Le Derf, Marc Salle, New J. Chem.
29:1164-1167, 2005.
STATEMENTS REGARDING INCORPORATION BY REFERENCE AND VARIATIONS
[0152] All references throughout this application, for example
patent documents including issued or granted patents or
equivalents; patent application publications; and non-patent
literature documents or other source material; are hereby
incorporated by reference herein in their entireties, as though
individually incorporated by reference, to the extent each
reference is at least partially not inconsistent with the
disclosure in this application (for example, a reference that is
partially inconsistent is incorporated by reference except for the
partially inconsistent portion of the reference).
[0153] The terms and expressions which have been employed herein
are used as terms of description and not of limitation, and there
is no intention in the use of such terms and expressions of
excluding any equivalents of the features shown and described or
portions thereof, but it is recognized that various modifications
are possible within the scope of the invention claimed. Thus, it
should be understood that although the present invention has been
specifically disclosed by preferred embodiments, exemplary
embodiments and optional features, modification and variation of
the concepts herein disclosed may be resorted to by those skilled
in the art, and that such modifications and variations are
considered to be within the scope of this invention as defined by
the appended claims. The specific embodiments provided herein are
examples of useful embodiments of the present invention and it will
be apparent to one skilled in the art that the present invention
may be carried out using a large number of variations of the
devices, device components, methods steps set forth in the present
description. As will be obvious to one of skill in the art, methods
and devices useful for the present methods can include a large
number of optional composition and processing elements and
steps.
[0154] When a group of substituents is disclosed herein, it is
understood that all individual members of that group and all
subgroups, including any isomers, enantiomers, and diastereomers of
the group members, are disclosed separately. When a Markush group
or other grouping is used herein, all individual members of the
group and all combinations and subcombinations possible of the
group are intended to be individually included in the disclosure.
When a compound is described herein such that a particular isomer,
enantiomer or diastereomer of the compound is not specified, for
example, in a formula or in a chemical name, that description is
intended to include each isomers and enantiomer of the compound
described individual or in any combination. Additionally, unless
otherwise specified, all isotopic variants of compounds disclosed
herein are intended to be encompassed by the disclosure. For
example, it will be understood that any one or more hydrogens in a
molecule disclosed can be replaced with deuterium or tritium.
Isotopic variants of a molecule are generally useful as standards
in assays for the molecule and in chemical and biological research
related to the molecule or its use. Methods for making such
isotopic variants are known in the art. Specific names of compounds
are intended to be exemplary, as it is known that one of ordinary
skill in the art can name the same compounds differently.
[0155] Many of the molecules disclosed herein contain one or more
ionizable groups [groups from which a proton can be removed (e.g.,
--COOH) or added (e.g., amines) or which can be quaternized (e.g.,
amines)]. All possible ionic forms of such molecules and salts
thereof are intended to be included individually in the disclosure
herein. With regard to salts of the compounds herein, one of
ordinary skill in the art can select from among a wide variety of
available counterions those that are appropriate for preparation of
salts of this invention for a given application. In specific
applications, the selection of a given anion or cation for
preparation of a salt may result in increased or decreased
solubility of that salt.
[0156] Every formulation or combination of components described or
exemplified herein can be used to practice the invention, unless
otherwise stated.
[0157] Whenever a range is given in the specification, for example,
a temperature range, a time range, or a composition or
concentration range, all intermediate ranges and subranges, as well
as all individual values included in the ranges given are intended
to be included in the disclosure. It will be understood that any
subranges or individual values in a range or subrange that are
included in the description herein can be excluded from the claims
herein.
[0158] All patents and publications mentioned in the specification
are indicative of the levels of skill of those skilled in the art
to which the invention pertains. References cited herein are
incorporated by reference herein in their entirety to indicate the
state of the art as of their publication or filing date and it is
intended that this information can be employed herein, if needed,
to exclude specific embodiments that are in the prior art. For
example, when composition of matter are claimed, it should be
understood that compounds known and available in the art prior to
Applicant's invention, including compounds for which an enabling
disclosure is provided in the references cited herein, are not
intended to be included in the composition of matter claims
herein.
[0159] As used herein, "comprising" is synonymous with "including,"
"containing," or "characterized by," and is inclusive or open-ended
and does not exclude additional, unrecited elements or method
steps. As used herein, "consisting of" excludes any element, step,
or ingredient not specified in the claim element. As used herein,
"consisting essentially of" does not exclude materials or steps
that do not materially affect the basic and novel characteristics
of the claim. In each instance herein any of the terms
"comprising", "consisting essentially of" and "consisting of" may
be replaced with either of the other two terms. The invention
illustratively described herein suitably may be practiced in the
absence of any element or elements, limitation or limitations which
is not specifically disclosed herein.
[0160] One of ordinary skill in the art will appreciate that
starting materials, biological materials, reagents, synthetic
methods, purification methods, analytical methods, assay methods,
and biological methods other than those specifically exemplified
can be employed in the practice of the invention without resort to
undue experimentation. All art-known functional equivalents, of any
such materials and methods are intended to be included in this
invention. The terms and expressions which have been employed are
used as terms of description and not of limitation, and there is no
intention that in the use of such terms and expressions of
excluding any equivalents of the features shown and described or
portions thereof, but it is recognized that various modifications
are possible within the scope of the invention claimed. Thus, it
should be understood that although the present invention has been
specifically disclosed by preferred embodiments and optional
features, modification and variation of the concepts herein
disclosed may be resorted to by those skilled in the art, and that
such modifications and variations are considered to be within the
scope of this invention as defined by the appended claims.
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