U.S. patent application number 16/419664 was filed with the patent office on 2020-09-24 for electrochemical device and electronic device including same.
The applicant listed for this patent is NINGDE AMPEREX TECHNOLOGY LIMITED. Invention is credited to Kefei WANG.
Application Number | 20200303767 16/419664 |
Document ID | / |
Family ID | 1000004124010 |
Filed Date | 2020-09-24 |
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United States Patent
Application |
20200303767 |
Kind Code |
A1 |
WANG; Kefei |
September 24, 2020 |
ELECTROCHEMICAL DEVICE AND ELECTRONIC DEVICE INCLUDING SAME
Abstract
This application relates to an electrochemical device and an
electronic device including the same. In particular, this
application provides an electrochemical device, including a
cathode, an anode and an electrolytic solution, where the anode
includes a carbon material and hydroxyalkyl methylcellulose, and
the electrolytic solution includes propionate. The electrochemical
device of this application has excellent cycle, storage and
low-temperature performance.
Inventors: |
WANG; Kefei; (Ningde City,
CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NINGDE AMPEREX TECHNOLOGY LIMITED |
Ningde City |
|
CN |
|
|
Family ID: |
1000004124010 |
Appl. No.: |
16/419664 |
Filed: |
May 22, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01M 4/60 20130101; H01M
10/0525 20130101; H01M 2004/027 20130101; H01M 10/0567 20130101;
H01M 10/0568 20130101; H01M 2004/021 20130101; H01M 4/583 20130101;
H01M 4/362 20130101 |
International
Class: |
H01M 10/0525 20060101
H01M010/0525; H01M 4/60 20060101 H01M004/60; H01M 4/36 20060101
H01M004/36; H01M 4/583 20060101 H01M004/583; H01M 10/0567 20060101
H01M010/0567; H01M 10/0568 20060101 H01M010/0568 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 18, 2019 |
CN |
201910203680.X |
Claims
1. An electrochemical device, comprising a cathode, an anode and an
electrolytic solution, wherein the anode comprises a carbon
material and hydroxyalkyl methylcellulose, and the electrolytic
solution comprises propionate.
2. The electrochemical device according to claim 1, wherein the
specific surface area of the carbon material is less than or equal
to about 3 m2/g.
3. The electrochemical device according to claim 2, wherein the
specific surface area of the carbon material is in a range of about
1.5 m2/g to about 2 m2/g.
4. The electrochemical device according to claim 1, wherein the
carbon material is selected from one or more of natural graphite
and artificial graphite.
5. The electrochemical device according to claim 1, wherein the
carbon material is artificial graphite.
6. The electrochemical device according to claim 1, wherein the
anode further comprises one or more of a silicon material, a
silicon-carbon composite material, a silicon-oxygen material, an
alloy material and a lithium-containing metal composite oxide
material.
7. The electrochemical device according to claim 1, wherein the
hydroxyalkyl methylcellulose is selected from one or more of
hydroxyalkyl methylcellulose sodium and hydroxyalkyl
methylcellulose lithium, and the alkyl has 1-8 carbon atoms.
8. The electrochemical device according to claim 1, wherein the
propionate is selected from compounds of Formula 1: ##STR00003##
wherein: R1 is ethyl or haloethyl, and R2 is alkyl or haloalkyl
having 1-6 carbon atoms.
9. The electrochemical device according to claim 1, wherein the
propionate is selected from one or more of the following: methyl
propionate, ethyl propionate, propyl propionate, butyl propionate,
amyl propionate, methyl halopropionate, ethyl halopropionate,
propyl halopropionate, butyl halopropionate and amyl
halopropionate.
10. The electrochemical device according to claim 9, wherein the
propionate is selected from one or more of ethyl propionate and
propyl propionate.
11. The electrochemical device according to claim 1, wherein the
content of the propionate is about 10% to about 65% based on the
total weight of the electrolytic solution.
12. The electrochemical device according to claim 1, wherein the
electrolytic solution further comprises an additive, and the
additive is selected from one or more of the following:
fluorocarbonate, carbon-carbon double bond-containing ethylene
carbonate, a sulfur-oxygen double bond-containing compound, a
compound having 2-4 cyano groups, a cyclic carboxylate, a cyclic
phosphoric anhydride, a carboxylic anhydride, a sulfonic anhydride
and a carboxylic sulfonic anhydride.
13. The electrochemical device according to claim 12, wherein the
additive is selected from a fluorocarbonate and a compound having
2-4 cyano groups.
14. The electrochemical device according to claim 12, wherein the
content of the additive is about 0.01% to about 15% based on the
total weight of the electrolytic solution.
15. The electrochemical device according to claim 13, wherein the
fluorocarbonate has the formula C.dbd.O(OR1)(OR2), wherein R1 and
R2 are each selected from alkyl or haloalkyl having 1-6 carbon
atoms, wherein at least one of R1 and R2 is selected from
fluoroalkyl having 1-6 carbon atoms, and R1 and R2 optionally form
a 5- to 7-membered ring along with the atoms to which they are
connected.
16. The electrochemical device according to claim 13, wherein the
fluorocarbonate is selected from one or more of the following:
fluoroethylene carbonate, cis 4,4-difluoroethylene carbonate, trans
4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate,
4-fluoro-4-methylethylene carbonate, 4-fluoro-5-methylethylene
carbonate, methyl trifluoromethyl carbonate, methyl trifluoroethyl
carbonate and ethyl trifluoroethyl carbonate.
17. The electrochemical device according to claim 16, wherein the
fluorocarbonate is fluoroethylene carbonate.
18. The electrochemical device according to claim 12, wherein the
content of the propionate is about 1.5 to about 30 times the
additive based on the total weight of the electrolyte.
19. The electrochemical device according to claim 1, wherein the
electrolytic solution further comprises one or more of the
following: LiPF6, LiBF4, LiPO2F2, LiSbF6, LiAsF6, LiC4F9SO3,
LiClO4, LiB(C2O4)2 and LiN(CxF2x+1SO2)(CyF2y+1SO2), wherein x and y
are integers of 1-5.
20. An electronic device, comprising an electrochemical device
having a cathode, an anode and an electrolytic solution, wherein
the anode comprises a carbon material and hydroxyalkyl
methylcellulose, and the electrolytic solution comprises
propionate.
Description
BACKGROUND
1. Technical Field
[0001] This application relates to the field of energy storage
technologies, and in particular to an electrochemical device and an
electronic device including the same, and more particularly to a
lithium-ion battery.
2. Description of the Related Art
[0002] With the development of technologies and the increasing
demand for mobile devices, the demand for electrochemical devices
has increased significantly. An electrochemical device with both
high energy density and excellent service life and cycle
performance is of primary research focus.
[0003] The theoretical capacity of an electrochemical device (e.g.,
a lithium-ion battery) may vary depending on the type of an anode
active material. As its number of cycles increases, a lithium-ion
battery will generally have a decrease in its charge/discharge
capacity, causing the deterioration in the performance of the
lithium-ion battery.
[0004] In view of this, it is indeed necessary to provide an
improved electrochemical device having excellent cycle, storage and
low-temperature performance and an electronic device including the
same.
SUMMARY
[0005] The embodiments of this application seek to resolve at least
one of the problems existing in the related art by providing an
electrochemical device and an electronic device including the
same.
[0006] In one embodiment, this application provides an
electrochemical device, including a cathode, an anode and an
electrolytic solution, where the anode includes a carbon material
and hydroxyalkyl methylcellulose, and the electrolytic solution
includes propionate.
[0007] According to the embodiments of this application, the
specific surface area of the carbon material is less than or equal
to about 3 m.sup.2/g. In some embodiments, the specific surface
area of the carbon material is less than or equal to about 2.5
m.sup.2/g. In some embodiments, the specific surface area of the
carbon material is less than or equal to about 2 m.sup.2/g. In some
embodiments, the specific surface area of the carbon material is in
the range of about 1.5 m.sup.2/g to about 2 m.sup.2/g.
[0008] According to the embodiments of this application, the carbon
material is selected from one or more of natural graphite and
artificial graphite.
[0009] According to the embodiments of this application, the anode
further includes one or more of a silicon material, a
silicon-carbon composite material, a silicon-oxygen material, an
alloy material and a lithium-containing metal composite oxide
material.
[0010] According to the embodiments of this application, the
hydroxyalkyl methylcellulose is selected from one or more of
hydroxyalkyl methylcellulose sodium and hydroxyalkyl
methylcellulose lithium, and the alkyl has 1-8 carbon atoms.
[0011] According to the embodiments of this application, the
propionate is selected from compounds of Formula 1:
##STR00001##
[0012] where:
[0013] R.sup.1 is ethyl or haloethyl, and
[0014] R.sup.2 is alkyl or haloalkyl having 1-6 carbon atoms.
[0015] According to the embodiments of this application, the
propionate is selected from one or more of the following: methyl
propionate, ethyl propionate, propyl propionate, butyl propionate,
amyl propionate, methyl halopropionate, ethyl halopropionate,
propyl halopropionate, butyl halopropionate and amyl
halopropionate.
[0016] According to the embodiments of this application, the
content of the propionate is about 10%-about 65% based on the total
weight of the electrolytic solution. In some embodiments, the
content of the propionate is about 15%-about 60% based on the total
weight of the electrolytic solution. In some embodiments, the
content of the propionate is about 30%-about 50% based on the total
weight of the electrolytic solution. In some embodiments, the
content of the propionate is about 30%-about 40% based on the total
weight of the electrolytic solution.
[0017] According to the embodiments of this application, the
electrolytic solution further includes an additive.
[0018] According to the embodiments of this application, the
additive is selected from one or more of the following:
fluorocarbonate, carbon-carbon double bond-containing ethylene
carbonate, a sulfur-oxygen double bond-containing compound, a
compound having 2-4 cyano groups, a cyclic carboxylate, a cyclic
phosphoric anhydride, a carboxylic anhydride, a sulfonic anhydride
and a carboxylic sulfonic anhydride.
[0019] According to the embodiments of this application, the
content of the additive is about 0.01%-about 15% based on the total
weight of the electrolytic solution. In some embodiments, the
content of the additive is about 0.1%-about 10% based on the total
weight of the electrolytic solution. In some embodiments, the
content of the additive is about 1%-about 5% based on the total
weight of the electrolytic solution.
[0020] According to the embodiments of this application, the
fluorocarbonate has the formula C.dbd.O(OR.sub.1)(OR.sub.2), where
R.sub.1 and R.sub.2 are each selected from alkyl or haloalkyl
having 1-6 carbon atoms, where at least one of R.sub.1 and R.sub.2
is selected from fluoroalkyl having 1-6 carbon atoms, and R.sub.1
and R.sub.2 optionally form a 5- to 7-membered ring along with the
atoms to which they are connected.
[0021] According to the embodiments of this application, the
fluorocarbonate is selected from one or more of the following:
fluoroethylene carbonate, cis 4,4-difluoroethylene carbonate, trans
4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate,
4-fluoro-4-methylethylene carbonate, 4-fluoro-5-methylethylene
carbonate, methyl trifluoromethyl carbonate, methyl trifluoroethyl
carbonate and ethyl trifluoroethyl carbonate.
[0022] According to the embodiments of this application, the
content of the propionate is about 1.5-about 30 times the additive
based on the total weight of the electrolytic solution. In some
embodiments, the content of the propionate is about 1.5-about 20
times the additive based on the total weight of the electrolytic
solution. In some embodiments, the content of the propionate is
about 2-about 20 times the additive based on the total weight of
the electrolytic solution. In some embodiments, the content of the
propionate is about 5-about 20 times the additive based on the
total weight of the electrolytic solution.
[0023] According to the embodiments of this application, the
electrolytic solution further includes one or more of the
following: LiPF.sub.6, LiBF.sub.4, LiPO.sub.2F.sub.2, LiSbF.sub.6,
LiAsF.sub.6, LiC.sub.4F.sub.9SO.sub.3, LiClO.sub.4,
LiB(C.sub.2O.sub.4).sub.2 and
LiN(C.sub.xF.sub.2x+1SO.sub.2)(C.sub.yF.sub.2y+1SO.sub.2), where x
and y are integers of 1-5.
[0024] In another embodiment, this application provides an
electronic device including an electrochemical device as described
above.
[0025] Additional aspects and advantages of the embodiments of this
application will be described or shown in the following description
or interpreted by implementing the embodiments of this
application.
DETAILED DESCRIPTION
[0026] Embodiments of this application are described in detail
below. The embodiments of this application should not be construed
as limiting this application.
[0027] Unless otherwise expressly indicated, the following terms
used herein have the meanings indicated below.
[0028] The term "about" is used to describe and explain minor
changes. When being used in combination with an event or
circumstance, the term may refer to an example in which the event
or circumstance occurs precisely, and an example in which the event
or circumstance occurs approximately. For example, when used in
conjunction with a numerical value, the terms may refer to a
variation range that is less than or equal to .+-.10% of the
numerical value, such as less than or equal to .+-.5%, less than or
equal to .+-.4%, less than or equal to .+-.3%, less than or equal
to .+-.2%, less than or equal to .+-.1%, less than or equal to
.+-.0.5%, less than or equal to .+-.0.1%, or less than or equal to
.+-.0.05%. In addition, amounts, ratios and other numerical values
are sometimes presented herein in a range format. It should be
appreciated that such range formats are for convenience and
conciseness, and should be flexibly understood as comprising not
only values explicitly specified to range constraints, but also all
individual values or sub-ranges within the ranges, like explicitly
specifying each value and each sub-range.
[0029] A list of items connected by the term "one of" or similar
terms may mean any of the listed items. For example, if items A and
B are listed, then the phrase "one of A and B" means only A or only
B. In another example, if items A, B, and C are listed, then the
phrase "one of A, B and C" means only A; only B; or only C. The
item A may include a single component or multiple components. The
item B may include a single component or multiple components. The
item C may include a single component or multiple components.
[0030] A list of items connected by the term "one or more of" or
similar terms may mean any combination of the listed items. For
example, if items A and B are listed, then the phrase "one or more
of A and B" means only A; only B; or A and B. In another example,
if items A, B and C are listed, then the phrase "one or more of A,
B and C" means only A; or only B; only C; A and B (excluding C); A
and C (excluding B); B and C (excluding A); or all of A, B and C.
The item A may include a single component or multiple components.
The item B may include a single component or multiple components.
The item C may include a single component or multiple
components.
[0031] The term "alkyl" refers to a linear or branched chained
saturated hydrocarbon structure having 1 to 20 carbon atoms. In
some embodiments, the alkyl has 1 to 8 carbon atoms. In some
embodiments, the alkyl has 1 to 6 carbon atoms. When an alkyl
having a specific carbon number is specified, it is intended to
cover all geometric isomers having that carbon number; therefore,
for example, "butyl" means to include n-butyl, sec-butyl, isobutyl,
tert-butyl and cyclobutyl; and "propyl" includes n-propyl,
isopropyl and cyclopropyl. Examples of alkyl include, but are not
limited to, methyl, ethyl, n-propyl, isopropyl, cyclopropyl,
n-butyl, isobutyl, sec-butyl, tert-butyl, cyclobutyl, n-pentyl,
isoamyl, neopentyl, cyclopentyl, methylcyclopentyl,
ethylcyclopentyl, n-hexyl, isohexyl, cyclohexyl, n-heptyl, octyl,
cyclopropyl, cyclobutyl, norbornyl and the like.
[0032] The term "hydroxyalkyl" refers to an alkyl group as defined
above, where at least one hydrogen atom is replaced by a hydroxy
group. Exemplary hydroxyalkyl groups include, but are not limited
to, hydroxymethyl, hydroxyethyl (where the hydroxy group is at the
1- or 2-position), hydroxypropyl (where the hydroxy group is at 1-,
2- or 3-position), hydroxybutyl (where the hydroxy group is at the
1-, 2-, 3- or 4-position), hydroxypentyl (where the hydroxy group
is at the 1-, 2-, 3-, 4- or 5-position)), hydroxyhexyl (where the
hydroxy group is at the 1-, 2-, 3-, 4-, 5- or 6-position),
1,2-dihydroxyethyl and the like.
[0033] As used herein, the content of each component is a mass
percentage based on the total weight of the electrolytic
solution.
[0034] The theoretical capacity of an electrochemical device (e.g.,
a lithium-ion battery) may vary depending on the type of the anode
active material. As the number of cycles increases, lithium-ion
batteries generally have a decrease in charge/discharge capacity.
This is because the volume change of the electrodes during charging
and discharging of the lithium-ion battery causes separation
between the electrode active materials or between the electrode
active material and the electrode current collector, resulting in
the electrode active material not functioning well. In addition,
during the charging/discharging of a lithium-ion battery, a change
in electrode volume causes deformation of the electrode (for
example, the interface film of the solid electrolyte is damaged),
thereby exacerbating the consumption of lithium in the electrolyte
solution, so that the electrode active material and the lithium-ion
battery are deteriorated. The use of an adhesive having low
adhesion (for example, carboxymethylcellulose) is one of the main
causes of deterioration in performance of the lithium-ion
battery.
[0035] This application resolves this problem by using specific
electrode materials. In the charging/discharging process of the
electrochemical device of this application, even if the electrode
volume changes, the electrode material has a strong adhesion due to
the inclusion of a specific adhesive, which can improve the
structural stability of the electrode and prevent deterioration
caused by separation of the active material, thereby improving the
performance of the electrochemical device.
[0036] On the other hand, this application uses a specific
electrode material in combination with a specific electrolytic
solution to significantly suppress the decomposition reaction of
the electrolytic solution after high-temperature charging, thereby
improving the performance of the electrochemical device.
[0037] In one embodiment, this application provides an
electrochemical device, including a cathode, an anode and an
electrolytic solution as described below. In some embodiments, the
electrochemical device further includes a separator disposed
between the cathode and the anode.
[0038] 1. Anode
[0039] The anode includes an anode current collector and an anode
active material layer disposed on one or two surfaces of the anode
current collector.
[0040] The anode current collector includes an anode conductive
material. In some embodiments, the anode current collector
includes, but is not limited to, copper, nickel and stainless
steel. In some embodiments, the surface of the anode current
collector is roughened, and the roughened surface can improve the
adhesion of the anode active material. In some embodiments, the
roughened anode current collector includes, but is not limited to,
electrolytic copper foil.
[0041] The anode active material layer includes an anode active
material and an anode adhesive. The anode active material layer may
be one or more layers. Each of the plurality of layers of the anode
active material may include the same or different anode active
materials. The anode active material is any material capable of
deintercalating metal ions such as lithium ions. In some
embodiments, the chargeable capacity of the anode active material
is greater than the discharge capacity of a cathode active material
to prevent the lithium metal from unintentionally precipitating on
the anode during charging.
[0042] One of the main features of the electrochemical device of
this application is that one or more carbon materials are included
in the anode as the anode active material.
[0043] In some embodiments, the specific surface area of the carbon
material is less than or equal to about 3 m.sup.2/g. In some
embodiments, the specific surface area of the carbon material is
less than or equal to about 2.5 m.sup.2/g. In some embodiments, the
specific surface area of the carbon material is less than or equal
to about 2 m.sup.2/g. In some embodiments, the specific surface
area of the carbon material is in the range of about 1.5 m.sup.2/g
to about 2 m.sup.2/g. Combining the above-described carbon material
having a particular specific surface area with a specific type of
anode adhesive (for example, hydroxyalkyl methylcellulose) and an
electrolytic solution solvent (for example, propionate) can
significantly suppress the decomposition reaction of the
electrolytic solution after high-temperature charging, thereby
improving the performance of the electrochemical device.
[0044] In some embodiments, the carbon material is selected from
one or more of natural graphite and artificial graphite. In some
embodiments, the carbon material includes artificial graphite.
[0045] In some embodiments, the shape of the carbon material
includes, but is not limited to, fibrous, spherical, granular, and
scaly.
[0046] In some embodiments, the anode further includes one or more
of a silicon material, a silicon-carbon composite material, a
silicon-oxygen material, an alloy material and a lithium-containing
metal composite oxide material. In some embodiments, the anode
active material layer further includes other types of anode active
materials. For example, one or more materials include metal
elements and metalloid elements capable of forming an alloy with
lithium. Examples of the metal elements and metalloid elements
include, but are not limited to, Mg, B, Al, Ga, In, Si, Ge, Sn, Pb,
Bi, Cd, Ag, Zn, Hf, Zr, Y, Pd and Pt. In particular, Si, Sn, or a
combination thereof may be used because Si and Sn have excellent
capacity to deintercalate lithium ions, and can provide a high
energy density for an electrochemical device. In some embodiments,
anode active materials of other types may further include one or
more of metal oxides and a high-molecular compound. In some
embodiments, the metal oxides include, but are not limited to, iron
oxide, ruthenium oxide and molybdenum oxide. In some embodiments,
the high-molecular compound includes, but is not limited to,
polyacetylene, polyaniline and polypyrrole.
[0047] Another main feature of the electrochemical device of this
application is that hydroxyalkyl methylcellulose is included in the
anode as an anode adhesive. The hydroxyalkyl methylcellulose has
excellent adhesion and dispersibility with the carbon material.
[0048] In some embodiments, the hydroxyalkyl methylcellulose is
selected from one or more of hydroxyalkyl methylcellulose sodium
and hydroxyalkyl methylcellulose lithium, and the alkyl has 1-8
carbon atoms. In some embodiments, the hydroxyalkyl methylcellulose
includes, but is not limited to, one or more of hydroxyalkyl
methylcellulose sodium and hydroxyalkyl methylcellulose lithium,
where the alkyl includes methyl, ethyl, propyl or butyl. The use of
the hydroxyalkyl methylcellulose in combination with a specific
type of electrolytic solution solvent (for example, propionate) can
significantly suppress the increase in thickness of the
electrochemical device after high-temperature charging.
[0049] In some embodiments, the anode adhesive further includes one
or more of styrene-butadiene rubber, fluororubber and ethylene
propylene diene copolymer.
[0050] In some embodiments, the anode active material layer further
includes other materials, for example, an anode conductive agent.
In some embodiments, the anode conductive agent includes one or
more of a conductive metal material and a conductive polymer. In
some embodiments, the anode conductive agent includes one or more
of a carbon material or the like. In some embodiments, the carbon
material includes, but is not limited to, graphite, carbon black,
acetylene black and Ketjen black.
[0051] 2. Electrolytic Solution
[0052] The electrolytic solution used in the electrochemical device
of this application includes an electrolyte and a solvent that
dissolves the electrolyte. In some embodiments, the electrolytic
solution used in the electrochemical device of this application
further includes an additive.
[0053] (1) Solvent
[0054] One of the main features of the electrochemical device of
this application is that the electrolytic solution includes
propionate as a solvent. In the case where the anode active
material is a carbon material and the anode adhesive is
hydroxypropyl methylcellulose, the use of propionate as a solvent
for the electrolytic solution can improve the chemical stability of
the electrolytic solution and inhibit the gas production phenomenon
of the electrochemical device after high-temperature charging,
thereby reducing the thickness expansion of the electrochemical
device.
[0055] In some embodiments, the propionate is selected from
compounds of Formula 1:
##STR00002##
[0056] where:
[0057] R.sup.1 is ethyl or haloethyl, and
[0058] R.sup.2 is alkyl or haloalkyl having 1-6 carbon atoms.
[0059] In some embodiments, the propionate includes, but is not
limited to, methyl propionate, ethyl propionate, propyl propionate,
butyl propionate, amyl propionate, methyl halopropionate, ethyl
halopropionate, propyl halopropionate, butyl halopropionate and
amyl halopropionate. In some embodiments, the halo group in the
methyl halopropionate, ethyl halopropionate, propyl halopropionate,
butyl halopropionate and amyl halopropionate is selected from one
or more of a fluoro group (--F), a chloro group (--Cl), a bromo
group (--Br) and an iodo group (--I). In some embodiments, the halo
group is a fluoro group (--F), which can achieve a more excellent
effect.
[0060] In some embodiments, the content of the propionate is about
10%-about 65% based on the total weight of the electrolytic
solution. In some embodiments, the content of the propionate is
about 15%-about 60% based on the total weight of the electrolytic
solution. In some embodiments, the content of the propionate is
about 30%-about 50% based on the total weight of the electrolytic
solution. In some embodiments, the content of the propionate is
about 30%-about 40% based on the total weight of the electrolytic
solution. A more excellent effect can be achieved by using the
propionate having the above content.
[0061] In some embodiments, the electrolytic solution further
includes any non-aqueous solvent known in the prior art as a
solvent of the electrolytic solution.
[0062] In some embodiments, the non-aqueous solvent includes, but
is not limited to, one or more of the following: cyclic carbonate,
chained carbonate, cyclic carboxylate, chained carboxylate, cyclic
ether, chained ether, phosphorus-containing organic solvent, a
sulfur-containing organic solvent and an aromatic
fluorine-containing solvent.
[0063] In some embodiments, the cyclic carbonate includes, but is
not limited to, one or more of the following: ethylene carbonate
(EC), propylene carbonate (PC) and butylene carbonate. In some
embodiments, the cyclic carbonate has 3-6 carbon atoms.
[0064] In some embodiments, the chained carbonate includes, but is
not limited to, one or more of the following: dimethyl carbonate,
ethyl methyl carbonate, diethyl carbonate (DEC), methyl n-propyl
carbonate, ethyl n-propyl carbonate, di-n-propyl carbonate and
other chained carbonate, as chained carbonate substituted with
fluorine, for example, bis(fluoromethyl)carbonate,
bis(difluoromethyl)carbonate, bis(trifluoromethyl)carbonate,
bis(2-fluoroethyl)carbonate, bis(2,2-difluoroethyl)carbonate,
bis(2,2,2-trifluoroethyl)carbonate, 2-fluoroethyl methyl carbonate,
2,2-difluoroethyl methyl carbonate and 2,2,2-trifluoroethyl methyl
carbonate.
[0065] In some embodiments, the cyclic carboxylate includes, but is
not limited to, one or more of .gamma.-butyrolactone and
.gamma.-valerolactone. In some embodiments, a portion of the
hydrogen atoms of the cyclic carboxylate can be substituted with
fluorine.
[0066] In some embodiments, the chained carboxylate includes, but
is not limited to, one or more of the following: methyl acetate,
ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate,
sec-butyl acetate, isobutyl acetate, tert-butyl acetate, methyl
propionate, ethyl propionate, propyl propionate, isopropyl
propionate, methyl butyrate, ethyl butyrate, propyl butyrate,
methyl isobutyrate, ethyl isobutyrate, methyl valerate, ethyl
valerate, methyl pivalate and ethyl pivalate. In some embodiments,
a portion of the hydrogen atoms of the chained carboxylate can be
substituted with fluorine. In some embodiments, the
fluorine-substituted chained carboxylate, includes, but is not
limited to, methyl trifluoroacetate, ethyl trifluoroacetate, propyl
trifluoroacetate, butyl trifluoroacetate and 2,2,2-trifluoroethyl
trifluoroacetate.
[0067] In some embodiments, the cyclic ether includes, but is not
limited to, one or more of the following: tetrahydrofuran,
2-methyltetrahydrofuran, 1,3-dioxolane, 2-methyl-1,3-dioxolane,
4-methyl-1,3-dioxolane, 1,3-dioxane, 1,4-dioxane and
dimethoxypropane.
[0068] In some embodiments, the chained ether includes, but is not
limited to, one or more of the following: dimethoxymethane,
1,1-dimethoxyethane, 1,2-dimethoxyethane, diethoxymethane,
1,1-diethoxyethane, 1,2-diethoxyethane, ethoxymethoxymethane,
1,1-ethoxymethoxyethane and 1,2-ethoxymethoxyethane.
[0069] In some embodiments, the phosphorus-containing organic
solvent includes, but is not limited to, one or more of the
following: trimethyl phosphate, triethyl phosphate, dimethyl ethyl
phosphate, methyl diethyl phosphate, ethidene methyl phosphate,
ethidene ethyl phosphate, triphenyl phosphate, trimethyl phosphite,
triethyl phosphite, triphenyl phosphite, tris(2,2,2-trifluoroethyl)
phosphate and tris(2,2,3,3,3-pentafluoropropyl) phosphate.
[0070] In some embodiments, the sulfur-containing organic solvent
includes, but is not limited to, one or more of the following:
sulfolane, 2-methylsulfolane, 3-methylsulfolane, dimethyl sulfone,
diethyl sulfone, ethyl methyl sulfone, methyl propyl sulfone,
dimethyl sulfoxide, methyl methanesulfonate, ethyl
methanesulfonate, methyl ethanesulfonate, ethyl ethanesulfonate,
dimethyl sulfate, diethyl sulfate and dibutyl sulfate. In some
embodiments, a portion of the hydrogen atoms of the
sulfur-containing organic solvent can be substituted with
fluorine.
[0071] In some embodiments, the aromatic fluorine-containing
solvent includes, but is not limited to, one or more of the
following: fluorobenzene, difluorobenzene, trifluorobenzene,
tetrafluorobenzene, pentafluorobenzene, hexafluorobenzene and
trifluoromethylbenzene.
[0072] In some embodiments, the solvent used in the electrolytic
solution of this application includes cyclic carbonate, chained
carbonate, cyclic carboxylate, chained carboxylate and combinations
thereof. In some embodiments, the solvent used in the electrolytic
solution of this application includes an organic solvent selected
from the group consisting of ethylene carbonate, propylene
carbonate, diethyl carbonate, ethyl propionate, propyl propionate,
n-propyl acetate, ethyl acetate and combinations thereof. In some
embodiments, the solvent used in the electrolytic solution of this
application includes ethylene carbonate, propylene carbonate,
diethyl carbonate, ethyl propionate, propyl propionate,
.gamma.-butyrolactone and combinations thereof.
[0073] After the chained carboxylate and/or the cyclic carboxylate
are added to the electrolytic solution, the chained carboxylate
and/or the cyclic carboxylate can form a passivation film on the
surface of the electrode, thereby improving the capacity retention
rate after the intermittent charging cycle of the electrochemical
device. In some embodiments, the electrolytic solution contains
about 1 wt %-about 60 wt % of chained carboxylate, cyclic
carboxylate and combinations thereof. In some embodiments, the
electrolytic solution contains about 1 wt %-about 60 wt %, about 10
wt %-about 60 wt %, about 10 wt %-about 50 wt % or about 20 wt
%-about 50 wt % of ethyl propionate, propyl propionate,
.gamma.-butyrolactone and combinations thereof. In some
embodiments, the electrolytic solution contains about 1 wt %-about
60 wt %, about 10 wt %-about 60 wt %, about 20 wt %-about 50 wt %,
about 20 wt %-about 40 wt % or about 30 wt % of propyl
propionate.
[0074] (2) Additive
[0075] In some embodiments, the additive includes, but is not
limited to, one or more of the following: fluorocarbonate,
carbon-carbon double bond-containing ethylene carbonate, a
sulfur-oxygen double bond-containing compound, a compound having
2-4 cyano groups, and acid anhydrides.
[0076] In some embodiments, the content of the additive is about
0.01%-about 15% based on the total weight of the electrolytic
solution. In some embodiments, the content of the additive is about
0.1%-about 10% based on the total weight of the electrolytic
solution. In some embodiments, the content of the additive is about
1%-about 5% based on the total weight of the electrolytic
solution.
[0077] According to the embodiments of this application, the
content of the propionate is about 1.5-about 30 times the additive
based on the total weight of the electrolytic solution. In some
embodiments, the content of the propionate is about 1.5-about 20
times the additive based on the total weight of the electrolytic
solution. In some embodiments, the content of the propionate is
about 2-about 20 times the additive based on the total weight of
the electrolytic solution. In some embodiments, the content of the
propionate is about 5-about 20 times the additive based on the
total weight of the electrolytic solution.
[0078] Fluorocarbonate
[0079] In some embodiments, the additive includes one or more
fluorocarbonate. When the lithium-ion battery is
charged/discharged, the fluorocarbonate can act together with the
propionate to form a stable protective film on the surface of the
anode, thereby suppressing the decomposition reaction of the
electrolytic solution.
[0080] In some embodiments, the fluorocarbonate has the formula
C.dbd.O(OR.sub.1)(OR.sub.2), where R.sub.1 and R.sub.2 are each
selected from alkyl or haloalkyl having 1-6 carbon atoms, where at
least one of R.sub.1 and R.sub.2 is selected from fluoroalkyl
having 1-6 carbon atoms, and R.sub.1 and R.sub.2 optionally form a
5- to 7-membered ring along with the atoms to which they are
connected.
[0081] In some embodiments, the fluorocarbonate includes, but is
not limited to, one or more of the following: fluoroethylene
carbonate, cis 4,4-difluoroethylene carbonate, trans
4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate,
4-fluoro-4-methylethylene carbonate, 4-fluoro-5-methylethylene
carbonate, methyl trifluoromethyl carbonate, methyl trifluoroethyl
carbonate and ethyl trifluoroethyl carbonate.
[0082] Carbon-Carbon Double Bond-Containing Ethylene Carbonate
[0083] In some embodiments, the carbon-carbon double
bond-containing ethylene carbonate includes, but is not limited to,
one or more of the following: vinylene carbonate, methyl vinylene
carbonate, ethyl vinylene carbonate, 1,2-dimethylvinylene
carbonate, 1,2-diethylvinylene carbonate, fluorovinylene carbonate,
trifluoromethyl vinylene carbonate; vinyl ethylene carbonate,
1-methyl-2-vinylethylene carbonate, 1-ethyl-2-vinylethylene
carbonate, 1-n-propyl-2-vinylethylene carbonate,
1-methyl-2-vinylethylene carbonate, 1,1-divinylethylene carbonate,
1,2-divinylethylene carbonate, 1,1-dimethyl-2-methylene ethylene
carbonate and 1,1-diethyl-2-methylene ethylene carbonate. In some
embodiments, the carbon-carbon double bond-containing ethylene
carbonate includes vinylene carbonate, which is easy to obtain and
can achieve a more excellent effect.
[0084] Sulfur-Oxygen Double Bond-Containing Compound
[0085] In some embodiments, the sulfur-oxygen double
bond-containing compound includes, but is not limited to, one or
more of the following: cyclic sulfate, chained sulfate, chained
sulfonate, cyclic sulfonate, chained sulfite and cyclic
sulfite.
[0086] In some embodiments, the cyclic sulfate includes, but is not
limited to, one or more of the following: 1,2-ethanediol sulfate,
1,2-propanediol sulfate, 1,3-propanediol sulfate, 1,2-butanediol
sulfate, 1,3-butanediol sulfate, 1,4-butanediol sulfate,
1,2-pentanediol sulfate, 1,3-pentanediol sulfate, 1,4-pentanediol
sulfate and 1,5-pentanediol sulfate.
[0087] In some embodiments, the chained sulfate includes, but is
not limited to, one or more of the following: dimethyl sulfate,
ethyl methyl sulfate and diethyl sulfate.
[0088] In some embodiments, the chained sulfonate includes, but is
not limited to, one or more of the following: fluorosulfonate such
as methyl fluorosulfonate and ethyl fluorosulfonate, methyl
methanesulfonate, ethyl methanesulfonate, butyl dimethanesulfonate,
methyl 2-(methylsulfonyloxy)propionate and ethyl
2-(methylsulfonyloxy)propionate.
[0089] In some embodiments, the cyclic sulfonate includes, but is
not limited to, one or more of the following: 1,3-propane sultone,
1-fluoro-1,3-propane sultone, 2-fluoro-1,3-propane sultone,
3-fluoro-1,3-propane sultone, 1-methyl-1,3-propane sultone,
2-methyl-1,3-propane sultone, 3-methyl-1,3-propane sultone,
1-propene-1,3-sultone, 2-propene-1,3-sultone,
1-fluoro-1-propene-1,3-sulfonate, 2-fluoro-1-propene-1,3-sultone,
3-fluoro-1-propene-1,3-sultone, 1-fluoro-2-propene-1,3-sultone,
2-fluoro-2-propene-1,3-sultone, 3-fluoro-2-propene-1,3-sultone,
1-methyl-1-propene-1,3-sultone, 2-methyl-1-propene-1,3-sultone,
3-methyl-1-propene-1,3-sultone, 1-methyl-2-propene-1,3-sultone,
2-methyl-2-propene-1,3-sultone, 3-methyl-2-propene-1,3-sultone,
1,4-butane sultone, 1,5-pentane sultone, methylene
methanedisulfonate and ethylene methanedisulfonate.
[0090] In some embodiments, the chained sulfite includes, but is
not limited to, one or more of the following: dimethyl sulfite,
ethyl methyl sulfite and diethyl sulfite.
[0091] In some embodiments, the cyclic sulfite includes, but is not
limited to, one or more of the following: 1,2-ethanediol sulfite,
1,2-propanediol sulfite, 1,3-propanediol sulfite, 1,2-butanediol
sulfite, 1,3-butanediol sulfite, 1,4-butanediol sulfite,
1,2-pentanediol sulfite, 1,3-pentanediol sulfite, 1,4-pentanediol
sulfite and 1,5-pentanediol sulfite.
[0092] Compound Having 2-4 Cyano Groups
[0093] In some embodiments, the compound having 2-4 cyano groups
includes, but is not limited to, one or more of a dinitrile
compound, a trinitrile compound and a tetranitrile compound.
[0094] In some embodiments, the compound having 2-4 cyano groups
includes, but is not limited to, one or more of the following:
succinonitrile, glutaronitrile, adiponitrile, 1,5-dicyanopentane,
1,6-dicyanohexane, tetramethyl succinonitrile,
2-methylglutaronitrile, 2,4-dimethylglutaronitrile,
2,2,4,4-tetramethylglutaronitrile, 1,4-dicyanopentane,
1,4-dicyanopentane, 1,2-dicyanobenzene, 1,3-dicyanobenzene,
1,4-dicyanobenzene, ethylene glycol bis(propionitrile)ether,
3,5-dioxa-pimelonitrile, 1,4-bis(cyanoethoxy)butane, diethylene
glycol bis(2-cyanoethyl) ether, triethylene glycol
bis(2-cyanoethyl) ether, tetraethylene glycol bis(2-cyanoethyl)
ether, 1,3-bis(2-cyanoethoxy)propane, 1,4-bis(2-cyanoethoxy)butane,
1,5-bis(2-cyanoethoxy)pentane, ethylene glycol bis(4-cyanobutyl)
ether, 1,4-dicyano-2-butene, 1,4-dicyano-2-methyl-2-butene,
1,4-dicyano-2-ethyl-2-butene, 1,4-dicyano-2,3-dimethyl-2-butene,
1,4-dicyano-2,3-diethyl-2-butene, 1,6-dicyano-3-hexene,
1,6-dicyano-2-methyl-3-hexene, 1,3,5-pentanetricarbonitrile,
1,2,3-propanetricarbonitrile, 1,3,6-hexanetricarbonitrile,
1,2,6-hexanetricarbonitrile, 1,2,3-tris(2-cyanoethoxy)propane,
1,2,4-tris(2-cyanoethoxy)butane,
1,1,1-tris(cyanoethoxymethylene)ethane,
1,1,1-tris(cyanoethoxymethylene)propane,
3-methyl-1,3,5-tris(cyanoethoxy)pentane,
1,2,7-tris(cyanoethoxy)heptane, 1,2,6-tris(cyanoethoxy)hexane and
1,2,5-tris(cyanoethoxy)pentane.
[0095] Acid Anhydride
[0096] In some embodiments, the acid anhydride includes, but is not
limited to, one or more of cyclic phosphoric anhydride, carboxylic
anhydride, disulfonic anhydride and carboxylic sulfonic anhydride.
In some embodiments, the cyclic phosphoric anhydride includes, but
is not limited to, one or more of trimethylphosphoric acid cyclic
anhydride, triethylphosphoric acid cyclic anhydride and
tripropylphosphoric acid cyclic anhydride. In some embodiments, the
carboxylic anhydride includes, but is not limited to, one or more
of succinic anhydride, glutaric anhydride and maleic anhydride. In
some embodiments, the disulfonic anhydride includes, but is not
limited to, one or more of ethane disulfonic anhydride and propane
disulfonic anhydride. In some embodiments, the carboxylic sulfonic
anhydride includes, but is not limited to, one or more of
sulfobenzoic anhydride, sulfopropionic anhydride and sulfobutyric
anhydride.
[0097] In some embodiments, the additive is a combination of
fluorocarbonate and carbon-carbon double bond-containing ethylene
carbonate. In some embodiments, the additive is a combination of
fluorocarbonate and a sulfur-oxygen double bond-containing
compound. In some embodiments, the additive is a combination of
fluorocarbonate and a compound having 2-4 cyano groups. In some
embodiments, the additive is a combination of fluorocarbonate and
cyclic carboxylate. In some embodiments, the additive is a
combination of fluorocarbonate and cyclic phosphoric anhydride. In
some embodiments, the additive is a combination of fluorocarbonate
and carboxylic anhydride. In some embodiments, the additive is a
combination of fluorocarbonate and sulfonic anhydride. In some
embodiments, the additive is a combination of fluorocarbonate and
carboxylic sulfonic anhydride.
[0098] (3) Electrolyte
[0099] The electrolyte used in the electrolytic solution of this
application is not limited, and may be any electrolyte known in the
prior art. In some embodiments, the electrolyte includes, but is
not limited to, one or more of the following: inorganic lithium
salts, such as LiClO.sub.4, LiAsF.sub.6, LiPF6, LiBF.sub.4,
LiSbF.sub.6, LiSO.sub.3F, LiN(FSO.sub.2).sub.2, etc.;
fluorine-containing organic lithium salts, such as
LiCF.sub.3SO.sub.3, LiN(FSO.sub.2)(CF.sub.3SO.sub.2),
LiN(CF.sub.3SO.sub.2).sub.2, LiN(C.sub.2F.sub.5SO.sub.2).sub.2,
cyclic lithium 1,3-hexafluoropropane disulfonimide, cyclic lithium
1,2-tetrafluoroethanedisulfonimide,
LiN(CF.sub.3SO.sub.2)(C.sub.4F.sub.9SO.sub.2),
LiC(CF.sub.3SO.sub.2).sub.3, LiPF.sub.4(CF.sub.3).sub.2,
LiPF.sub.4(C.sub.2F.sub.5).sub.2,
LiPF.sub.4(CF.sub.3SO.sub.2).sub.2,
LiPF.sub.4(C.sub.2F.sub.5SO.sub.2).sub.2,
LiBF.sub.2(CF.sub.3).sub.2, LiBF.sub.2(C.sub.2F.sub.5).sub.2,
LiBF.sub.2(CF.sub.3SO.sub.2).sub.2,
LiBF.sub.2(C.sub.2F.sub.5SO.sub.2).sub.2, etc.; and dicarboxylic
acid complex-containing lithium salts, such as lithium
bis(oxalate)borate, lithium difluoro(oxalate)borate, lithium
tris(oxalate)phosphate, lithium difluorobis(oxalate)phosphate,
lithium tetrafluoro(oxalate)phosphate, etc. In some embodiments,
the electrolyte includes LiPF.sub.6 and LiBF.sub.4. In some
embodiments, the electrolyte includes a combination of an inorganic
lithium salt such as LiPF.sub.6, LiBF.sub.4 or the like and a
fluorine-containing organic lithium salt such as
LiCF.sub.3SO.sub.3, LiN(CF.sub.3SO.sub.2).sub.2,
LiN(C.sub.2F.sub.5SO.sub.2).sub.2 or the like.
[0100] In some embodiments, the concentration of the electrolyte is
in the range of about 0.8-about 3 mol/L, such as in the range of
about 0.8-about 2.5 mol/L, in the range of about 0.8-about 2 mol/L
or in the range of about 1-about 2 mol/L, and for example, about 1
mol/L, about 1.15 mol/L, about 1.2 mol/L, about 1.5 mol/L, about 2
mol/L or about 2.5 mol/L.
[0101] 3. Cathode
[0102] The cathode of this application includes a cathode current
collector and a cathode active material layer disposed on one or
two surfaces of the cathode current collector.
[0103] The cathode current collector includes a cathode conductive
material. In some embodiments, the cathode current collector
includes, but is not limited to, aluminum, nickel and stainless
steel.
[0104] The cathode active material layer contains a cathode active
material and a cathode adhesive. The cathode active material layer
may be one or more layers. Each of the plurality of the cathode
active material layers may include the same or different cathode
active materials. The cathode active material is any material
capable of deintercalating metal ions such as lithium ions.
[0105] In some embodiments, the cathode active material is a
lithium-containing compound that provides a high energy density to
an electrochemical device. In some embodiments, the
lithium-containing compound includes one or more of a lithium
transition metal composite oxide and a lithium transition metal
phosphate compound. In some embodiments, the lithium transition
metal composite oxide includes lithium and an oxide having one or
more transition metal elements. In some embodiments, the lithium
transition metal phosphate compound is a phosphate compound
including lithium and having one or more transition metal elements.
In some embodiments, the transition metal element includes one or
more of Co, Ni, Mn and Fe that can result in a higher voltage for
the electrochemical device. In some embodiments, the
lithium-containing compound has the chemical formula
Li.sub.xM.sub.1O.sub.2 or Li.sub.yM.sub.2PO.sub.4, where M.sub.1
and M.sub.2 represent one or more transition metal elements, and
values of x and y vary with charge/discharge state, and are
generally within the following ranges: 0.05.ltoreq.x.ltoreq.1.10
and 0.05.ltoreq.y.ltoreq.1.10.
[0106] In some embodiments, the lithium transition metal composite
oxide includes, but is not limited to, LiCoO.sub.2, LiNiO.sub.2,
and a lithium nickel based transition metal composite oxide
represented by the formula LiNi.sub.1-zM.sub.zO.sub.2, where M is
selected from one or more of Co, Mn, Fe, Al, V, Sn, Mg, Ti, Sr, Ca,
Zr, Mo, Tc, Ru, Ta, W, Re, Yb, Cu, Zn, Ba, B, Cr, Si, Ga, P, Sb and
Nb, and z satisfies the range of 0.005<z<0.5.
[0107] In some embodiments, the lithium transition metal phosphate
compound includes, but is not limited to, LiFePO.sub.4 and a
compound represented by the formula LiFe.sub.1-uMn.sub.uPO.sub.4,
where u<1. By using these compounds as active materials of the
cathode, the obtained electrochemical device has high battery
capacity and excellent cycle performance.
[0108] In some embodiments, the cathode active material further
includes one or more of an oxide, a disulfide, a chalcogenide and a
conductive polymer. In some embodiments, the oxide includes, but is
not limited to, titanium dioxide, vanadium oxide and manganese
dioxide. In some embodiments, the disulfide includes, but is not
limited to, titanium disulfide and molybdenum disulfide. In some
embodiments, the chalcogenide includes, but is not limited to,
niobium selenide. In some embodiments, the conductive polymer
includes, but is not limited to, sulfur, polyaniline and
polythiophene.
[0109] In some embodiments, the cathode adhesive includes, but is
not limited to, one or more of synthetic rubber and polymeric
materials. In some embodiments, the synthetic rubber includes, but
is not limited to, styrene-butadiene rubber, fluororubber, and
ethylene propylene diene. In some embodiments, the polymeric
material includes, but is not limited to, polyvinylidene fluoride
and polyimide.
[0110] In some embodiments, the cathode active material layer
further includes other materials, for example, a cathode conductive
agent. In some embodiments, the cathode conductive agent includes
one or more of a conductive metal material and a conductive
polymer. In some embodiments, the cathode conductive agent includes
one or more of a carbon material or the like. In some embodiments,
the carbon material includes, but is not limited to, graphite,
carbon black, acetylene black and Ketjen black.
[0111] 3. Separator
[0112] In some embodiments, a separator is provided between the
cathode and the anode of the electrochemical device of this
application to prevent current short circuit caused by contact of
the two electrode sheets while allowing lithium ions to pass.
[0113] The material and shape of the separator used in the
electrochemical device of this application are not particularly
limited, and may be any of the techniques disclosed in the prior
art. In some embodiments, the separator includes a polymer (e.g., a
synthetic resin) or an inorganic material (e.g., ceramic) or the
like formed of a material that is stable to the electrolytic
solution of this application. In some embodiments, the separator
includes a porous film made of the polymer or the inorganic
material. In some embodiments, the separator includes a laminate
film that laminates two or more porous films. In some embodiments,
the polymer includes, but is not limited to,
polytetrafluoroethylene, polypropylene and polyethylene.
[0114] In some embodiments, the separator includes the above porous
film (base material layer) and a high-molecular compound layer
disposed on one or two surfaces of the base material layer, which
can improve the adhesion of the separator to the cathode and the
anode and suppress the deflection when the electrode sheet is
wound, thereby suppressing the decomposition reaction of the
electrolytic solution and suppressing the liquid leakage of the
electrolytic solution impregnated into the base material layer. By
using such a separator, the electrical resistance of the
electrochemical device is not significantly increased even in the
case of repeated charging/discharging, thereby suppressing the
expansion of the electrochemical device.
[0115] In some embodiments, the high-molecular compound layer
includes, but is not limited to, polyvinylidene fluoride. The
polyvinylidene fluoride has excellent physical strength and
electrochemical stability. The high-molecular compound layer can be
formed by the following method: after a solution in which the
high-molecular material is dissolved is prepared, a base material
layer is coated with the solution or immersed in the solution, and
finally drying is performed.
[0116] III. Application
[0117] The electrochemical device of this application includes any
device that generates an electrochemical reaction, and its specific
examples include all kinds of primary batteries, secondary
batteries, fuel cells, solar cells or capacitors. In particular,
the electrochemical device is a lithium secondary battery,
including a lithium metal secondary battery, a lithium-ion
secondary battery, a lithium polymer secondary battery or a lithium
ion polymer secondary battery.
[0118] The use of the electrochemical device of this application is
not particularly limited and can be used for any use known in the
prior art. In one embodiment, the electrochemical device of this
application can be used for, but not limited to, notebook
computers, pen input computers, mobile computers, e-book players,
portable telephones, portable fax machines, portable copy machines,
portable printers, headset stereo headphones, VCRs, LCD TVs,
portable cleaners, portable CD players, mini disc players,
transceivers, electronic notebooks, calculators, memory cards,
portable recorders, radios, backup power devices, motors, cars,
motorcycles, power bicycles, bicycles, lighting fixtures, toys,
game consoles, clocks, power tools, flashlights, cameras, large
household batteries, lithium ion capacitors, and the like.
EXAMPLES
[0119] The following describes examples of the lithium ion battery
according to this application and comparative examples for
performance evaluation.
[0120] 1. Preparation of Lithium-Ion Battery
[0121] (1) Preparation of Anode
[0122] The anode active material, the styrene-butadiene rubber, and
the adhesive were mixed in a mass ratio of 96:2:2 with deionized
water, and stirred uniformly to obtain an anode slurry. 12 .mu.m
copper foil was coated with the anode slurry, dried, cold-pressed,
and then subjected to slice cutting and tab welding to obtain an
anode.
[0123] (2) Preparation of Cathode
[0124] Lithium cobalt oxide (LiCoO.sub.2), conductive carbon
(Super-P) and polyvinylidene fluoride (PVDF) were mixed in a mass
ratio of 95:2:3 with N-methylpyrrolidone (NMP), and stirred
uniformly to obtain a cathode slurry. 12 .mu.m aluminum foil was
coated with the cathode slurry, dried, cold-pressed, and then
subjected to slice cutting and tab welding to obtain a cathode.
[0125] (3) Preparation of Electrolytic Solution
[0126] Under a dry argon atmosphere, EC, PC and DEC (weight ratio
is 1:1:1) were mixed, and LiPF.sub.6 was added and mixed uniformly
to form a base electrolytic solution, where the concentration of
LiPF.sub.6 was 1.15 mol/L. Different amounts of propionate and/or
additive were added to the base electrolytic solution to obtain
electrolytic solutions of different examples/comparative
examples.
[0127] (4) Preparation of Separator
[0128] A polyethylene (PE) porous polymer film was used as a
separator.
[0129] (5) Preparation of Lithium-Ion Battery
[0130] The obtained cathode, anode and separator were wound in
order, and placed in outer packaging foil, leaving a liquid
injection port. The lithium-ion battery was obtained by injecting
the electrolytic solution from the liquid injection port,
performing encapsulation, and then performing processes such as
formation and capacity.
[0131] 2. Test Methods
[0132] (1) Test Method for Capacity Retention Rate after Cycle of
Lithium-Ion Battery
[0133] At 45.degree. C., the lithium-ion battery was charged at a
constant current of 1 C to 4.45 V, then charged at a constant
voltage to a current of 0.05 C, and discharged at a constant
current of 1 C to 3.0 V, which was the first cycle. The lithium-ion
battery was cycled several times in accordance with the above
conditions. The capacity retention rate after cycle of the
lithium-ion battery was calculated by the following formula:
Capacity retention rate after cycle=(discharge capacity of the
corresponding number of cycles/discharge capacity of the first
cycle).times.100%
[0134] "1 C" is the current value that completely discharges the
battery capacity within 1 hour.
[0135] (2) Test Method for Storage Capacity Retention Rate after
Cycle of Lithium-Ion Battery
[0136] After 300 cycles according to Test Method (1), the
lithium-ion battery was allowed to stand at 25.degree. C. for 30
minutes, then charged at a constant current of 0.5 C to 4.45 V,
charged at a constant voltage of 4.45 V to 0.05 C, and allowed to
stand for 5 minutes. After storage at 60.degree. C. for 7 days, the
battery was charged at a constant current of 1 C to 4.45 V, then
charged at a constant voltage to a current of 0.05 C, and
discharged at a constant current of 1 C to 3.0 V, and the discharge
capacity was recorded as a storage discharge capacity after cycle.
The storage capacity retention rate after cycle of the lithium-ion
battery was calculated by the following formula:
Storage capacity retention after cycle=(storage discharge capacity
after cycle/discharge capacity of first cycle).times.100%.
[0137] (3) Test Method for High-Temperature Storage Performance of
Lithium-Ion Battery
[0138] At 25.degree. C., the lithium-ion battery was allowed to
stand for 30 minutes, then charged at a constant current of 0.5 C
to 4.45 V, charged at a constant voltage of 4.45 V to 0.05 C, and
allowed to stand for 5 minutes, and the thickness was measured.
Then, after storage at 60.degree. C. for 21 days, the thickness of
the battery was measured. The thickness expansion ratio of the
lithium-ion battery was calculated by the following formula:
Thickness expansion ratio=[(thickness after storage-thickness
before storage)/thickness before storage].times.100%.
[0139] (4) Test Method for Low-Temperature Discharge Performance of
Lithium-Ion Battery
[0140] At 25.degree. C., the battery was charged at a constant
current of 0.5 C to 4.45 V, charged at a constant voltage to 0.05
C, and then discharged at a constant current of 0.5 C to 3.0 V, and
a 25.degree. C. discharge capacity was recorded. At 25.degree. C.,
the battery was charged at a constant current of 0.5 C to 4.45 V,
and charged at a constant voltage to 0.05 C. After that, the
battery was placed in a -20.degree. C. incubator, allowed to stand
for 2 hours, and then discharged at a constant current of 0.5 C to
3.0 V, and a -20.degree. C. discharge capacity was recorded. The
discharge percentage of the lithium-ion battery was calculated by
the following formula:
Discharge percentage=[-20.degree. C. discharge capacity/25.degree.
C. discharge capacity].times.100%.
[0141] 3. Test Results
[0142] Tables 1-4 show the composition and performance of the
lithium-ion batteries of the examples and the lithium-ion batteries
of the comparative examples of this application. The results show
that a lithium-ion battery made of an anode including a carbon
material (for example, artificial graphite) and hydroxyalkyl
methylcellulose (for example, hydroxypropyl methylcellulose sodium)
and an electrolytic solution including PP has excellent capacity
retention rate after cycle, storage capacity retention rate after
cycle, high-temperature storage performance and low-temperature
discharge performance.
[0143] Table 1 shows the effect of the composition of the anode and
electrolytic solution on the performance of the lithium-ion
battery.
[0144] In the case where the anode includes a carbon material (for
example, artificial graphite), the performance of the lithium-ion
battery is directly related to the specific surface area of the
carbon material, the adhesive of the anode and the composition of
the electrolytic solution.
[0145] In the case where the anode includes a carbon material (for
example, artificial graphite) and hydroxyalkyl methylcellulose (for
example, hydroxypropyl methylcellulose sodium), a lithium-ion
battery containing PP (for example, S1) in the electrolytic
solution has an increased capacity retention rate after cycle, an
increased storage capacity retention rate after cycle, a decreased
thickness expansion ratio, and an increased discharge percentage
than a lithium-ion battery that does not contain PP (for example,
D1), which indicates that the lithium-ion battery has improved
cycle performance, high-temperature storage performance and
low-temperature discharge performance. This is because hydroxyalkyl
methylcellulose and PP form a stable protective film on the surface
of the anode, so that lithium ions are easily deintercalated, and
the reversibility of the electrode reaction is improved.
[0146] In the case where the anode includes a carbon material (for
example, artificial graphite) and the electrolytic solution
includes PP, compared with carboxyalkyl cellulose (for example, D2)
and hydroxyalkyl cellulose (for example, D2-D5), the use of
hydroxyalkyl methylcellulose (for example, S7, S21 and S22) as an
adhesive for the anode can significantly increase the capacity
retention rate after cycle and storage capacity retention rate
after cycle of the lithium-ion battery, lower the thickness
expansion ratio and increase the discharge percentage, thereby
improving the cycle performance, high-temperature storage
performance and low-temperature discharge performance of the
lithium-ion battery.
[0147] In the case where the anode includes a carbon material (for
example, artificial graphite) and hydroxyalkyl methylcellulose (for
example, hydroxypropyl methylcellulose sodium) and the electrolytic
solution includes PP, when the specific surface area of the carbon
material is less than or equal to 3 m.sup.2/g, the capacity
retention rate after cycle and the storage capacity retention rate
after cycle of the lithium-ion battery are further increased. This
is because the protective film formed from the hydroxyalkyl
methylcellulose and the propionate on the surface of the anode is
more uniform and stable under a particular specific surface area of
the carbon material, so that it is not easily decomposed during the
cycle. After FEC is added to the electrolytic solution, a composite
protective film can be formed on the surface of the anode, which is
more excellent in stability and low-temperature performance, so
that the performance of the lithium-ion battery can be further
improved.
TABLE-US-00001 TABLE 1 Anode Anode Active Material Storage Specific
Electrolytic solution Capacity Capacity Surface Additive Retention
Retention Thickness Discharge Area Solvent Content Rate After Rate
After Expansion Percentage Type (m.sup.2/g) Adhesive (30 wt %) Type
(wt %) Cycle (%) Cycle (%) Ratio (%) (%) Example S1 Artificial 1.6
Hydroxypropyl PP -- -- 33 35 17.6 35.2 S2 graphite methylcellulose
sodium PP FEC 0.01 62 61 7.8 40.9 S3 0.1 65 63 6.5 42.8 S4 0.5 70
65 5.8 43.4 S5 1 75 72 5.4 43.5 S6 2 77 78 5.3 45.1 S7 5 82 85 5.2
47.2 S8 10 74 76 5.9 47.6 S9 Artificial 1.6 Hydroxypropyl PP Cis
DFEC 5 77 75 5.6 43.5 S10 graphite methylcellulose sodium Trans 71
70 5.3 44.3 DFEC S11 TFEMC 72 73 5.7 48.3 S12 ETFEC 73 75 5.8 42.2
S13 1.8 PP -- -- 52 59 8.3 46.3 S14 Artificial Hydroxypropyl FEC 5
81 84 5.4 50.4 graphite methylcellulose sodium S15 Artificial 2
Hydroxypropyl PP -- -- 50 53 8.7 51.7 S16 graphite methylcellulose
sodium FEC 5 77 73 6.3 55 S17 Artificial 3 Hydroxypropyl PP -- --
46 47 8.9 52.3 S18 graphite methylcellulose sodium FEC 5 63 65 6.5
57.3 S19 Artificial 3.5 Hydroxypropyl PP -- -- 43 42 9.1 53.9 S20
graphite methylcellulose sodium FEC 5 61 58 6.8 58.7 S21 Artificial
1.6 Hydroxyethyl PP FEC 5 81 83 5.7 41.8 graphite methylcellulose
sodium S22 1.6 Hydroxymethyl 79 81 5.9 42.7 methylcellulose sodium
S23 1.6 Hydroxypropyl 84 87 5.2 49.1 methylcellulose lithium S24
1.6 Hydroxyethyl 81 80 5.4 44.2 methylcellulose lithium S25 1.6
Hydroxymethyl 79 78 5.3 46.9 methylcellulose lithium S26 Artificial
2 Hydroxypropyl 70 69 8.1 40.1 graphite:silica = methylcellulose
sodium 95:5 (weight ratio) S27 Artificial 2 Hydroxypropyl 68 66 8.9
38.8 graphite:silica = methylcellulose sodium 95:5 (weight ratio)
Comparative example D1 Artificial 1.6 Hydroxypropyl -- -- -- 31 32
22.1 12.5 graphite methylcellulose sodium D2 Artificial 1.6
Carboxymethylcellulose PP FEC 5 42 45 5.7 41 graphite sodium D3 1.6
Hydroxymethyl 43 44 5.9 43.2 cellulose sodium D4 1.6 Hydroxyethyl
cellulose 41 40 6.1 43.4 sodium D5 1.6 Hydroxypropyl cellulose 40
42 6.4 39.5 sodium D6 Artificial 2 Carboxymethylcellulose 41 42
12.7 33.6 graphite:silica = sodium 95:5 (weight ratio) D7
Artificial 1.6 Carboxymethylcellulose -- -- -- 28 29 12.3 8.5
graphite sodium D8 Artificial 1.6 Carboxymethylcellulose PP -- --
29 30 23.5 30.6 graphite sodium D9 Artificial 1.8
Carboxymethylcellulose PP FEC 5 44 47 5.8 45.3 graphite sodium
[0148] Table 2 shows the effect of the solvent composition in the
electrolytic solution on the performance of a lithium-ion
battery.
[0149] It can be seen from S28-S33 that even if the content of PP
in the electrolytic solution changes to some extent, the
lithium-ion battery can still obtain good capacity retention rate
after cycle, storage capacity retention rate after cycle,
high-temperature storage performance and low-temperature discharge
performance, and particularly the improvement of the
low-temperature discharge performance of the lithium-ion battery is
especially remarkable. When the content of PP in the electrolytic
solution is in the range of about 10 wt %-50 wt %, the performance
of the lithium-ion battery is particularly excellent. This is
because within this content range, the protective film formed by
hydroxyalkyl methylcellulose and PP is more stable, the film
impedance is lower, and the passage of lithium ions is facilitated,
thereby improving the dynamic performance of the lithium-ion is
battery.
[0150] When the electrolytic solution includes the additive FEC,
during the charging/discharging process of the lithium-ion battery,
FEC and PP act together on the surface of the anode to form a
stable protective film, thereby suppressing the decomposition
reaction of the electrolytic solution, which contributes to the
increase of the capacity retention rate after cycle and storage
capacity retention rate after cycle of the lithium-ion battery. The
content of FEC in the electrolytic solution is not particularly
limited, and is, in some embodiments, 0.01 wt %-15 wt %. When the
content of PP in the electrolytic solution is 3-10 times that of
FEC, the performance of the lithium-ion battery is more
excellent.
[0151] In addition, an additional solvent (for example, EP or GBL)
may be included in the electrolytic solution to help improve the
capacity retention rate after cycle, storage capacity retention
rate after cycle and low-temperature discharge performance of the
lithium-ion battery.
TABLE-US-00002 TABLE 2 Anode Anode Active Electrolytic solution
Storage Material Capacity Capacity Specific Solvent Additive
Retention Retention Thickness Discharge Surface PP Other Content
Rate After Rate After Expansion Percentage Example Type Area
(m.sup.2/g) Adhesive (wt %) (wt %) Type (wt %) Cycle (%) Cycle (%)
Ratio (%) (%) S28 Artificial 1.6 Hydroxypropyl 10 -- FEC 5 73 76
4.8 22.3 S29 graphite methylcellulose sodium 15 75 77 4.9 35.3 S30
20 77 79 5 36.5 S31 30 82 85 5.2 47.2 S32 40 85 86 5.9 52.9 S33 50
83 81 6.3 59.4 S34 Artificial 1.6 Hydroxypropyl 30 10 vol % FEC 5
91 90 5 53.2 graphite methylcellulose lithium EP S35 Hydroxyethyl
85 81 5.1 51.1 methylcellulose lithium S36 Hydroxypropyl 20 vol %
83 84 5.8 58.8 methylcellulose sodium EP S37 5 vol % 85 93 5.7 56.4
GBL
[0152] Table 3 shows the effects of the solute composition in the
electrolytic solution on the performance of a lithium-ion
battery.
[0153] In Examples S38-S55, in addition to LiPF.sub.6, the
electrolytic solution further includes other lithium salts as
electrolytes, for example, LiBF.sub.4, LiPO.sub.2F.sub.2 and LiFSI.
The results show that the addition of additional electrolyte to the
electrolytic solution can improve the capacity retention rate after
cycle, storage capacity retention rate after cycle,
high-temperature storage performance and low-temperature discharge
performance of the lithium-ion battery. The content of the other
lithium salts in the electrolytic solution is not particularly
limited. In some embodiments, the content of other lithium salts is
in the range of 0.01 wt %-0.1 wt % based on the total weight of the
electrolytic solution. Within this range, other lithium salts can
act synergistically with PP and hydroxyalkyl methylcellulose to
form a strong composite protective film, thereby stabilizing the
interface and is suppressing the reaction between the electrolytic
solution and the cathode/anode active material.
TABLE-US-00003 TABLE 3 Anode Electrolytic solution Anode Active
Material Other lithium salts Specific other than LiPF.sub.6 Surface
Area Content Example Type (m.sup.2/g) Adhesive Solvent Type (wt %)
S7 Artificial 1.6 Hydroxypropyl 30 wt % PP -- -- graphite
methylcellulose sodium S38 Artificial 1.6 Hydroxypropyl 30 wt % PP
LiBF.sub.4 0.01 S39 graphite methylcellulose 0.05 S40 sodium 0.1
S41 LiPO.sub.2F.sub.2 0.01 S42 0.05 S43 0.1 S44 LiFSI 0.01 S45 0.05
S46 0.1 S47 30 wt % PP + LiBF.sub.4 0.01 S48 20 wt % EP 0.05 S49
0.1 S50 Artificial 1.6 Hydroxypropyl 30 wt % PP + LiBF.sub.4 0.01
S51 graphite methylcellulose 20 wt % EP 0.05 S52 lithium 0.1 S53
Artificial 2 LiBF.sub.4 0.01 S54 graphite:silica = 0.05 S55 95:5
0.1 (weight ratio) Storage Electrolytic solution Capacity Capacity
Thickness Additive Retention Retention Expansion Discharge Content
Rate After Rate After Ratio Percentage Example Type (wt %) Cycle
(%) Cycle (%) (%) (%) S7 FEC 5 82 85 5.2 47.2 S38 FEC 5 83 86 5.3
48.4 S39 85 87 5.2 51.1 S40 86 88 5.1 55.6 S41 FEC 5 86 88 5.2 47.1
S42 88 87 5.1 46.6 S43 87 86 4.9 44.7 S44 FEC 5 83 82 5.3 49.9 S45
84 85 5.2 50.7 S46 86 87 5.1 51.2 S47 FEC 5 84 83 5.6 51.5 S48 87
84 5.5 54.1 S49 88 85 5.4 58.9 S50 FEC 5 86 85 5.6 54.7 S51 90 88
5.5 57.3 S52 91 80 5.4 62.1 S53 FEC 5 61 70 7.9 51.3 S54 63 71 7.5
52.2 S55 64 73 7.4 52.6
[0154] Table 4 shows the effect of the composition of the additive
in the electrolytic solution on the performance of a lithium-ion
battery.
[0155] As shown in Examples S56-S118, one or more of the following
additives may be included in the electrolytic solution: FEC, PS,
DTD, VC, SN, ADN, EDN, HTCN, TCEP, T3P, SCAH and PSAH. The obtained
lithium-ion battery has good capacity retention rate after cycle,
storage capacity retention rate after cycle, high-temperature
storage performance and low-temperature discharge performance.
[0156] When the electrolytic solution includes two or more kinds of
additives, the capacity retention rate after cycle and the storage
capacity retention rate after cycle of the lithium-ion battery are
further improved.
TABLE-US-00004 TABLE 4 Anode Anode Active Material Electrolytic
solution Specific Other lithium Surface salts Additive Area Solvent
Content Additive Content Example Type (m.sup.2/g) Adhesive (wt %)
Type (wt %) 1 (wt %) S1 Artificial 1.6 Hydroxypropyl 30 wt % PP --
-- -- -- graphite methylcellulose sodium S7 Artificial 1.6
Hydroxypropyl 30 wt % PP -- -- FEC 5 graphite methylcellulose
sodium S56 Artificial 1.6 Hydroxypropyl 30 wt % PP -- -- -- --
graphite methylcellulose lithium S57 Artificial 1.6 Hydroxypropyl
30 wt % PP -- -- FEC 5 S58 graphite methylcellulose sodium
LiBF.sub.4 0.1 S59 LiPO.sub.2F.sub.2 0.1 S60 -- -- S61 LiBF.sub.4
0.1 S62 LiPO.sub.2F.sub.2 0.1 S63 -- -- S64 LiBF.sub.4 0.1 S65
LiPO.sub.2F.sub.2 0.1 S66 -- -- S67 LiBF.sub.4 0.1 S68
LiPO.sub.2F.sub.2 0.1 S69 -- -- S70 LiBF.sub.4 0.1 S71
LiPO.sub.2F.sub.2 0.1 S72 -- -- S73 LiBF.sub.4 0.1 S74
LiPO.sub.2F.sub.2 0.1 S75 -- -- S76 LiBF.sub.4 0.1 S77
LiPO.sub.2F.sub.2 0.1 S78 -- -- S79 LiBF.sub.4 0.1 S80
LiPO.sub.2F.sub.2 0.1 S81 Artificial 1.6 Hydroxypropyl 30 wt % PP
-- -- FEC 5 S82 graphite methylcellulose lithium S83 S84 S85 S86
S87 S88 S89 Artificial 1.6 Hydroxypropyl 30 wt % PP + -- -- FEC 5
S90 graphite methylcellulose lithium 20 wt % EP S91 S92 S93 S94 S95
S96 S97 Artificial 1.6 Hydroxypropyl 30 wt % PP -- -- FEC 5 S98
graphite methylcellulose lithium S99 S100 S101 S102 S103 S104
Artificial 1.6 Hydroxypropyl 30 wt % PP -- -- FEC 5 S105 graphite
methylcellulose sodium S106 S107 30 wt % PP + -- -- FEC 5 S108 20
wt % EP S109 S110 Artificial 1.6 Hydroxypropyl 30 wt % PP -- -- FEC
5 S111 graphite methylcellulose lithium S112 S113 30 wt % PP + --
-- FEC 5 S114 20 wt % EP S115 S116 Artificial 1.6 Hydroxypropyl 30
wt % PP -- -- FEC 5 graphite methylcellulose lithium S117
Artificial 1.6 Hydroxypropyl 30 wt % PP -- -- FEC 5 graphite
methylcellulose lithium S118 Artificial 1.6 Hydroxypropyl 30 wt %
PP -- -- -- -- graphite methylcellulose lithium Storage Capacity
Capacity Retention Retention Electrolytic solution Rate Rate
Additive After After Thickness Discharge Additive Content Additive
Content Cycle Cycle Expansion Percentage Example 2 (wt %) 3 (wt %)
(%) (%) Ratio (%) (%) S1 -- -- -- -- 33 35 17.6 35.2 S7 -- -- -- --
82 85 5.2 47.2 S56 PS 2 -- -- 73 74 7.2 15.1 S57 PS 2 -- -- 87 86
5.5 48.1 S58 88 89 5.3 49.5 S59 86 87 5.1 50.3 S60 DTD 2 -- -- 89
90 5.8 49.3 S61 90 91 5.4 50.7 S62 91 90 5.2 51.5 S63 VC 0.5 -- --
88 89 5.3 47 S64 86 85 5.1 46.4 S65 87 88 4.9 45.2 S66 SN 4 -- --
89 90 4.8 39.7 S67 90 91 4.3 41.1 S68 91 92 5 41.9 S69 ADN 5 -- --
89 90 5.2 38.3 S70 88 89 5.1 39.7 S71 90 91 5.6 40.5 S72 EDN 1 --
-- 88 87 5.3 42.5 S73 88 89 5.8 43.9 S74 90 91 5.5 44.7 S75 HTCN 2
-- -- 89 90 5.9 38.5 S76 90 91 5.5 39.9 S77 91 92 5.9 40.8 S78 TCEP
2 -- -- 92 90 5.2 42.9 S79 93 92 5.8 43.6 S80 89 90 5.9 44.5 S81 PS
2 -- -- 90 89 5.6 53.2 S82 DTD 2 -- -- 88 87 5.9 55.9 S83 VC 0.5 --
-- 89 87 5.3 49.8 S84 SN 4 -- -- 86 85 5.5 43.9 S85 ADN 5 -- -- 89
91 5.4 44.1 S86 EDN 1 -- -- 90 91 5.8 48.5 S87 HTCN 2 -- -- 91 92
5.1 42 S88 TCEP 2 -- -- 92 93 5.2 48.8 S89 PS 2 -- -- 90 91 5.7
61.6 S90 DTD 2 -- -- 91 90 6 64.3 S91 VC 0.5 -- -- 92 89 5.4 58.2
S92 SN 4 -- -- 89 90 5.6 52.3 S93 ADN 5 -- -- 90 90 5.5 52.5 S94
EDN 1 -- -- 91 90 5.9 56.9 S95 HTCN 2 -- -- 92 90 5.2 50.4 S96 TCEP
2 -- -- 93 94 5.3 57.2 S97 VC 0.5 PS 3 92 93 5 53.2 S98 PS 3 ADN 3
93 94 5.3 53.9 S99 PS 3 EDN 2 94 93 5.1 49.6 S100 PS 3 HTCN 1 93 95
5.4 43.9 S101 SN 5 HTCN 2 94 94 5.3 45.7 S102 PS 3 TCEP 2 95 94 5.1
48.5 S103 DTD 0.5 TCEP 3 94 95 4.8 42.3 S104 -- -- T3P 0.5 87 85
4.9 53.5 S105 SCAH 0.5 86 83 5.1 52.1 S106 PSAH 0.5 82 83 5 49.6
S107 -- -- T3P 0.5 88 86 5.3 63.6 S108 SCAH 0.5 85 84 5.9 61.8 S109
PSAH 0.5 83 82 5.7 59.5 S110 -- -- T3P 0.5 89 90 5.1 58.3 S111 SCAH
0.5 86 84 5.2 56.2 S112 PSAH 0.5 85 83 5.2 55.9 S113 -- -- T3P 0.5
86 84 5.5 67.3 S114 SCAH 0.5 84 85 6.1 62.8 S115 PSAH 0.5 83 86 5.9
61.3 S116 DTD 2 T3P 0.5 90 92 4.7 57.5 S117 PS 2 T3P 0.5 89 90 4.8
56 S118 PS 2 T3P 0.5 87 89 4.9 52.5
[0157] Although this application has been described with reference
to the implementations and the embodiments, this application is not
limited to the examples described in the implementations and the
embodiments, and various changes can be made. For example, as a
kind of secondary battery, a lithium-ion secondary battery has been
described. However, the applicable secondary battery type is not
limited to this. The secondary battery of this application can be
similarly applied to a secondary battery in which the capacity of
the anode includes a capacity due to deintercalation of lithium
ions and a capacity associated with precipitation and dissolution
of lithium metal, and the battery capacity is represented by the
sum of these capacities. In this case, an anode material capable of
deintercalating lithium ions is used as the anode active material,
and the chargeable capacity of the anode material is set to a value
smaller than the discharge capacity of the cathode.
[0158] Further, this application is applicable to a cylindrical
type, a laminated is film type, and a battery device having a
spirally wound structure. However, the applicable structure is not
limited thereto. The secondary battery of this application can be
similarly applied to a battery having other battery structures such
as a square battery, a coin battery and a button battery, or a
battery in which the battery device has other structures such as a
laminated structure.
[0159] Further, the case of using lithium as an electrode reactant
has been described. However, the electrode reactant is not
necessarily limited to this. As the electrode reactant, for
example, other Group 1 elements such as Na and K, Group 2 elements
such as Mg and Ca, or other light metals such as Al may be used.
The effect of this application can be obtained irrespective of the
type of the electrode reactant, whereby a similar effect can be
obtained even if the type of the electrode reactant is changed.
[0160] Further, regarding the values of the above respective
components, the appropriate ranges derived from the results of the
embodiments are explained. However, the description does not
completely exclude the possibility that the content/value is
outside the above range. That is, the above-described appropriate
range/value is a particularly preferable range/value for obtaining
the effect of the present application. Therefore, as long as the
effect of the present application is obtained, the content may be
outside the above range/value to some extent.
[0161] References to "some embodiments", "part of embodiments",
"one embodiment", "another example", "example", "specific example"
or "part of examples" in the whole specification mean that at least
one embodiment or example in this application comprises specific
features, structures, materials or characteristics described in the
embodiments or examples. Thus, the descriptions appear throughout
the specification, such as "in some embodiments", "in an
embodiment", "in one embodiment", "in another example", "in one
example", "in a specific example" or "an example", which does not
necessarily refer to the same embodiment or example in this
application. Furthermore, the specific features, structures,
materials or is characteristics in the descriptions can be combined
in any suitable manner in one or more embodiments or examples.
[0162] Although the illustrative embodiments have been shown and
described, it should be understood by those skilled in the art that
the above embodiments cannot be interpreted as limiting this
application, and the embodiments can be changed, substituted and
modified without departing from the spirit, principle and scope of
this application.
ABBREVIATION
TABLE-US-00005 [0163] Abbr Material Name Abbr Material Name EC
Ethylene carbonate PS 1,3-propane sultone PC Propylene carbonate
DTD Ethylene sulfate GBL .gamma.-butyrolactone SN Succinonitrile EP
Ethyl propionate ADN Adiponitrile PP Propyl propionate HTCN
1,3,6-hexane trinitrile VC Vinylene carbonate EDN Ethylene glycol
bis(2- cyanoethyl)ether FEC Fluoroethylene carbonate TCEP
1,2,3-tris(2- cyanoethoxy)propane LiBF.sub.4 Lithium
tetrafluoroborate T3P 1-propylphosphoric acid cyclic anhydride
LiPO.sub.2F.sub.2 Lithium difluorophosphate SCAH Succinic anhydride
LiPF.sub.6 Lithium PSAH Sulfopropionic hexafluorophosphate
anhydride LiFSI Lithium TFEMC Methyl trifluoroethyl
trifluoromethane- carbonate sulfonylimide Cis Cis
4,4-difluoroethylene ETFEC Ethyl trifluoroethyl DFEC carbonate
carbonate Trans Trans 4,4-difluoroethylene DFEC carbonate
* * * * *