U.S. patent application number 14/627687 was filed with the patent office on 2015-08-27 for cross-linked binder composition for lithium ion batteries and methods for producing the same.
The applicant listed for this patent is HERCULES INCORPORATED. Invention is credited to Sung Gun Chu, Alan Edward Goliaszewski, Cristian Grigoras, Shufu Peng.
Application Number | 20150243995 14/627687 |
Document ID | / |
Family ID | 53879020 |
Filed Date | 2015-08-27 |
United States Patent
Application |
20150243995 |
Kind Code |
A1 |
Chu; Sung Gun ; et
al. |
August 27, 2015 |
CROSS-LINKED BINDER COMPOSITION FOR LITHIUM ION BATTERIES AND
METHODS FOR PRODUCING THE SAME
Abstract
The presently disclosed and/or claimed inventive concept(s)
relates to a binder composition comprising a cross-linked polymer
system. The cross-linked polymer system comprises an ionizable
water soluble polymer cross-linked with a component using an
esterification catalyst and/or an epoxy resin with two or more
epoxide groups. The presently disclosed and/or claimed inventive
concept(s) also relates generally to the compositions and methods
of making electrodes, in particular but without limitation, anodes,
with a binder composition comprising an ionizable water soluble
polymer cross-linked with a component.
Inventors: |
Chu; Sung Gun; (Hockessin,
DE) ; Goliaszewski; Alan Edward; (Hockessin, DE)
; Peng; Shufu; (Hockessin, DE) ; Grigoras;
Cristian; (Suffern, NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HERCULES INCORPORATED |
Wilmington |
DE |
US |
|
|
Family ID: |
53879020 |
Appl. No.: |
14/627687 |
Filed: |
February 20, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61943124 |
Feb 21, 2014 |
|
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|
Current U.S.
Class: |
429/217 ;
523/447; 525/54.2; 525/54.23 |
Current CPC
Class: |
C08L 5/04 20130101; C08B
37/0096 20130101; C08L 5/00 20130101; H01M 4/505 20130101; C08L
63/00 20130101; H01M 4/622 20130101; C09J 105/00 20130101; C09J
101/286 20130101; C08L 33/02 20130101; H01M 4/663 20130101; C09J
105/04 20130101; C08L 1/284 20130101; C09J 101/284 20130101; H01M
4/48 20130101; H01M 4/134 20130101; H01M 4/5825 20130101; H01M
4/133 20130101; H01M 4/525 20130101; C08G 59/3218 20130101; H01M
4/661 20130101; H01M 4/669 20130101; H01M 4/587 20130101; H01M
4/386 20130101; H01M 4/13 20130101; C08L 1/286 20130101; Y02E 60/10
20130101; C08G 59/245 20130101; C09J 105/00 20130101; C08L 1/286
20130101; C09J 105/00 20130101; C08L 1/284 20130101; C09J 101/286
20130101; C08L 5/00 20130101; C09J 101/284 20130101; C08L 5/00
20130101; C09J 105/00 20130101; C08L 1/286 20130101; C08L 1/286
20130101; C09J 105/04 20130101; C08L 1/286 20130101; C08L 1/286
20130101; C09J 105/00 20130101; C08L 33/02 20130101 |
International
Class: |
H01M 4/62 20060101
H01M004/62; C08L 1/28 20060101 C08L001/28; C08L 5/00 20060101
C08L005/00; C08L 63/00 20060101 C08L063/00; C08L 5/04 20060101
C08L005/04 |
Claims
1-65. (canceled)
66. A binder composition for a lithium ion battery electrode
comprising a cross-linked polymer system, wherein the cross-linked
polymer system comprises (i) an ionizable water soluble polymer at
least partially cross-linked with a component, and (ii) at least
one of (a) an esterification catalyst and (b) an epoxy resin
comprising at least two epoxide groups, and wherein the
cross-linked polymer system is insoluble in water.
67. The binder composition of claim 66, wherein the ionizable water
soluble polymer comprises at least one of xanthan gum, alginate,
and an anionically modified polysaccharide selected from the group
consisting of carboxyalkyl cellulose, carboxyalkyl hydroxyalkyl
cellulose, and combinations thereof, and wherein the ionizable
water soluble polymer comprises at least one hydroxyl group.
68. The binder composition of claim 67, wherein the ionizable water
soluble polymer comprises at least one of lithiated xanthan gum,
lithiated alginate, and a lithiated anionically modified
polysaccharide selected from the group consisting of lithiated
carboxyalkyl cellulose, lithiated carboxyalkyl hydroxyalkyl
cellulose, and combinations thereof.
69. The binder composition of claim 66, wherein the component is a
synthetic polymer comprising at least one carboxyl group and is
selected from the group consisting of polyacrylic acid, polyacrylic
acid copolymers, methyl vinyl ether and maleic anhydride
copolymers, modified methyl vinyl ether and maleic anhydride
copolymers, styrene maleic anhydride copolymers, and combinations
thereof.
70. The binder composition of claim 66, wherein the component is a
polycarboxylic acid selected from the group consisting of formic
acid, acetic acid chloroacetic acid, dichloroacetic acid,
trichloroacetic acid, trifluoroacetic acid, oxalic acid, benzoic
acid, and combinations thereof.
71. The binder composition of claim 66, wherein the component is
lithiated.
72. The binder composition of claim 66, wherein the esterification
catalyst is selected from the group consisting of sodium
hypophosphite, sulphonic acid, methane sulphonic acid,
trifluoromethane sulphonic acid, titanate esters, dialkyl tin, and
combinations thereof.
73. The binder composition of claim 66, wherein the epoxy resin
comprising at least two epoxide groups is at least one of a
di-epoxy, tri-epoxy, tetra-epoxy, and combinations thereof.
74. The binder composition of claim 73, further comprising an epoxy
cross-linking catalyst selected from the group consisting of
tertiary amines, quaternary amines, imidazoles, phosphonium
compounds, chelates, and combinations thereof.
75. A slurry for use in preparation of a lithium ion battery,
comprising: an electrode active material; an ionizable water
soluble polymer; a component; at least one of an esterification
catalyst and an epoxy resin; and water.
76. The slurry of claim 75, wherein the electrode active material
is at least one of (i) an anode active material and (ii) a cathode
active material.
77. The slurry of claim 76, wherein the anode active material is
selected from the group consisting of artificial graphite, natural
graphite, surface modified graphite, coke, hard carbon, soft
carbon, carbon fiber, conductive carbon, and combinations
thereof.
78. The slurry of claim 77, wherein the anode active material
further comprises at least one of silicon and silicon oxide,
wherein the silicon-containing anode active material comprises at
least one hydroxyl group on the surface.
79. The slurry of claim 75, wherein the ionizable water soluble
polymer comprises at least one of xanthan gum, alginate, and an
anionically modified polysaccharide selected from the group
consisting of carboxyalkyl cellulose, carboxyalkyl hydroxyalkyl
cellulose, and combinations thereof, and wherein the ionizable
water soluble polymer comprises at least one hydroxyl group.
80. The slurry of claim 79, wherein the ionizable water soluble
polymer comprises at least one of lithiated xanthan gum, lithiated
alginate, and a lithiated anionically modified polysaccharide
selected from the group consisting of lithiated carboxyalkyl
cellulose, lithiated carboxyalkyl hydroxyalkyl cellulose, and
combinations thereof.
81. The slurry of claim 75, wherein the component is a synthetic
polymer comprising at least one carboxyl group and is selected from
the group consisting of polyacrylic acid, polyacrylic acid
copolymers, methyl vinyl ether and maleic anhydride copolymers,
modified methyl vinyl ether and maleic anhydride copolymers,
styrene maleic anhydride copolymers, and combinations thereof.
82. The slurry of claim 75, wherein the component is a
polycarboxylic acid selected from the group consisting of formic
acid, acetic acid chloroacetic acid, dichloroacetic acid,
trichloroacetic acid, trifluoroacetic acid, oxalic acid, benzoic
acid, and combinations thereof.
83. The slurry of claim 75, wherein the component is lithiated.
84. The slurry of claim 75, wherein the esterification catalyst is
selected from the group consisting of sodium hypophosphite,
sulphonic acid, methane sulphonic acid, trifluoromethane sulphonic
acid, titanate esters, dialkyl tin, and combinations thereof.
85. The slurry of claim 75, wherein the epoxy resin comprises at
least two epoxide groups.
86. The slurry of claim 85, wherein the epoxy resin is in an
aqueous dispersion comprising at least one surfactant selected from
the group consisting of phosphate esters, imidazolines, amides, and
combinations thereof.
87. The slurry of claim 85, further comprising an epoxy
cross-linking catalyst selected from the group consisting of
tertiary amines, quaternary amines, imidazoles, phosphonium
compounds, chelates, and combinations thereof.
88. A film for use in preparation of a lithium ion battery,
comprising: an electrode active material; and the binder
composition of claim 66.
89. An electrode for a lithium ion battery, comprising: the film of
claim 88; and a current collector.
90. The electrode of claim 89, wherein the current collector is
made of a material selected from the group consisting of aluminum,
carbon, copper, stainless steel, nickel, zinc, silver, and
combinations thereof.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims the benefit under 35 U.S.C.
119 (e) of U.S. Provisional Patent Application Ser. No. 61/943,124,
filed on Feb. 21, 2014, the entire content of which is hereby
expressly incorporated herein by reference.
BACKGROUND
[0002] 1. Field of the Invention
[0003] The presently disclosed and/or claimed inventive concept(s)
relates to a binder composition comprising a cross-linked polymer
system comprising an ionizable water soluble polymer cross-linked
with a component using an esterification catalyst and/or an epoxy
resin with two or more epoxide groups. Additionally, the presently
disclosed and/or claimed inventive concept(s) relates generally to
compositions and methods of making electrodes, in particular but
without limitation, anodes, with a binder composition comprising an
ionizable water soluble polymer cross-linked with a component.
[0004] 2. Background of the Invention
[0005] Lithium batteries are used in many products including
medical devices, electric cars, airplanes, and most notably,
consumer products such as laptop computers, cell phones, and
cameras. Due to their high energy densities, high operating
voltages, and low-self discharges, lithium ion batteries have
overtaken the secondary battery market and continue to find new
uses in products and developing industries.
[0006] Generally, lithium ion batteries (LIBs) comprise an anode, a
cathode, and an electrolyte material such as an organic solvent
containing a lithium salt. More specifically, the anode and cathode
(collectively, "electrodes") are formed by mixing either an anode
active material or a cathode active material with a binder and a
solvent to form a paste or slurry which is then coated and dried on
a current collector, such as aluminum or copper, to form a film on
the current collector. The anodes and cathodes are then layered or
coiled prior to being housed in a pressurized casing containing an
electrolyte material, which all together forms a lithium ion
battery.
[0007] When making electrodes, it is important to select a binder
with sufficient adhesive and chemical properties such that the film
coated on the current collector will maintain contact with the
current collector even when manipulated to fit into the pressurized
battery casing. Since the film contains the electrode active
material, there will likely be significant interference with the
electrochemical properties of the battery if the film does not
maintain sufficient contact with the current collector.
Additionally, it is important to select a binder that is
mechanically compatible with the electrode active material(s) such
that it is capable of withstanding the degree of expansion and
contraction of the electrode active material(s) during charging and
discharging of the battery. As electrode active materials continue
to evolve, binders will need to continue to adapt in order to
remain mechanically compatible with the evolving electrode active
materials. If not, large capacity fades during cycling can result
from the use of new electrode active materials like, for example,
silicon-containing materials with currently existing binder
compositions. As such, binders play an important role in the
performance of lithium ion batteries.
[0008] Currently, lithium ion battery technology generally teaches
binder compositions comprising cellulosic materials selected from
carboxymethylcellulose, carboxyethylcellulose, aminoethylcellulose,
and/or oxyethylcellulose. More specifically, carboxymethylcellulose
(CMC) has become the preferred choice of cellulose material to be
included in LIB binders comprising graphite as the anode active
material. See, for example, US 2004/0258991 filed by Young-Min Choi
et al., hereby incorporated herein by reference in its entirety.
Binder compositions comprising these cellulose derivatives alone
may not have the mechanical properties necessary, however, to
support the large volume changes that occur with some of the
electrode active materials currently of interest.
[0009] Specifically, silicon-containing material has recently come
to the forefront as a promising anode active material for LIBs.
See, for example, B. Lestriez et al., On the Binding Mechanism of
CMC in Si Negative Electrodes for Li-Ion Batteries,
Electrochemistry Communications, vol. 9, 2801-2806 (2007), which is
hereby incorporated herein by reference in its entirety. Some of
the reasons that silicon-containing material has come to the
forefront as a promising anode active material are: its high
theoretical specific capacity of 4200 mAhg.sup.-1 for Li.sub.4.4Si,
low electrochemical potential between 0 and 0.4 V versus
Li/Li.sup.+, and a small initial irreversible capacity compared
with other metal- or alloy-based anode materials. See, B. Koo et
al., A Highly Cross-linked Polymeric Binder for High-Performance
Silicon Negative Electrodes in Lithium Ion Batteries, Angew. Chem.
Int. Ed. 2012, 51, 8762-8767, hereby incorporated herein by
reference in its entirety. It has been found herein that a specific
capacity of about 600 mAhg.sup.-1 can be achieved by mixing
graphite with silicon oxide (SiO.sub.x) and conductive carbon at a
weight ratio of about 0.795/0.163/0.042 and, alternatively, a
specific capacity of about 450 mAhg.sup.-1 can be achieved by
mixing graphite with silicon oxide at a weight ratio of about 92 to
5, both of which increase the specific capacity of the anode
material above the 340 mAhg.sup.-1 associated with graphite
independent of any other electrode active material. Silicon has
been known, however, to undergo large volume changes during
charging and discharging, which can cause problems for a battery's
capacity and overall performance. The presently disclosed and/or
claimed binder compositions comprising guaran and/or modified
guaran, however, actually improve the capacity of lithium ion
batteries comprising a silicon-containing electrode active
material. This is due in part to guaran having a high molecular
weight and strong adhesive properties, which contribute to guaran
being capable of withstanding the large volume changes generally
associated with silicon-containing electrode active materials.
[0010] The presently disclosed and/or claimed inventive concept(s)
is directed to a binder composition comprising a cross-linked
polymer system comprising an ionizable water soluble polymer
cross-linked with a component using an esterification catalyst
and/or an epoxy resin having two or more epoxide groups. A binder
composition comprising such cross-linked polymer system is also
capable of improving the capacity of lithium ion batteries
comprising a silicon-containing electrode active material. This is
due to the binder composition comprising the cross-linked polymer
system being capable of holding the silicon-based electrode active
material in the binder composition while minimizing the effects of
the expansion and contraction of the silicon while charging and
discharging the electrodes, which could otherwise lead to a
mechanical failure of the battery. See Koo et al., A Highly
Cross-linked Polymeric Binder for High-Performance Silicon Negative
Electrodes in Lithium Ion Batteries, Angew. Chem. Int. Ed. 2012,
51, 8762-8767. It has been found, as disclosed and/or claimed
herein, that the use of esterification catalysts and/or an epoxide
resin with two or more epoxide groups enhances the above-described
cross-linking feature, resulting in batteries comprising
silicon-containing electrode active materials with even more
improved mechanical and electrochemical properties.
DETAILED DESCRIPTION OF THE INVENTIVE CONCEPT(S)
[0011] Before explaining at least one embodiment of the presently
disclosed and/or claimed inventive concept(s) in detail, it is to
be understood that the presently disclosed and/or claimed inventive
concept(s) is not limited in its application to the details of
construction and the arrangement of the components or steps or
methodologies set forth in the following description or illustrated
in the drawings. The presently disclosed and/or claimed inventive
concept(s) is capable of other embodiments or of being practiced or
carried out in various ways. Also, it is to be understood that the
phraseology and terminology employed herein is for the purpose of
description and should not be regarded as limiting.
[0012] Unless otherwise defined herein, technical terms used in
connection with the presently disclosed and/or claimed inventive
concept(s) shall have the meanings that are commonly understood by
those of ordinary skill in the art. Further, unless otherwise
required by context, singular terms shall include pluralities and
plural terms shall include the singular.
[0013] All patents, published patent applications, and non-patent
publications mentioned in the specification are indicative of the
level of skill of those skilled in the art to which the presently
disclosed and/or claimed inventive concept(s) pertains. All
patents, published patent applications, and non-patent publications
referenced in any portion of this application are herein expressly
incorporated by reference in their entirety to the same extent as
if each individual patent or publication was specifically and
individually indicated to be incorporated by reference.
[0014] All of the articles and/or methods disclosed herein can be
made and executed without undue experimentation in light of the
present disclosure. While the articles and methods of the presently
disclosed and/or claimed inventive concept(s) have been described
in terms of preferred embodiments, it will be apparent to those of
ordinary skill in the art that variations may be applied to the
articles and/or methods and in the steps or in the sequence of
steps of the method described herein without departing from the
concept, spirit and scope of the presently disclosed and/or claimed
inventive concept(s). All such similar substitutes and
modifications apparent to those skilled in the art are deemed to be
within the spirit, scope and concept of the presently disclosed
and/or claimed inventive concept(s).
[0015] As utilized in accordance with the present disclosure, the
following terms, unless otherwise indicated, shall be understood to
have the following meanings.
[0016] The use of the word "a" or "an" when used in conjunction
with the term "comprising" may mean "one," but it is also
consistent with the meaning of "one or more," "at least one," and
"one or more than one." The use of the term "or" is used to mean
"and/or" unless explicitly indicated to refer to alternatives only
if the alternatives are mutually exclusive, although the disclosure
supports a definition that refers to only alternatives and
"and/or." Throughout this application, the term "about" is used to
indicate that a value includes the inherent variation of error for
the quantifying device, the method being employed to determine the
value, or the variation that exists among the study subjects. For
example, but not by way of limitation, when the term "about" is
utilized, the designated value may vary by plus or minus twelve
percent, or eleven percent, or ten percent, or nine percent, or
eight percent, or seven percent, or six percent, or five percent,
or four percent, or three percent, or two percent, or one percent.
The use of the term "at least one" will be understood to include
one as well as any quantity more than one, including but not
limited to, 1, 2, 3, 4, 5, 10, 15, 20, 30, 40, 50, 100, etc. The
term "at least one" may extend up to 100 or 1000 or more depending
on the term to which it is attached. In addition, the quantities of
100/1000 are not to be considered limiting as lower or higher
limits may also produce satisfactory results. In addition, the use
of the term "at least one of X, Y, and Z" will be understood to
include X alone, Y alone, and Z alone, as well as any combination
of X, Y, and Z. The use of ordinal number terminology (i.e.,
"first", "second", "third", "fourth", etc.) is solely for the
purpose of differentiating between two or more items and, unless
explicitly stated otherwise, is not meant to imply any sequence or
order or importance to one item over another or any order of
addition.
[0017] As used herein, the words "comprising" (and any form of
comprising, such as "comprise" and "comprises"), "having" (and any
form of having, such as "have" and "has"), "including" (and any
form of including, such as "includes" and "include") or
"containing" (and any form of containing, such as "contains" and
"contain") are inclusive or open-ended and do not exclude
additional, unrecited elements or method steps. The term "or
combinations thereof" as used herein refers to all permutations and
combinations of the listed items preceding the term. For example,
"A, B, C, or combinations thereof" is intended to include at least
one of: A, B, C, AB, AC, BC, or ABC and, if order is important in a
particular context, also BA, CA, CB, CBA, BCA, ACB, BAC, or CAB.
Continuing with this example, expressly included are combinations
that contain repeats of one or more item or term, such as BB, AAA,
AAB, BBC, AAABCCCC, CBBAAA, CABABB, and so forth. The skilled
artisan will understand that typically there is no limit on the
number of items or terms in any combination, unless otherwise
apparent from the context.
[0018] As used herein any reference to "one embodiment" or "an
embodiment" means that a particular element, feature, structure, or
characteristic described in connection with the embodiment is
included in at least one embodiment. The appearance of the phrase
"in one embodiment" in various places in the specification are not
necessarily all referring to the same embodiment.
[0019] As used herein, the term "copolymer" shall be defined as a
polymer(s) comprising two or more different monomers and should not
be construed to mean a polymer comprising only two different
monomers.
[0020] The presently disclosed and/or claimed inventive concept(s)
also encompasses a binder composition for use in a lithium ion
battery electrode comprising, consisting of, or consisting
essentially of a cross-linked polymer system comprising, consisting
of, or consisting essentially of an ionizable water soluble polymer
at least partially cross-linked with a component and at least one
of an esterification catalyst and an epoxy resin having at least
two epoxide groups. In one non-limiting embodiment, the binder
composition is substantially free of latex polymer. For example,
but without limitation, the binder composition is substantially
free of styrene butadiene latex polymer.
[0021] The ionizable water soluble polymer comprises a
polysaccharide having at least one hydroxyl group and, optionally,
one or more carboxyl groups. More specifically, the ionizable water
soluble polymer comprises, consists of, or consists essentially of
at least one of alginate, xanthan gum, polyvinyl alcohol, and an
anionically modified polysaccharide that can be selected from the
group consisting of carboxyalkyl cellulose, carboxyalkyl
hydroxyalkyl cellulose, carboxyalkyl guaran, carboxyalkyl
hydroxyalkyl guaran, and combinations thereof.
[0022] The carboxyalkyl guaran may be carboxymethyl guaran having a
carboxymethyl degree of substitution in a range of from about 0.1
to about 1.0, or from about 0.1 to 0.5, or from about 0.2 to about
0.4; and the carboxyalkyl hydroxyalkyl guaran may be carboxymethyl
hydroxypropyl guaran having a carboxymethyl degree of substitution
in a range of from about 0.1 to about 1.0, or from about 0.1 to
0.5, or from about 0.2 to about 0.4 and a hydroxypropyl molar
substitution in a range of from about 0.1 to about 1.0, or from
about 0.2 to about 0.7, or from about 0.2 to about 0.4.
[0023] The carboxyalkyl cellulose may be carboxymethyl cellulose
having a carboxymethyl degree of substitution in a range of from
about 0.1 to about 1.2, or from about 0.5 to about 1.0, or from
about 0.7 to about 0.95; and the carboxyalkyl hydroxyalkyl
cellulose may be carboxymethyl hydroxyethyl cellulose having a
carboxymethyl degree of substitution in a range of from about 0.1
to about 1.0, or from about 0.1 to 0.5, or from about 0.2 to about
0.4 and a hydroxypropyl molar substitution in a range of from about
0.1 to about 1.0, or from about 0.2 to about 0.7, or from about 0.2
to about 0.4.
[0024] In one embodiment, the ionizable water soluble polymer
comprises, consists of, or consists essentially of at least one of
a lithiated alginate, lithiated xanthan gum, lithiated polyvinyl
alcohol, and a lithiated anionically modified polysaccharide that
can be selected from the group consisting of lithiated carboxyalkyl
cellulose, lithiated carboxyalkyl cellulose, lithiated carboxyalkyl
guaran, lithiated carboxyalkyl hydroxyalkyl guaran, and
combinations thereof.
[0025] The component may be a synthetic polymer comprising at least
one carboxyl group. More specifically, the synthetic polymer can be
selected from the group consisting of polyacrylic acid, polyacrylic
acid copolymers, methyl vinyl ether and maleic anhydride
copolymers, modified methyl vinyl ether and maleic anhydride
copolymers, styrene maleic anhydride copolymers, and combinations
thereof. The component can also be polycarboxylic acids.
[0026] The methyl vinyl ether and maleic anhydride copolymer (also
referred to herein as "MVE/MA copolymer(s)") have molecular weights
in a range of from about 100,000 to about 3,000,000 Daltons, which
are available from Ashland Inc., Covington, Ky. as Gantrez.TM.
polymers.
[0027] In one embodiment, the methyl vinyl ether and maleic
anhydride copolymers are in a basic solution or in the form of a
lithium salt, such that the copolymer may be at least one of a
sodium salt of methyl vinyl ether and maleic anhydride copolymer,
and a lithium salt of methyl vinyl ether and maleic anhydride
copolymer.
[0028] The modified methyl vinyl ether and maleic anhydride
copolymers (hereinafter also referred to as "modified MVE/MA
copolymer(s)") can be prepared from polymerizing methyl vinyl
ether, maleic anhydride, and at least one component selected from
the group consisting of octylamine, polyetheramines,
acrylonitriles, fluorinated vinyl ether, isobutylene, and
combinations thereof.
[0029] The modified MVE/MA copolymer may be a copolymer prepared
from polymerizing octylamine, methyl vinyl ether, and maleic
anhydride, wherein the octylamine is present in a range of from
about 5 to about 40 mol %, or from about 10 to about 35 mol %, or
from about 15 to about 30 mol %; the methyl vinyl ether is present
in a range of from about 40 to about 60 mol %, or from about 45 to
about 55 mol %; and the maleic anhydride is present in a range of
from about 30 to about 70 mol %, or from about 40 to about 60 mol
%, or from about 45 to about 55 mol %.
[0030] The modified MVE/MA copolymer may also be a copolymer
prepared from polymerizing a polyetheramine, methyl vinyl ether,
and maleic anhydride, wherein the polyetheramine is present in a
range of from about 10 to about 40 mol %, or from about 15 to about
35 mol %, or from about 20 to about 30 mol %; the methyl vinyl
ether is present in a range of from about 40 to about 60 mol %, or
from about 45 to about 55 mol %; and the maleic anhydride is
present in a range of from about 30 to about 70 mol %, or from
about 40 to about 60 mol %, or from about 45 to about 55 mol %.
[0031] The modified MVE/MA copolymer may be a copolymer prepared
from polymerizing isobutylene, methyl vinyl ether, and maleic
anhydride, wherein the isobutylene is present in a range of from 10
to about 40 mol %, or from about 15 to about 35 mol %, or from
about 20 to about 30 mol %; the methyl vinyl ether is present in a
range of from 40 to about 60 mol %, or about 45 to about 55 mol %,
and the maleic anhydride is present in a range of from about 30 to
about 70 mol %, or from about 40 to about 60 mol %, or from about
45 to about 55 mol %.
[0032] The modified MVE/MA copolymer may also be a copolymer
prepared from polymerizing octylamine, isobutylene, methyl vinyl
ether, and maleic anhydride, wherein the octylamine is present in a
range of from about 5 to about 40 mol %, or from about 10 to about
35 mol %, or from about 15 to about 30 mol %; the isobutylene is
present in a range of from 10 to about 40 mol %, or from about 15
to about 35 mol %, or from about 20 to about 30 mol %; the methyl
vinyl ether is present in a range of from about 40 to about 60 mol
%, or from about 45 to about 55 mol %; and the maleic anhydride is
present in a range of from about 30 to about 70 mol %, or from
about 40 to about 60 mol %, or from about 45 to about 55 mol %.
[0033] The modified MVE/MA copolymer may be a copolymer prepared
from polymerizing fluorinated vinyl ether, methyl vinyl ether, and
maleic anhydride, wherein the fluorinated vinyl ether is present in
a range of from about 5 to about 40 mol %, or from about 5 to about
35 mol %, or from about 5 to about 30 mol %; the methyl vinyl ether
is present in a range of from about 35 to about 65 mol %, or from
about 40 to about 60 mol %, or from about 45 to about 55 mol %; and
the maleic anhydride is present in a range of from about 10 to
about 60 mol %, or from about 15 to about 55 mol %, or from about
20 to about 45 mol %.
[0034] The modified MVE/MA copolymer may be a copolymer prepared
from polymerizing an acrylonitrile, methyl vinyl ether, and maleic
anhydride, wherein the acrylonitrile is present in a range of from
about 10 to about 50 mol %, or from about 15 to about 40 mol %, or
from about 20 to about 35 mol %; the methyl vinyl ether is present
in a range of from about 35 to about 65 mol %, or from about 40 to
about 60 mol %, or from about 45 to about 55 mol %; and the maleic
anhydride is present in a range of from about 5 to about 40 mol %,
or from about 10 to about 35 mol %, or from about 15 to about 30
mol %.
[0035] The polyacrylic acid copolymer can be selected from the
group consisting of a copolymer of acrylic acid and methacrylic
acid, a copolymer of alkylacrylates and acrylic acid, a copolymer
of alkylacrylates and methacrylic acid, and combinations
thereof.
[0036] The styrene maleic anhydride copolymer may be unmodified
styrene maleic anhydride and/or one or more modified styrene maleic
anhydride compositions selected from the group consisting of
ester-modified styrene maleic anhydride copolymers,
alcohol-modified styrene maleic anhydride copolymers,
amine-modified styrene maleic anhydride copolymers, and
combinations thereof.
[0037] The polycarboxylic acids are at least one of (i) in a basic
solution, and (ii) lithiated, wherein the lithiated polycaboxylic
acids are formed by adding the polycarboxylic acids to a lithium
hydroxide solution. In one embodiment, the polycarboxylic acid
comprises at least one of (i) a sodium salt of the polycarboxylic
acid, and (ii) a lithium salt of the polycarboxylic acid. The
polycarboxylic acids can be selected from the group consisting of
formic acid, acetic acid, chloroacetic acid, dichloroacetic acid,
trichloroacetic acid, trifluoroacetic acid, oxalic acid, benzoic
acid, and combinations thereof, wherein the polycarboxylic acids
are at least one of (i) in a basic solution, and (ii)
lithiated.
[0038] In an alternative non-limiting embodiment, the synthetic
polymer can be lithiated. For example, but without limitation, the
lithiated synthetic polymer can be selected from the group
consisting of lithiated polyacrylic acid, a lithiated polyacrylic
acid copolymer, lithiated methyl vinyl ether and maleic anhydride
copolymers, lithiated modified methyl vinyl ether and maleic
anhydride copolymers, lithiated styrene maleic anhydride
copolymers, lithiated polyvinyl alcohol, and combinations
thereof.
[0039] In one embodiment, the binder composition comprises a
cross-linked polymer system formed by an esterification reaction
between at least one hydroxyl group of the above-described
ionizable water soluble polymer and at least one carboxyl group of
the above-described component in the presence of an esterification
catalyst.
[0040] In another non-limiting embodiment, the binder composition
comprises a cross-linked polymer system formed by an esterification
reaction between at least one carboxyl group of the above-described
component and at least one hydroxyl group of at least one of (i)
the above-described ionizable water soluble polymer and (ii) a
silicon-containing electrode active material (described below), in
the presence of an esterification catalyst.
[0041] In yet another embodiment, the binder composition comprises
a cross-linked polymer system formed by an esterification reaction
between (1) at least one carboxyl group of at least one of (a) the
above-described component and (b) the above-described ionizable
water soluble polymer, and (2) at least one hydroxyl group of at
least one of (a) the above-described ionizable water soluble
polymer and (b) a silicon-containing electrode active material
(described below).
[0042] The esterification catalyst may be selected from the group
consisting of sodium hypophosphite, sulphonic acid, methane
sulphonic acid, trifluoromethane sulphonic acid, titanate esters,
dialkyl tin, and combinations thereof. The titanate ester can be,
for example but without limitation, tetrabutyl titanate. In one
non-limiting embodiment, the esterification catalyst is sodium
hypophosphite.
[0043] The esterification reaction is driven by removal of water
from an aqueous solution comprising the above-described ionizable
water soluble polymer, the above-described component, an
esterification catalyst, and, optionally an electrode active
material.
[0044] As such, the presently disclosed and/or claimed inventive
concept(s) also encompasses a binder composition for use in a
lithium ion battery electrode comprising, consisting of, or
consisting essentially of a cross-linked polymer system comprising,
consisting of, or consisting essentially of an ionizable water
soluble polymer at least partially cross-linked in situ with a
component, and further comprising, consisting of, or consisting
essentially of an esterification catalyst.
[0045] In one embodiment, a binder composition comprises a
cross-linked polymer system formed by the reaction of an epoxy
resin with at least one of an ionizable water soluble polymer and a
component, wherein (i) at least one epoxide group of the epoxy
resin reacts with at least one hydroxyl group of the ionizable
water soluble polymer and (ii) at least one epoxide group of the
epoxy resin reacts with at least one carboxyl group of the
component.
[0046] In another embodiment, a binder composition comprises a
cross-linked polymer system formed by the reaction of an epoxy
resin with at least one of an ionizable water soluble polymer, a
component, and an electrode active material, wherein (i) at least
one epoxide group of the epoxy resin reacts with at least one
hydroxyl group of the ionizable water soluble polymer and (ii)
wherein (a) at least one epoxide group of the epoxy resin reacts
with at least one carboxyl group of the component, and/or (b) at
least one epoxide group of the epoxy resin reacts with at least one
hydroxyl group on the surface of the electrode active material.
[0047] In one non-limiting embodiment, the binder composition
comprises a cross-linked polymer system formed by the reaction of
an epoxy resin with at least one of an ionizable water soluble
polymer, a component, and an electrode active material, wherein (i)
at least one epoxide group of the epoxy resin reacts with at least
one hydroxyl group of the ionizable water soluble polymer and (ii)
wherein (a) at least one epoxide group of the epoxy resin reacts
with at least one carboxyl group of the component, and/or (b) at
least one epoxide group of the epoxy resin reacts with at least one
hydroxyl group on the surface of the electrode active material,
and/or (c) at least one epoxide group of the epoxy resin reacts
with at least one carboxyl group of the ionizable water soluble
polymer. Additionally, an epoxy cross-linking catalyst can be added
during the formation of the cross-linked polymer system to catalyze
the reaction between the at least one epoxide group of the epoxy
resin with the at least one hydroxyl group of the ionizable water
soluble polymer and/or the at least one hydroxyl group on the
surface of the electrode active material.
[0048] In another non-limiting embodiment, the binder composition
is formed by the reaction of an epoxy resin with at least one of an
ionizable water soluble polymer and a component, wherein (i) at
least one epoxide group of the epoxy resin reacts with at least one
hydroxyl group of the ionizable water soluble polymer and (ii) at
least one epoxide group of the epoxy resin reacts with at least one
carboxyl group of the component, in the presence of an epoxy
cross-linking catalyst.
[0049] More specifically, in one non-limiting embodiment, the
binder composition comprises a cross-linked polymer system formed
by combining an epoxy resin having at least two epoxide groups with
an ionizable water soluble polymer, a component, and optionally an
electrode active material, in an aqueous dispersion, wherein drying
the aqueous dispersion drives (i) at least one epoxide group of the
epoxy resin to react with at least one hydroxyl group of the
ionizable water soluble polymer and (ii) at least one epoxide group
of the epoxy resin to react with at least one of (a) a hydroxyl
group of the electrode active material and (b) a carboxyl group of
at least one of the component and the ionizable water soluble
polymer in the presence of an epoxy cross-linking catalyst. The
reaction between the epoxy resin, the ionizable water soluble
polymer, and the component is driven by the removal of water from
the aqueous solution comprising an epoxy resin, an ionizable water
soluble polymer, a component, and, optionally, an electrode active
material.
[0050] The epoxy cross-linking catalyst can be selected from the
group consisting of tertiary amines, quaternary amines, imidazoles,
phosphonium compounds, chelates, and combinations thereof. The
chelates can be, for example but without limitation, zinc chelates,
available from King Industries (Norwalk, Conn.) as NACUR.RTM.
XC-9206.
[0051] In one non-limiting embodiment, the epoxy cross-linking
catalyst comprises an imidazole. The imidazole comprises
2-methylimidazole or 2-ethylimidazole. The epoxy cross-linking
catalyst can also be selected from those disclosed in the
publication, W. Blank et al., "Catalyst if the Epoxy-Carboxyl
Reaction", presented at the International Waterborne, High-Solids
and Powder Coatings Symposium, Feb. 21-23, 2001, New Orleans, La.
USA, which is hereby incorporated herein by reference in its
entirety.
[0052] The epoxy resin has at least two epoxide groups, wherein the
epoxy resin comprises, consists of, or consists essentially of at
least one di-epoxy, tri-epoxy, tetra-epoxy, and combinations
thereof. The epoxy resin can be bisphenol A diepoxy.
[0053] The epoxy resin in an aqueous dispersion further comprises
at least one surfactant, wherein the surfactant can also be
referred to herein as a dispersant or emulsifier. The surfactant
can be selected from the group consisting of phosphate esters,
complex coesters comprising a sodium or potassium salt of an
orthophosphate or polyphosphate ester of an alcohol and an adduct
of ethylene oxide, imidazolines, amides and combinations
thereof.
[0054] The phosphate ester can be an organic phosphate ester
including complex organic orthophosphate or polyphosphate ester
acid and its salt. The surfactant may also be selected from those
disclosed in U.S. Pat. No. 5,623,046, U.S. Pat. No. 3,301,804
(employing the reaction product of a boric acid with both an
alkylene glycol and beta-dialkyl-substituted aminoalkanol as an
emsulsifier), U.S. Pat. No. 3,634,348 (employing a phosphate ester
as an emulsifying agent), U.S. Pat. No. 3,249,412 (employing in
combination a cationic emulsifying agent selected from the group
consisting of imidazolines and amides and a non-ionic emulsifying
agent), and Specialty Chemicals Bulletin SC-201 entitled
"Water-Reducible Coatings via Epoxy Resin Modification with
Jeffamine.RTM. ED-2001 and Jeffamine.RTM. M-1000" available from
Texaco Chemical Company (Bellaire, Tex.), all of which are hereby
incorporated herein by reference in their entirety. In one
embodiment, the aqueous epoxy resin dispersion is a non-ionic
aqueous dispersion of bisphenol A diepoxy available as EPI-REZ.RTM.
6520-WH-53 available from Momentive Specialty Chemicals (Columbus,
Ohio).
[0055] As such, the presently and/or claimed inventive concept(s)
also encompasses a binder composition for use in a lithium ion
battery electrode comprising, consisting of, or consisting
essentially of a cross-linked polymer system comprising, consisting
of, or consisting essentially of an ionizable water soluble polymer
at least partially cross-linked with a component and, optionally,
an electrode active material, and further comprising, consisting
of, or consisting essentially of an epoxy resin.
[0056] In one embodiment, the electrode active material can be an
anode active material. The anode active material can be any
material comprising, consisting of, or consisting essentially of
(1) at least one of an artificial graphite, a natural graphite,
surface modified graphite, coke, hard carbon, soft carbon, carbon
fiber, conductive carbon, and combinations thereof, (2)
silicon-based alloys, (3) complex compounds comprising, consisting
of, or consisting essentially of: i) at least one of artificial
graphite, natural graphite, surface modified graphite, coke, hard
carbon, soft carbon, carbon fiber, conductive carbon and
combinations thereof, and ii) a metal selected from the group
consisting of Al, Ag, Bi, In, Ge, Mg, Pb, Si, Sn, Ti, and
combinations thereof, (4) a lithium complex metal oxide, (5)
lithium-containing nitrides, (6) silicon-graphene, (7) a
silicon-carbon nanotube, (8) silicon oxide, and (9) combinations
thereof.
[0057] The anode active material, in one non-limiting embodiment,
can be selected from the group consisting of artificial graphite,
natural graphite, surface modified graphite, coke, hard carbon,
soft carbon, carbon fiber, conductive carbon, and combinations
thereof. In another non-limiting embodiment, the anode active
material comprises a complex compound comprising, consisting of, or
consisting essentially of (i) at least one of artificial graphite,
natural graphite, surface modified graphite, coke, hard carbon,
soft carbon, carbon fiber, conductive carbon, and combinations
thereof, and (ii) silicon and/or silicon oxide. The anode active
material, in another non-limiting embodiment, can comprise, consist
of, or consist essentially of lithium titanate
(Li.sub.4Ti.sub.5O.sub.12).
[0058] In one embodiment, the anode active material can be silicon
oxide. In an additional non-limiting embodiment, the anode active
material can be a mixture of graphite and silicon oxide, wherein
the silicon oxide can, for example but without limitation, be
represented by the formula SiO.sub.x, wherein 2<X.ltoreq.1, and
further wherein the weight ratio of graphite to silicon oxide may
be at least 50:50, or in a range of from about 70:30 to about 99:1,
or from about 80:20 to about 95:5, or from about 90:10 to about
95:5. In one embodiment, the above-described anode active material
comprising graphite and silicon oxide can also comprise conductive
carbon in a range from about 0.1 to about 10 wt %, or from about 1
to about 8 wt %, or from about 2 to about 5 wt %.
[0059] In another non-limiting embodiment, the anode active
material may comprise a silicon-graphene composition and/or a
combination of a silicon-graphene composition and graphene. See,
for example but without limitation, the XG-SIG.TM. silicon-graphene
nano-composite material available from XG Sciences, Inc. (Lansing,
Mich.). In yet another non-limiting embodiment, the electrode
active material may comprise a silicon alloy, for example but
without limitation, silicon titanium nickel alloy (STN), and/or a
mixture of a silicon alloy and graphite. More specifically, the
electrode active material may comprise silicon alloy and graphite
mixture, wherein the silicon alloy is present in a range of from
about 30 to 50 wt %, or from about 35 to about 45 wt %, or from
about 37.5 to about 42.5 wt %, and wherein the graphite is present
in a range from about 50 to about 70 wt %, or from about 55 to
about 65 wt % or from about 57.5 to about 62.5 wt %.
[0060] In one embodiment, the above-described anode active material
may comprise a silicon-graphene composition and/or a combination of
a silicon graphene composition and graphite, further comprising
conductive carbon. More specifically, the anode active material may
comprise silicon-graphene and graphite and/or conductive carbon,
wherein the silicon-graphene is present in a range of from about 20
to 95 wt %, or from about 70 to 95 wt %, or from about 75 to 95 wt
%, or from about 80 to about 95 wt %, and wherein the graphite is
present in a range of from about 5 to about 30 wt %, or from about
10 to about 25 wt %, or from about 10 to about 20 wt %, and wherein
the conductive carbon is present in a range of from about 1 to
about 10 wt %, or from about 1 to about 8 wt %, or form about 1 to
about 5 wt %.
[0061] The anode active material can have at least one hydroxyl
group on its surface. In one embodiment, the anode active material
comprises a silicon-containing material, wherein the
silicon-containing material comprises hydroxyl groups in a range of
from about 1 to about 4 wt %, or from about 1 to about 3 wt %, or
from about 1 to about 2 wt %. The hydroxyl moieties on the surface
of a silicon-containing anode active material are able to react
with the carboxyl groups of the above-described component and/or
the above-described ionizable water soluble polymer by means of a
condensation reaction.
[0062] In another non-limiting embodiment, the electrode active
material can be a cathode active material. The cathode active
material can be any material comprising, consisting of, or
consisting essentially of lithium-containing transition metal
oxides. The cathode active material, in one non-limiting
embodiment, can be selected from the group consisting of lithium
iron phosphate (LiFePO.sub.4), lithium cobalt oxide (LiCoO.sub.2),
lithium nickel oxide (LiNiO.sub.2), lithium nickel cobalt aluminum
oxide (LiNiCoAlO.sub.2), lithium nickel manganese cobalt oxide
(LiNiMnCoO.sub.2), lithium manganese oxide (LiMn.sub.2O.sub.4), and
combinations thereof.
[0063] The presently disclosed and/or claimed inventive concept(s)
additionally encompasses a slurry for preparation of a lithium ion
battery comprising, consisting of, or consisting essentially of an
electrode active material, an ionizable water soluble polymer (as
described above), a component (as described above), and at least
one of an esterification catalyst (as described above) and/or an
epoxy resin (as described above). In one embodiment, the slurry can
further comprise a cross-linking catalyst in a range from about 0.1
to about 1 wt %, or from about 0.3 to about 0.6 wt %, or from about
0.4 to about 0.6 wt %.
[0064] In one embodiment, the ionizable water soluble polymer and
the component can be present in the above-described slurry in a
range of from about 1 to about 5 wt % of solids, or from about 1.5
to about 4 wt % of solids, or from about 2 to about 3 wt % of
solids; the electrode active material can be present a range of
from about 15 to about 65 wt % of solids, or from about 20 to about
40 wt % of solids, or from about 24 to about 36 wt % of solids; the
epoxy resin can be present in a range of from about 2 wt % to about
60 wt % of solids, or from about 5 to about 50 wt % of solids, or
from about 10 to about 30 wt % of solids; and the water can be
present in a range of from about 30 to about 90 wt % of slurry, or
from about 35 to about 85 wt % of solids of slurry, or from about
40 to about 75 wt % of slurry.
[0065] In another embodiment, the ionizable water soluble polymer
can be present in the above described slurry in a range of from
about 0.1 to about 5 wt % of solids, or from about 0.25 to about 4
wt % of solids, or from about 0.4 to about 3 wt % of solids; the
component can be present in a range of from about 0.1 to about 5 wt
% of solids, or from about 0.25 to about 4 wt % of solids, or from
about 0.4 to about 3 wt % of solids; the electrode active material
can be present in a range of from about 15 to about 65 wt % of
solids, or from about 20 to about 40 wt % of solids, or from about
24 to about 36 wt % of solids; the epoxy resin can be present in a
range of from about 2 wt % to about 60 wt % of solids, or from
about 5 to about 50 wt % of solids, or from about 10 to about 30 wt
% of solids; and the water can be present in a range of from about
30 to about 90 wt % of slurry, or from about 35 to about 85 wt % of
slurry, or from about 40 to about 75 wt % of slurry.
[0066] In an alternative embodiment, the ionizable water soluble
polymer (as described above) and the component can be present in
the above-described slurry in a range of from about 1 to about 5 wt
% of solids, or from about 1.5 to about 4 wt % of solids, or from
about 2 to about 3 wt % of solids; the electrode active material
can be present a range of from about 15 to about 65 wt % of solids,
or from about 20 to about 40 wt % of solids, or from about 24 to
about 36 wt % of solids; the esterification catalyst can be present
in a range of from about 0.005 to about 5 wt % of solids, or from
about 0.05 to about 4 wt % of solids, or from about 1 to about 3 wt
% of solids; and the water can be present in a range of from about
30 to about 90 wt % of slurry, or from about 35 to about 85 wt % of
slurry, or from about 40 to about 75 wt % of slurry.
[0067] In yet another embodiment, the ionizable water soluble
polymer (as described above) is present in the above-described
slurry in a range of from about 0.1 to about 5 wt % of solids, or
from about 0.25 to about 4 wt % of solids, or form about 0.4 to
about 3 wt % of solids; the component is present in a range of from
about 0.1 to about 5 wt % of solids, or from about 0.25 to about 4
wt % of solids, or from about 0.4 to about 3 wt % of solids; the
electrode active material is present in a range of from about 15 to
about 65 wt % of solids, or from about 20 to about 40 wt % of
solids, or from about 24 to about 36 wt % of solids; the
esterification catalyst is present in a range of from about 0.005
to about 5 wt % of solids, or from about 0.05 to about 4 wt % of
solids, or from about 1 to about 3 wt % of solids; and the water
can be present in a range of from about 30 to about 90 wt % of
slurry, or from about 35 to about 85 wt % of slurry, or from about
40 to about 75 wt % of slurry.
[0068] In one embodiment, the above-described slurry has a
Brookfield.RTM. viscosity in a range of from about 3,000 to about
15,000 mPas, or from about 3,000 to about 10,000 mPas, or from
about 4,000 to about 9,000 mPas, as measured at 30 RPMs with
spindle #4 at ambient conditions.
[0069] The above-described slurries have a good stability, wherein
the slurries can visibly stay in solution for at least 24 hours, or
for at least 3 days, or for at least 5 days. As such, the
above-described binder compositions of the slurry are soluble in
water until the slurry is dried, which drives the above-described
esterification reaction and/or the above-described cross-linking
reaction with the epoxy resin.
[0070] The slurry is dried at room temperature and/or heated to
evaporate the water in the slurry, driving the above-described
esterification reaction(s) and/or cross-linking with the epoxy
resin, and thereby forming a film comprising the above-described
electrode active material and the above-described cross-linked
polymer system.
[0071] In one embodiment, the slurry is dried at a temperature in a
range of from about 80 to about 175.degree. C., or from about 100
to about 150.degree. C. for a time in a range of from about 0.5 to
about 3 hours, or from about 1 to about 2 hours. In another
embodiment, the slurry is first dried at a temperature from about
80 to about 125.degree. C., or from about 90 to about 110.degree.,
or from about 95 to about 105.degree. C. for at most 1 hour, or at
most 0.75 hour, or at most 0.5 hour; and dried a second time at a
temperature from about 80 to about 175.degree. C., or from about
125 to about 165.degree. C., or from about 145 to about 155.degree.
C. for about 1 to about 3 hours, or from about 1.5 to about 2.5
hours, or from about 1.75 to about 2.25 hours.
[0072] The presently disclosed and/or claimed inventive concept(s)
also encompasses a film for use in preparation of a lithium ion
battery, comprising (i) a binder composition comprising a
cross-linked polymer system comprising an ionizable water soluble
polymer cross-linked in situ with a component in the presence of an
esterification catalyst and/or an epoxy resin having two or more
epoxide groups, and (ii) an electrode active material. It is also
contemplated, in one non-limiting embodiment, that the film can be
prepared by combining an ionizable water soluble polymer with (i) a
component, (ii) an electrode active material, and (iii) at least
one of a esterification catalyst and/or an epoxy resin having two
or more epoxide groups in water to form a slurry, which is
thereafter dried, wherein the drying step drives the formation of
the cross-linked polymer system.
[0073] The presently disclosed and/or claimed inventive concept(s)
further encompasses an electrode for use in a lithium ion battery
comprising (i) a film comprising: (1) an electrode active material,
and (2) a binder composition comprising a cross-linked polymer
system comprising an ionizable water soluble polymer cross-linked
in situ with a component in the presence of an esterification
catalyst and/or an epoxy resin having two or more epoxide groups,
and (ii) a current collector.
[0074] The presently disclosed and/or claimed inventive concept(s)
additionally encompasses a method of making an electrode for a
lithium ion battery comprising the steps of: (1) combining an
electrode active material, an ionizable water soluble polymer, a
component, an esterification catalyst and/or an epoxy resin having
two or more epoxide groups, and water to form a slurry; (2)
applying the slurry to a current collector to form a coated current
collector comprising a slurry layer on the current collector; and
(3) drying the slurry layer on the coated current collector to form
a film on the current collector, wherein the film comprises (i) a
binder composition comprising a cross-linked polymer system
comprising the ionizable water soluble polymer cross-linked in situ
with the component, wherein the cross-linked polymer system is
formed in the presence of an esterification catalyst and/or an
epoxy resin having two or more epoxide groups during the drying
step, and (ii) the electrode active material, and wherein the
electrode comprises the film and the current collector.
[0075] In one embodiment, the above-described film comprises the
ionizable water soluble polymer and the component each in a range
of from about 0.1 to about 20 wt %, or from about 0.5 to about 15
wt %, or from about 1 to about 10 wt %; the electrode active
material is present in the film in a range of from about 65 to
about 99 wt %, or from about 70 to about 98.5 wt %, or from about
75 to about 98 wt %; and the esterification catalyst is present in
an amount of 0.5 to about 3 wt %, or from about 1 to about 3 wt %,
or from about 1.5 to about 2.5 wt %.
[0076] In an alternative embodiment, the above-described film
comprises the ionizable water soluble polymer and the component
each in a range of from about 0.1 to about 20 wt %, or from about
0.5 to about 15 wt %, or from about 1 to about 10 wt %; the
electrode active material is present in the film in a range of from
about 65 to about 99 wt %, or from about 70 to about 98.5 wt %, or
from about 75 to about 98 wt %; and the epoxy resin is present in
an amount of from about 10 to about 30 wt %, or from about 10 to
about 20 wt %, or from about 12 to about 17 wt %. The film can
further comprise the above-described epoxy cross-linking catalyst
in a range of from about 0.01 to about 3 wt %, or from about 0.5 to
about 2 wt %, or from about 1 to about 1 wt %.
[0077] Additionally, the presently disclosed and/or claimed
inventive concept(s) encompasses an electrode comprising,
consisting of, or consisting essentially of (i) a film (as
described above) comprising, consisting of, or consisting
essentially of (1) an electrode active material (as described
above), and (2) the above-described binder composition comprising,
consisting of, or consisting essentially of a cross-linked polymer
system comprising, consisting of, or consisting essentially of an
ionizable water soluble polymer at least partially cross-linked
with a component (as described above), and (ii) a current
collector.
[0078] The film has a thickness in a range of from about 10 to
about 100 .mu.m, about 10 to about 60 .mu.m, or from about 15 to
about 50 .mu.m, or from about 20 .mu.m to about 30 .mu.m.
[0079] The above-described film has good electrolyte resistance
properties, as evidence by the electrochemical properties presented
in the following Examples.
[0080] The current collector can be any material that acts as an
electrical conductor for an anode material. For example, the
current collector can be made of the materials selected from the
group consisting of aluminum, carbon, copper, stainless steel,
nickel, zinc, silver, and combinations thereof. In one non-limiting
embodiment, the current collector for the anode is a copper
foil.
[0081] The above-described electrode film can be bound to a surface
of the above-described current collector to form a bond. In one
non-limiting embodiment, the adhesive strength of the bond is at
least about 0.3 gf/mm, or at least about 0.4 gf/mm, or at least
about 0.5 gf/mm.
EXAMPLES
Slurry Preparations for Viscosity and Adhesion Tests
[0082] Slurries were prepared using different formulations for the
binder compositions, as presented in Table 1. For each sample in
Table 1, the anode active material comprised (i) graphite having an
initial capacity of about 350 mAh/g, (ii) a powder mixture of
graphite and silicon oxide in a weight ratio of 92:5 graphite to
silicon oxide, wherein the anode active material had a range of
about 430 to about 450 mAh/g initial capacity, (iii) a powder
mixture of natural graphite, silicon oxide, SiO.sub.x, and
conductive carbon having an initial capacity of about 600 mAh/g, or
(iv) a powder mixture of silicon-graphene and conductive carbon
having an initial capacity of about 600 mAh/g. The graphite
comprised natural graphite available from BTR Energy Materials Co.,
LTD (Shenzhen, China), the silicon oxide, SiO.sub.x, is available
from Osaka Titanium Technologies Co., Ltd. (Amagasaki, Hyogo
Prefecture, Japan), the silicon-graphene is available from XG
Sciences, Inc. (Lansing, Mich.), and the conductive carbon is
C-NERGY.TM. Super C65 available from Timcal Graphite & Carbon
(Bodio, Switzerland). Additionally, as illustrated in Table 1, the
water content varied for each sample and was calculated as a total
weight percent of the water in the slurry composition whether added
as a binder composition solution or otherwise. The contents of the
components were presented based on the total weights of the
slurries. The components of the binder compositions were varied, as
indicated in Table 1, wherein examples that do not comprise an
esterification catalyst and/or epoxy resin comprising at least two
epoxide groups are for comparative purposes and, as such, are
labeled as "reference" samples.
[0083] The samples in Table 1 were formed by: (1) adding the anode
active material to an aqueous solution of components of a selected
binder composition, (2) adding additional water and stirring by
hand until the composition forms a paste, (3) mixing the
composition for 3 minutes with a Thinky.RTM. mixer (available from
Thinky Corporation, Tokyo, Japan), (4) adding additional water and
mixing for 3 minutes with the Thinky.RTM. mixture, (5) adding
another amount of water to the composition and mixing for 3 minutes
with the Thinky.RTM. mixture, and (6) checking the slurry quality
and mixing for an additional minute with the Thinky.RTM. mixture,
if necessary. The amounts of water added to form each sample can be
determined from the weight percents provided in Table 1.
TABLE-US-00001 TABLE 1 Component Ionizable Water soluble Polymer
(wt. ratio, if Esterification Electrode Active (wt. ratio, if
multiple) multiple) Catalyst Epoxy Resin Material Water Sample #
(wt %) (wt %) (wt % ) (wt % ) (wt % ) (wt % ) 1 GW-45 Carboxymethyl
Guaran -- -- -- 450 mAh/g 71.7 (com- (0.69) Graphite/SiO.sub.x
parative) (27.6) 2 Aqu D-5284 Carboxymethyl Cellulose/ -- -- -- 450
mAh/g 61.7 (com- Ambergum .TM. Carboxymethyl Cellulose
Graphite/SiO.sub.x(37.4) parative) (2/1) (0.93) 3 Aqu D-5284
Carboxymethyl Cellulose/ -- -- -- 450 mAh/g 66.4 (com- Ambergum
.TM. Carboxymethyl Cellulose/ Graphite/SiO.sub.x parative) GW-45
Carboxymethyl Guaran (32.8) (0.67/0.33/1.5) (0.82) 4 Aqu D-5284
Carboxymethyl Cellulose/ Aqu D-5882 -- -- 450 mAh/g 58.2 (com-
Ambergum .TM. Carboxymethyl Cellulose/ Polyacrylic Acid
Graphite/SiO.sub.x parative) Aqu D-5592 Polyacrylic Acid (0.61)
(40.8) (0.67/0.33/1.5) (0.4) 5 WG-18 Carboxymethyl -- -- -- 450
mAh/g 70.0 (com- Hydroxypropyl Guaran Graphite/SiO.sub.x parative)
(0.73) (29.3) 6 Aqu D-5284 Carboxymethyl Cellulose/ -- -- -- 450
mAh/g 65.8 (com- Ambergum .TM. Carboxymethyl Cellulose/
Graphite/SiO.sub.x parative) WG-18 Carboxymethyl Hydroxypropyl
(33.3) Guaran (0.67/0.33/1.5) (0.83) 7 Kelset .RTM. NF Alginate --
-- -- 450 mAh/g 73.8 (com- (0.64) Graphite/SiO.sub.x parative)
(25.5) 8 Aqu D-5284 Carboxymethyl Cellulose/ -- -- -- 450 mAh/g
68.5 (com- Ambergum .TM. Carboxymethyl Cellulose/
Graphite/SiO.sub.x parative) Kelset .RTM. NF Alginate (30.8)
(0.67/0.33/1.5) (0.77) 9 Xanthan Gum -- -- -- 450 mAh/g 70.0 (com-
(0.73) Graphite/SiO.sub.x parative) (29.3) 10 Aqu D-5284
Carboxymethyl Cellulose/ -- -- -- 450 mAh/g 65.8 (com- Ambergum
.TM. Carboxymethyl Cellulose/ Graphite/SiO.sub.x parative) Xanthan
Gum (33.3) (0.67/0.33/1.5) (0.83) 11 Kelcosol .RTM. Alginate -- --
-- 450 mAh/g 66.0 (com- (0.83) Graphite/SiO.sub.x parative) (33.1)
12 Manosol .RTM. HV Alginate -- -- -- 450 mAh/g 66.0 (com- (0.83)
Graphite/SiO.sub.x parative) (33.1) 13 Lithiated Alginate F120 NM
-- -- -- 450 mAh/g 56.4 (com- (1.28) Graphite/SiO.sub.x parative)
(42.6) 14 Aqu D-5284 Carboxymethyl Cellulose/ -- -- -- 450 mAh/g
50.0 (com- Ambergum .TM. Carboxymethyl Cellulose/
Graphite/SiO.sub.x parative) Lithiated Alginate F120NM (48.8)
(0.67/0.33/1.5) (1.22) 15 Kelcosol .RTM. Alignate/Lithiated
Alginate -- -- -- 450 mAh/g 57.7 (com- (1/1.5) Graphite/SiO.sub.x
parative) (1.04) (41.2) 16 GW-3 Guaran -- -- -- 450 mAh/g 71.7
(com- (0.69) Graphite/SiO.sub.x parative) (27.6) 17 GW-3 Guaran Aqu
D-5529 Sodium -- 450 mAh/g 74.6 (0.45) Polyacrylic Acid
Hypophosphite Graphite/SiO.sub.x (0.15) (0.05) (24.8) 18 GW-3
Guaran Lithiated Sodium -- 450 mAh/g 81.6 (0.33) Polyacrylic Acid
Hypophosphite Graphite/SiO.sub.x (MW = 1.25 MM) (0.05) (18) (0.625)
19 GW-3 Guaran Li-C8/IB/MaH/MVE Sodium -- 450 mAh/g 68.7 (0.56)
(0.62) Hypophosphite Graphite/SiO.sub.x (0.05) (18) 20 Aqu D-5284
Carboxymethyl Cellulose Styrene Butadiene -- -- 450 mAh/g 57.6
(com- (0.41) Latex Graphite/SiO.sub.x parative) (0.61) (41.4) 21
BVH8 Carboxymethyl cellulose Aqu D-5592 Sodium -- 450 mAh/g 56.9
(0.67) Polyacrylic Acid Hypophosphite Graphite/SiO.sub.x (0.22)
(0.19) (40.68) 22 BVH8 Carboxymethyl cellulose Aqu D-5592 Sodium --
450 mAh/g 59.6 (0.84) Polyacrylic Acid Hypophosphite
Graphite/SiO.sub.x (0.28) (0.028) (37.7) 23 WG-18 Carboxymethyl
Hydroxypropyl Lithiated Aqu D- Sodium -- 450 mAh/g 66.0 Guaran 5592
Polyacrylic Hypophosphite Graphite/SiO.sub.x (0.62) Acid (0.21)
(33) (0.21) 24 WG-18 Carboxymethyl Hydroxypropyl Lithiated Gantrez
.TM. Sodium -- 450 mAh/g 72.0 Guaran 139 Hypophosphite
Graphite/SiO.sub.x (0.62) (0.17) (0.19) (27.3) 25 WG-18
Carboxymethyl Hydroxypropyl Lithiated Aqu D- Sodium -- 450 mAh/g
62.9 Guaran 5592 Polyacrylic Hypophosphite Graphite/SiO.sub.x
(0.68) acid (0.19) (36.2) (0.226) 26 Aqu D-5284 Carboxymethyl
Cellulose Lithiated PAA -- -- 450 mAh/g 48.3 (com- (0.93) (MW =
.450 MM) Graphite/SiO.sub.x parative) (0.31) (50.5) 27 Aqu D-5284
Carboxymethyl Cellulose Lithiated PAA Sodium -- 450 mAh/g 47.2
(0.96) (MW = .450 MM) Hypophosphite Graphite/SiO.sub.x (0.32)
(0.05) (51.5) 28 Aqu D-5284 Carboxymethyl Cellulose Lithiated PAA
Sodium -- 450 mAh/g 54.1 (0.83) (MW = 4 MM) Hypophosphite
Graphite/SiO.sub.x (0.28 ) (0.048) (44.8) 29 Aqu D-5284
Carboxymethyl Cellulose Lithiated PAA Sodium -- 450 mAh/g 58.2
(0.9) (MW = 1.25 MM) Hypophosphite Graphite/SiO.sub.x (0.3) (0.048)
(48.4) 30 Aqu D-5284 Carboxymethyl Cellulose/ Lithiated Aqu D- --
-- 450 mAh/g 58.2 (com- Ambergum .TM. Carboxymethyl Cellulose 5592
Polyacrylic Graphite/SiO.sub.x parative) (2/1) acid (40.8) (0.41)
(0.61) 31 Lithiated Aqu D-5284 Carboxymethyl Lithiated PAA --
Bisphenol A 450 mAh/g 50.9 Cellulose (MW = 1.25 MM) diepoxy
Graphite/SiO.sub.x (0.86) (0.29) (0.048) (48.8) 32 Lithiated Aqu
D-5284 Carboxymethyl Lithiated PAA -- Bisphenol A 450 mAh/g 51.1
Cellulose (MW = 1.25 MM) diepoxy Graphite/SiO.sub.x (0.8) (0.27)
(0.12) (49.95) 33 Lithiated Aqu D-5284 Carboxymethyl Lithiated PAA
-- Bisphenol A 450 mAh/g 51.9 Cellulose (MW =1.25 MM) diepoxy
Graphite/SiO.sub.x (0.61) (0.21) (0.354) (46.8) 34 Lithiated Aqu
D-5284 Carboxymethyl Lithiated PAA -- Bisphenol A 450 mAh/g 51.5
Cellulose (MW = 1.25 MM) diepoxy Graphite/SiO.sub.x (0.44) (0.15)
(0.6) (47.3) 35 BVH8 Carboxymethyl Cellulose Aqu D-5592 Sodium --
450 mAh/g 56.9 (0.75) Polyacrylic acid Hypophosphite
Graphite/SiO.sub.x (0.25) (0.19) (42) 36 BVH8 Carboxymethyl
Cellulose Aqu D-5592 Sodium -- 450 mAh/g 63.2 (0.65) Polyacrylic
Acid Hypophosphite Graphite/SiO.sub.x (0.22) (0.19) (35.9) 37 Aqu
D-5284 Aqu D-5592 Sodium -- 450 mAh/g 67.2 Carboxymethyl Cellulose
Polyacrylic acid Hypophosphite Graphite/SiO.sub.x (0.58) (0.2)
(0.19) (32) 38 Aqu D-5283 Carboxymethyl Cellulose Aqu D-5592 Sodium
-- 450 mAh/g 72.1 (0.51) (0.16) Hypophosphite Graphite/SiO.sub.x
(0.19) (27.2) 39 Aqu D-5283 Carboxymethyl Cellulose Lithiated
Gantrez .TM. Sodium -- 450 mAh/g 66.8 (0.6) 139 Hypophosphite
Graphite/SiO.sub.x (0.19) (0.19) (32.4) 40 Aqu D-5284 Carboxymethyl
Cellulose 30% Sodium -- 450 mAh/g 66.1 (0.6) C8/IB/MaH/MVE
Hypophosphite Graphite/SiO.sub.x (0.2) (0.19) (33.1) 41 Aqu D-5284
Carboxymethyl Cellulose 30% C8/Gantrez .TM. Sodium -- 450 mAh/g
65.6 (0.61) 139 Hypophosphite Graphite/SiO.sub.x (0.2) (0.19)
(33.6) 42 Aqu D-5284 Carboxymethyl Cellulose 25% Jeffamin/ Sodium
-- 450 mAh/g 66.7 (0.61) Gantrez .TM. 169 Hypophosphite
Graphite/SiO.sub.x (0.2) (0.19) (32.5) 43 Aqu D-5284 Carboxymethyl
Cellulose Lithiated Gantrez .TM. Sodium -- 450 mAh/g 64.5 (0.61)
139 Hypophosphite Graphite/SiO.sub.x (0.2) (0.19) (34.7) 44 Aqu
D-5283 Carboxymethyl Cellulose Aqu D-5592 Sodium -- 450 mAh/g 68.4
(0.45) Polyacrylic acid Hypophosphite Graphite/SiO.sub.x (0.15)
(0.19) (31) 45 Aqu D-5283 Carboxymethyl Cellulose Lithium Gantrez
.TM. Sodium -- 450 mAh/g 65.1 (0.5) 139 Hypophosphite
Graphite/SiO.sub.x (0.16) (0.19) (34.2) 46 Aqu D-5284 Carboxymethyl
Cellulose Aqu D-5592 Sodium -- 450 mAh/g 67.2 (0.59) Polyacrylic
acid Hypophosphite Graphite/SiO.sub.x (0.195) (0.19) (32) 47 BVH8
Carboxymethyl Cellulose Aqu D-5592 Sodium -- 350 mAh/g 63.2 (0.66)
Polyacrylic acid Hypophosphite Graphite (0.22) (0.19) (35.9) 48 Aqu
D-5284 Carboxymethyl Cellulose Aqu D-5592 Sodium -- 350 mAh/g 67.2
(0.59) Polyacrylic acid Hypophosphite Graphite (0.19) (0.19) (32)
49 Aqu D-5284 Carboxymethyl Cellulose Lithium Gantrez .TM. Sodium
-- 350 mAh/g 64.5 (0.48) 139 Hypophosphite Graphite (0.15) (0.19)
(34.7) 50 BVH8 Carboxymethyl Cellulose JSR2001 SBR Latex -- -- 600
mAh/g 73.3 (com- (0.64) (0.96) Graphite/SiO.sub.x/ parative)
Conductive Carbon (25.13) 51 BVH8 Carboxymethyl Cellulose Aqu
D-5592 Sodium -- 600 mAh/g 74.6 (1.14) Polyacrylic acid
Hypophosphite Graphite/SiO.sub.x/ (0.38) (0.04) Conductive Carbon
(23.86) 52 BVH8 Carboxymethyl Cellulose Aqu D-5592 -- Bisphenol A
600 mAh/g 73.5 (1.184) Polyacrylic acid diepoxy Graphite/SiO.sub.x
(0.395) (0.158) (24.76) 53 WG-18 Carboxymethyl Hydroxypropyl --
Sodium -- 600 mAh/g 80.0 Guaran Hypophosphite Graphite/SiO.sub.x/
(1.2) (0.03) Conductive carbon (18.82) 54 WG-18 Carboxymethyl
Hydroxypropyl Aqu D-5592 Bisphenol A 600 mAh/g 63.6 Guaran
Polyacrylic Acid diepoxy Graphite/SiO.sub.x/ (1.09) (1.09) (0.22)
Conductive Carbon (34.06) 55 Lithium Gantrez .TM. 139 -- Sodium --
600 mAh/g 69.2 (1.85) Hypophosphite Graphite/SiO.sub.x/ (0.04)
Conductive Carbon (28.96) 56 BVH8 Carboxymethyl Cellulose Aqu
D-5592 Sodium -- 600 mAh/g 70.3 (0.856) Polyacrylic acid
Hypophosphite Si-Graphene/ (0.285) (0.05) Conductive Carbon (28.5)
57 BVH8 Carboxymethyl Cellulose Aqu D-5592 Sodium -- 600 mAh/g 75
(1.13) Polyacrylic acid Hypophosphite Si-Graphene/ (0.376) (0.08)
Conductive Carbon (23.5) 58 BVH8 Carboxymethyl Cellulose JSR2001
SBR Latex -- -- 600 mAh/g 73.8 (com- (0.63) (0.94) Si-Graphene/
parative) Conductive Carbon (24.6) 59 BVH8 Carboxymethyl Cellulose
Aqu D-5592 -- Bisphenol A 600 mAh/g 74.1 (1.16) Polyacrylic Acid
diepoxy Si-Graphene/ (0.387) (0.32) Conductive Carbon (24.1) 60
BVH8 Carboxymethyl Cellulose JSR 2001 SBR Latex -- -- 450 mAh/g
53.8 (com- (0.45) (0.54) Graphite/SiO.sub.x parative) (45.3) 61
BVH8 Carboxymethyl Cellulose Aqu D-5592 -- -- 450 mAh/g 59.0 (com-
(0.5) Polyacrylic acid Graphite/SiO.sub.x parative) (0.4) (40.1) 62
BVH8 Carboxymethyl Cellulose Aqu D-5592 0.19 -- 450 mAh/g 56.8
(0.77) Polyacrylic acid Graphite/SiO.sub.x (0.25) (42) 63 WG-18
Carboxymethyl hydroxypropyl -- -- -- 450 mAh/g 70 guaran
Graphite/SiO.sub.x (0.73) (29.3) 64 BVH8 Carboxymethyl Cellulose
Aqu D-5592 2- Bisphenol A 600 mAh/g 75.0 (1.12) Polyacrylic acid
Methylimidazole diepoxy Si-Graphene/ (0.37) (0.944) (0.126)
Conductive Carbon
(22.4) 65 BVH8 Carboxymethyl Cellulose Aqu D-5592 Carbodilite --
600 mAh/g 75.0 (1.305) Polyacrylic acid (0.09) Si-Graphene/ (0.435)
Conductive Carbon (23.2) 66 Carboxymethyl hydroxypropyl guaran --
2- Bisphenol A 450 mAh/g 58.0 (0.722) Methylimidazole diepoxy
Graphite/SiO.sub.x (0.014) (0.041) (41.2) 67 BVH8 Carboxymethyl
Cellulose Aqu D-5592 Sodium -- 410 mAh/g 59.4 (0.792) Polyacrylic
acid Hypophosphite SiO.sub.x-C Composite (0.198) (0.026) (39.6) 68
BVH8 Carboxymethyl Cellulose Aqu D-5592 C -- 421 mAh/g 59.4 (0.792)
Polyacrylic acid (0.026) Si-C Composite (0.198) (39.6) 69 BVH8
Carboxymethyl Cellulose Aqu D-5592 sodium -- 450 mAh/g 57.0 (0.694)
Polyacrylic acid/ hypophosphite Graphite/SiO.sub.x Citric acid
(0.02) (42.1) (0.208/0.023) 70 BVH8 Carboxymethyl Cellulose Aqu
D-5592 2- Bisphenol A 450 mAh/g 57.0 (0.670) Polyacrylic acid/
Methylimidazole diepoxy Graphite/SiO.sub.x Jaypol 5100 (0.084)
(0.014) (42.1) (0.112/0.112) Ingredients listed in Table 1: (1)
Carboxymethyl Guaran: Carboxymethyl substituted guaran commercially
available as GW-45LF from BJ Services (Houston, TX) having a
carboxymethyl degree of substitution of about 0.18 . (2) Aqu D-5284
Carboxymethyl cellulose: Aqualon .TM. Aqu D-5284, a commercially
available carboxymethyl cellulose available from Ashland, Inc.
(Wilmington, DE) with a degree of substitution from 0.8-0.95 and a
Brookfield .RTM. viscosity of 2,500-4,500 cps for a 1% solution at
30 rpm with spindle 4. (3) Ambergum .TM.: A commercially available
carboxymethyl cellulose available from Ashland, Inc. (Wilmington,
DE) with a degree of substitution from 0.8-0.95 and a Brookfield
.RTM. viscosity of 300-400 cps for a 1% solution at 30 rpm with
spindle 4. (4) Aqu D-5592: a commercially available polyacrylic
acid from Ashland, Inc. (Wilmington, DE). (5) WG-18 Carboxymethyl
hydroxypropyl guaran: CMHP Guaran commercially available as WG-18
from Halliburton Energy Services having a carboxymethyl degree of
substitution of about 0.14 and a hydroxypropyl degree of
substitution of about 0.3. (6) Kelset .RTM. NF Alginate is
available from FMC Biopolymer (Philadelphia, PA). (7) Xanthan Gum:
Rhodopol .RTM. 23, a commercially available xanthan gum product
available from Solvay, Rhodia (La Defense, France) (8) Kelcosol
.RTM. Alginate is available from FMC Biopolymer (Philadelphia, PA).
(9) Manasol .RTM. HV Alginate is available from FMC Biopolymer
(Philadelphia, PA). (10) Lithiated Alginate is Protacid .RTM.
F120NM available from FMC Biopolymer (Philadelphia, PA). (11)
Guaran: Unsubstituted guaran commercially available as GW-3LDF from
Baker Hughes Inc. (Houston, TX). (12) Styrene Butadiene Latex: JSR
.RTM. TR2001, commercially available styrene butadiene latex from
JSR Corporation, Tokyo Japan. (13) BVH8C Carboxymethyl cellulose:
Bondwell .TM. carboxymethyl cellulose available from Ashland, Inc.
(Wilmington, DE) with a degree of substitution from 0.8 to 0.95 and
a Brookfield .RTM. viscosity of 800-1,200 cps for a 1% solution at
30 rpm with spindle 4. (14) 30% C8/IB/MaH/MVE is a 30 mol %
octylamine modified copolymer of isobutylene, maleic anhydride, and
methyl vinyl ether. (15) Li-C8/IB/MaH/MVE is lithium salt of a 30
mol % octylamine modified copolymer of isobutylene, maleic
anhydride, and methyl vinyl ether. (16) Lithiated Gantrez .TM. 139
is a lithium salt of a copolymer of maleic anhydride and methyl
vinyl ether. Gantrez .TM. AN 139 is commercially available from
Ashland, Inc. (Wilmington, DE). (18) 30% C8/Gantrez .TM. 139 is a
30 mol % octylamine modified copolymer of maleic anhydride and
methyl vinyl ether, wherein the copolymer of maleic anhydride and
methyl vinyl ether is commercially available as Gantrez .TM. AN 139
from Ashland, Inc. (Wilmington, DE). (19) Polyacrylic acids having,
as specified in the table, molecular weights of 450,000, 1,250,000,
and 4,000,000 are commercially available polyacrylic acids from
Sigma Aldrich (St. Louis, MO). (20) 25% Jeffamin .RTM. Gantrez .TM.
169 is a polyetheramine modified copolymer of maleic anhydride and
methyl vinyl ether, wherein the polyetheramine is commercially
available as Jeffamine .RTM. from the Huntsman Corporation (Salt
Lake City, UT) and wherein the copolymer of maleic anhydride and
methyl vinyl ether is commercially available as Gantrez .TM. AN 169
from Ashland Inc. (Wilmington, DE). (21) Aqu D-5283 Carboxymethyl
cellulose: Aqualon .TM. Aqu D-5283, a commercially available
carboxymethyl cellulose available from Ashland, Inc. (Wilmington,
DE) having a degree of substitution of about 0.65-0.9 and a
Brookfield .RTM. viscosity of 6,200-9,000 cps for a 1% solution at
30 rpm with spindle 4. (22) Bisphenol A diepoxy is a di-epoxy water
dispersion commercially available as EPI-REZ .RTM. 6520-WH-53
available from Momentive Specialty Chemicals (Columbus, OH).
Slurry Stability Measurements
[0084] Slurry stability was measured for samples 1-70 of Table 1 by
placing the slurries in capped cylindrical glass bottles, which
were then stored at room temperature and periodically observed.
Specifically, 30 g of each slurry sample was placed in 50 mL glass
bottles after which they were observed each day for around 7 days.
The unstable slurry samples separated such that the water or low
viscosity solution formed a top layer and the graphite, graphite
and silicon oxide, and/or the silicon-graphene and conductive
carbon solution formed a bottom layer in the glass bottles. The
slurries were determined to be stable if they stayed in solution
for more than 24 hours, more preferably more than 5 days.
[0085] Additionally, some of the samples, as indicated in Table 2
below, had their viscosities measured two or more days after the
initial mixing, whereby a large increase or decrease in the slurry
viscosity indicated possible instability of the composition.
Rheology Measurements
[0086] Viscosities of the experimental slurry compositions were
measured with a Brookfield.RTM. viscometer from Brookfield
Engineering Laboratories, Inc. (Middleboro, Mass.) at 3 rpm and 30
rpm with spindle 4. As indicated in Table 2, the rheology values
for some samples were measured (1) in a 17 mL vial immediately
after mixing, and (2) a set time 24 hours or later after the
initial formation of the slurry.
TABLE-US-00002 TABLE 2 Viscosity in 17 mL Vial Viscosity After Time
Period Stability Sample # (3 RPM/30 RPM)(CPs) (3 RPM/30 RPM) (CPs)
(days) 1 (comparative) 24595/7158 After 48 hours: 27994/7458 >5
2 (comparative) 14597/7538 After 48 hours: 22195/8358 >5 3
(comparative) 22395/5779 After 24 hours: 25595/6679 >1 4
(comparative) 17996/8018 After 24 hours: 20396/7478 >1 5
(comparative) 34193/8478 After 5 days: 31393/8058 >5 6
(comparative) 21795/6259 After 5 days: 20996/6299 >5 7
(comparative) 69385/10938 After 5 days: 98279/14957 >3 8
(comparative) 11997/5679 After 5 days: 35392/8378 >3 9
(comparative) 23195/4439 After 5 days: 28994/4579 >5 10
(comparative) 17996/4679 After 5 days: 16197/4319 >5 11
(comparative) 19396/7658 After 5 days:: 44790/12217 <3 12
(comparative) 15997/7158 After 5 days: 9998/5059 >3 13
(comparative) 12797/2659 Separated overnight Unstable 14
(comparative) 5599/5659 After 5 days: 5700/6100 >5 15
(comparative) 25595/6619 Separated overnight Unstable 16
(comparative) 39392/8038 After 5 days: 36792/9318 >3 17
39392/8038 -- -- 18 30593/6339 -- -- 19 28394/7638 -- -- 20
(comparative) 11000/63000 After 5 days: 12000/6420 >5 21
30793/10918 -- 3 22 65989/out of range -- 3 23 25195/4499
20396/3879 2 24 37392/8878 35192/8578 2 25 8798/6879 separated 1 26
(comparative) 1400/2529 2799/3119 (After 2days) 2 27 2999/4379
6999/5819 (After 2days) 2 28 21395/7618 20797/8098 (After 3 days) 5
29 12797/7538 13997/8078 (After 2 days) 5 30 (comparative)
17996/8018 20396/7478 (After 2 days) 5 31 9198/5979 8398/5599
(After 2 days) 2 32 11598/6839 10198/6019 (After 2 days) 5 33
10998/5739 8798/4719 (After 2 days) 5 34 12797/4499 10998/4259
(After 2 days) 5 35 8398/6499 18396/8098 (After 3 days) 5 36
15997/9878 20786/7878 (After 3 days) 5 37 24995/8598 28394/8438
(After 3 days) 5 38 38994/7058 71985/9558 (After 3 days) 3 39
33793/9318 75384/11817 (After 3 days) 3 40 10398/5819 9998/4679
(After 4 days) 4 41 12397/6499 10398/5399 (After 4 days) 5 42
14797/9218 19396/7098 (After 3 days) 5 43 18996/7978 18196/7378
(After 2 days) 5 44 32193/7598 61387/9658 (After 2 days) 5 45
25395/9678 49589/8958 (After 2 days) 5 46 24995/8598 28394/8438
(After 3 days) 5 47 16197/7978 20796/8998 (After 2 days) 5 48
28994/9698 32193/9898 (After 2 days) 5 49 17996/8896 18796/7858
(After 2 days) 5 50 (comparative) 1400/320 1200/350 (After 2 days)
5 51 27394/10918 24395/8618 (After 2 days) 5 52 46790/5079
43791/3597 (After 2 days) 5 53 70985/7356 60187/5857 (After 2 days)
5 54 68985/11198 63386/11458 (After 1 day) 5 55 5999/1840 7598/1780
(After 1 day) 5 56 27994/8058 27194/7758 5 57 38992/11837
33793/10298 5 58 (comparative) 6199/2759 -- 5 59 53389/15857 -- 5
60 (comparative) 7798/6119 -- 3 61 (comparative) 18796/7585 -- 6 62
10398/6399 7998/5459 2 63 (comparative) 34193/8478 After 5 days:
31393/8058 >5 64 29594/10598 22995/8158 3 65 47390/15697
22995/8678 5 66 6039/2230 -- 1 67 22795/8678 31193/8178 >3 68
21795/7478 26794/7278 >3 69 8398/6039 8798/6259 2 70 7998/5059
9598/4899 6
Adhesion Measurements
[0087] Adhesion measurements were obtained by performing a 90
degree peel test on electrodes formed by coating and drying the
slurry compositions on copper current collectors.
[0088] The electrodes were formed by coating the slurry
compositions on copper current collectors having a thickness of
between approximately 12.45 and 15 .mu.m and then using a tape
caster (doctor blade) to lessen the slurry layer to a wet thickness
of approximately 30 .mu.m. The slurry compositions not containing
any esterification catalyst or epoxy resin were heated to only
about 100.degree. C. for about 1 hour, while the samples containing
either esterification catalyst and/or epoxy resin were heated for
about 0.5 hours at about 100.degree. C. and additionally heated at
about 150.degree. C. for about 2 hours to evaporate the water from
the slurry composition to form a film on the copper current
collector. The current collector coated with the dry film was then
placed in a roll press for approximately one minute until the film
had a thickness in a range of from about 17 .mu.m to about 55
.mu.m, forming an anode electrode.
[0089] The electrodes were subjected to a 90 degree peel test using
a peel test fixture from Instron.RTM. (Norwood, Mass.), wherein the
electrodes were tested both after the initial hour of heating at
100.degree. C. and, for the applicable samples, after the second
hour of heating at 150.degree. C., as indicated in Table 3. The
individual electrode samples were mounted on a stainless steel
plate with 3M.RTM. double sided scotch tape from 3M Corporation
(St. Paul, Minn.) after which the film, which was also stuck to the
scotch tape, was peeled off at a rate of 1 foot/min. by the
Instron.RTM. Instrument during which the Instron.RTM. Instrument
measured the force necessary to peel the film off the current
collector.
[0090] Table 3 demonstrates that the adhesion of films formed from
slurries comprising carboxymethyl-modified and carboxymethyl
hydroxypropyl-modified guaran is as good as, if not better than,
the adhesion of films formed from slurries containing traditional
binders like, for example, carboxymethyl cellulose and styrene
butadiene latex, and/or alternative components. An adhesion above
0.3 gf/mm is generally considered to be acceptable, while an
adhesion value above 0.5 gf/mm is considered to be good.
TABLE-US-00003 TABLE 3 Adhesion (gf/mm) Sample # Dried at
100.degree. C. Dried at 150.degree. C. 1 (comparative) 3.55 -- 2
(comparative) 1.65 -- 3 (comparative) 1.87 -- 4 (comparative) 0.30
-- 5 (comparative) 3.58 -- 6 (comparative) 2.22 -- 7 (comparative)
3.75 -- 8 (comparative) 3.00 -- 9 (comparative) 2.68 -- 10
(comparative) 1.61 -- 11 (comparative) 2.94 -- 12 (comparative)
2.59 -- 13 (comparative) -- -- 14 (comparative) 0.27 -- 15
(comparative) 0.23 -- 16 (comparative) 1.26 -- 17 -- 1.38 18 --
1.96 19 -- 1.07 20 (comparative) 0.41 -- 21 -- 0.27 22 -- 0.45 23
-- -- 24 -- -- 25 -- -- 26 (comparative) 0.091 -- 27 -- 0.125 28 --
0.18 29 -- 0.141 30 (comparative) 0.296 -- 31 -- 0.325 32 -- 0.2 33
-- 0.243 34 -- 0.235 35 -- 0.8 36 -- 0.89 37 -- 1.7 38 -- -- 39 --
-- 40 -- 1.18 41 -- 0.85 42 -- 0.44 43 -- 0.46 44 -- -- 45 -- -- 46
-- 1.7 47 -- 0.54 48 -- 1.49 49 -- 0.46 50 (comparative) 8.46 -- 51
-- 4.21 52 -- 4.1 53 -- 1.07 54 -- 2.32 55 -- 1.12 56 -- 1.75+ 57
-- 1.75+ 58 (comparative) -- -- 59 -- 1.75+ 60 -- -- 61 0.41 -- 62
-- 0.98 63 3.8 -- 64 1.75+ 65 0.95 66 0.88 67 0.42 68 0.37 69 0.44
70 0.32
Electrochemical Tests
[0091] Half coin cells having a 20 mm diameter and a 3.2 mm height
(i.e., "CR-2023" half coin cells) were produced using the anodes
described above in combination with lithium metal disc cathodes, a
polyolefin separator, and an electrolyte comprising a mixture of
organic solvents and using lithium hexafluorophosphate (LiPF.sub.6)
as the lithium salt. The half coin cells were subjected to cyclic
and rate capability tests as various rates, as well as a test to
determine impedance of the half coin cells.
Impedance
[0092] Impedance of the above-described 2032 half coin cells was
measured using a Solartron.RTM. 1260 from Soalrtron Analytical
(Leicester, UK).
Coulombic Efficiency, Capacity, and Capacity Retention
[0093] Coulombic efficiency, capacity, and capacity retention of
the above-described 2032 half coin cells were measured using a
Maccor Model 4000 BCT system. Additionally, two different test
procedures were used for the half coin cells comprising electrode
active materials with an initial capacity of 450 mAh/g and 600
mAh/g.
[0094] For half coin cells with an initial capacity of 450 mAh/g,
electrochemical properties were measured by: (1) conditioning the
coin cells for 3 cycles at c/20 with a cutoff voltage between 0.005
and 1.5 V; (2) measuring the cycling life with constant charge and
discharge at c/3 with a cutoff voltage of 0.005 to 1.0 V; and (3)
varying the c-rate for 5 cycles at c/20-CC, 5 cycles at c/10-CCCV,
5 cycles at c/5-CCCV, 5 cycles at c/2-CCCV, 5 cycles at 1 c-CCCV,
with a CV cutoff current at C/20.
[0095] For half coin cells with an initial capacity of 600 mAh/g,
electrochemical properties were measured by: (1) conditioning the
coin cells for 4 cycles at c/20 with a cutoff voltage between 0.005
and 1.5 V; (2) measuring the cycling life with constant charge and
discharge at c/3 with a cutoff voltage of 0.005 to 1.0 V; and (3)
varying the c-rate for 5 cycles at c/20-CC, 5 cycles at c/10-CCCV,
5 cycles at c/5-CCCV, 5 cycles at c/2-CCCV, 5 cycles at 1 c-CCCV,
with a CV cutoff current at C/20.
[0096] Table 4 presents the electrochemical data for the half coin
cells made from the compositions in Table 1.
TABLE-US-00004 TABLE 4 Average Impedance Initial Second Capacity
Loading Ref Coulombic Coulombic 100 cycles Capacity Sample #
(mg/cc) (ohms) Efficiency % Efficiency % (mAh/g) Retention % 1
(comparative) -- 119 84.9 94.8 318 71 2 (comparative) -- 114 87.5
96.3 300 67 3 (comparative) -- 135 87.9 93.7 308 68 4 (comparative)
-- 131 89.2 97.5 292 65 5 (comparative) -- 132 84.6 95.0 306 68 6
(comparative) -- 141 85.1 95.7 313 70 7 (comparative) -- -- -- --
-- -- 8 (comparative) -- -- -- -- -- -- 9 (comparative) -- 128 83.5
95.4 306 92 10 (comparative) -- 143 85.3 95.3 280 89 11
(comparative) -- 186 82.5 95.9 220 49 12 (comparative) -- 178 85.8
95.7 309 69 13 (comparative) -- -- -- -- -- -- 14 (comparative) --
-- -- -- -- -- 15 (comparative) -- -- -- -- -- -- 16 (comparative)
-- 97 78.9 93.9 270 82 17 -- 92 82.7 94.8 286 64 18 -- 93 80.5 94.6
233 52 19 -- 99 81.0 94.3 266 59 20 (comparative) -- 70 84.8 96.9
304 86 21 0.9 120 86.6 94.1 -- -- 22 1.5 210 87.6 91.7 -- -- 23 0.9
133 80.8 95.0 309 76.4 24 1.2 215 82.0 94.1 315 76.3 25 1.9 112
82.7 94.6 -- -- 26 (comparative) -- -- -- -- -- -- 27 -- -- -- --
-- -- 28 2.4 170 84.7 95.7 -- -- 29 2.6 166 87.4 96.4 -- -- 30
(comparative) 3.0 131 89.2 97.5 292 96.0 31 1.9 106 84.7 95.8 -- --
32 1.8 272 85.1 95.6 -- -- 33 -- -- -- -- -- -- 34 -- -- -- -- --
-- 35 2.6 118 86.9 98.7 273 86.3 36 2.7 123 83.2 95.3 231 85.5 37
2.2 203 84.1 95.4 224 75.3 38 -- -- -- -- -- -- 39 -- -- -- -- --
-- 40 2.5 55 81.7 94.7 240 84.3 41 2.5 82 82.7 94.9 290 93.5 42 2.4
96 80.6 94.6 -- -- 43 2.5 115 85.2 95.3 307 93.5 44 -- -- -- -- --
-- 45 -- -- -- -- -- -- 46 2.2 203 84.1 95.4 224 75.3 47 3.4 145
93.3 99.2 170 47.7 48 3.3 218 92.8 97.1 339 99.1 49 3.3 114 93.4%
98.7% 341 95.8% 50 (comparative) 1.2 515 81.5 96.2 -- -- 51 1.4 159
80.4 92.1 -- -- 52 1.4 172 80.2 91.9 -- -- 53 1.6 132 77.2 90.2 --
-- 54 1.5 39 78.6 90.3 -- -- 55 -- -- -- -- -- -- 56 0.7 125 86.2
97.0 373.4 64.5 57 0.4 127 85.1 97.1 442.5 77.1 58 (comparative)
1.2 89 85.4 95.3 287.3 63.3 59 1.0 97 85.5 96.1 328.1 72.4 60 -- 86
86.3 95.2 -- 66 61 -- 59 84.8 94.6 -- 86 62 -- 100 89.6 98.9 --
93.4 63 -- 132 84.6 94.6 -- 96.2 64 1.6 88 88.8 97.6 394.8 75.3 65
1.9 150 67.3 84..3 78.6 11.6 66 4.1 94 87.5 95.9 321.1 89.9 67 4.2
52 90.2 98.3 369.0 88.2 68 4.0 65 87.5 96.9 329.1 79.3 69 2.2 221
87.3 97.3 334.8 90.3 70 2.1 232 84.7 95.4 105.4 33.1
[0097] Additionally, the capacity retention at 300 cycles was also
measured for samples 60-63, wherein a capacity retention for sample
60 was not measured, sample 61 had a capacity retention of 84.8,
sample 62 had a capacity retention of 92.6, and sample 63 had a
capacity retention as measured only at 200 cycles. Additionally,
samples 60, 61, 62, 63 were found to have lifetimes of about 180,
more than 300, more than 400, and about 200, respectively.
[0098] From the above description, it is clear that the inventive
concept(s) disclosed herein is well adapted to carry out the object
and to attain the advantages mentioned herein as well as those
inherent in the inventive concept(s) disclosed herein. While
exemplary embodiments of the inventive concept(s) disclosed herein
have been described for purposes of this disclosure, it will be
understood that numerous changes may be made which will readily
suggest themselves to those skilled in the art and which are
accomplished without departing from the scope of inventive
concept(s) disclosed herein and defined by the appended claims.
* * * * *