ELECTRODES OF LI-ION BATTERIES
WITH IMPROVED CONDUCTIVITY
5
FIELD OF THE INVENTION
The present invention relates generally to the field of electrical energy
storage in the lithium storage batteries of Li-ion type. More specifically, the
invention relates to a Li-ion battery electrode material, to its method of
10 preparation and to its use in a Li-ion battery. Another subject matter of the
invention is the Li-ion batteries manufactured by incorporating this electrode
material.
TECHNICAL BACKGROUND
15 An elementary cell of a Li-ion storage battery or lithium battery comprises
an anode (at discharge), generally made of lithium metal or based on carbon,
and a cathode (likewise at discharge), generally made of a lithium insertion
compound of metal oxide type, such as LiMn204, LiCo02 or LiNi02, between
which is inserted an electrolyte which conducts lithium ions.
2 0 A cathode or an anode generally comprises at least one current collector
on which is deposited a composite material which consists of: one or more
"active" materials, active because they exhibit an electrochemical activity with
respect to lithium, one or more polymers which act as binder and which are
generally functionalized or nonfunctionalized fluoropolymers, such as
25 polyvinylidene fluoride, or aqueous-based polymers of carboxymethylcellulose
type or styrenelbutadiene latexes, plus one or more electron-conducting
additives which are generally allotropic forms of carbon.
The conventional active materials at the negative electrode are generally
lithium metal, graphite, siliconlcarbon composites, silicon, fluorographites of CF,
30 type with x between 0 and 1, and titanates of LiTi5Oq2ty pe.
The conventional active materials at the positive electrode are generally
of the LiM02 type, of the LiMP04 type, of the Li2MP03F type, of the Li2MSi04
type, where M is Co, Ni, Mn, Fe or a combination of these, of the LiMn204 type
or of the S8 type.
35 Recently, additives which make it possible to improve the permeability of
the electrolyte to the core of the electrode have been used. As a result of the
growing demand for high-energy batteries, that is to say batteries with higher
electric storage capacities, the thickness of the electrodes is increasing and
thus the permeability of the electrolyte is becoming important in the overall
resistance of the battery. With the aim of improving this permeability, the
document W02005/011044 describes the addition of "inorganic" fillers of metal
5 oxides, such as A12O3 and Si02. These inorganic fillers are added during the
conventional process for the manufacture of electrodes. This conventional
process consists in mixing the different constituents in a solvent or a mixture of
solvents, such as, for example, N-methylpyrrolidone, acetone, water or ethylene
carbonate:
10 1. at least one conducting additive at a content ranging from 1 to 5% by
weight, preferably from 1.5 to 4% or 1 to 2.5% by weight, preferably from
1.5 to 2.2% by weight, with respect to the total weight of the composite
material;
2. a lithium oxide, phosphate, fluorophosphate or silicate as electrode
15 active material capable of reversibly forming an insertion compound with
lithium, having an electrochemical potential greater than 2V with respect
to the LilLi* pair;
3. a polymer binder.
The ink obtained is subsequently coated onto the current collector and
2 0 the solvent or solvents are evaporated by heating ranging from 30 to 200°C.
The failings of these inorganic fillers are that they decrease the amount
of active material in the electrode and thus the capacity of the battery but also
these fillers only make it possible to improve the macroscopic diffusion of the
electrolyte.
2 5 In point of fact, in the electrode, it is the charging resistance of the active
material/electrolyte interface which is limiting for the performance of the battery.
This resistance is a microscopic effect which cannot be improved by the
addition of macroscopic inorganic filler.
The applicant has discovered that the addition of a salt consisting of an
30 organic anion, chosen in order to have a favorable interaction at the surface of
the active material, makes it possible to increase the ionic conductivity of the
electrode.
Furthermore, an improvement in the cohesion and adhesion properties of
the electrode on metal by the specific choice of the polymer binder has been
35 looked for.
SUMMARY OF THE INVENTION
The invention relates to an electrode composition, characterized by the
simultaneous presence of a high-performance fluoropolymer binder capable of
ensuring good cohesion and adhesion properties at a low content in the
cathode and of a specific organic salt which improves the ionic conductivity of
5 the electrode.
The invention relates first to the use of organic salts as ionic conductivity
additives in the formulation of electrodes of Li-ion storage batteries, preferably
in the cathode formulation. These salts can also be used in the formulation of
electrodes of Na-ion batteries.
10 Another subject matter of the invention is the use of said formulation as
battery electrode.
The ion-conducting additive has to be capable of withstanding the
conditions of the process for the preparation of the electrodes described above.
For example, LiPF6, the lithium salt currently used in the majority of the
15 electrolytes, due to its temperature instability and instability toward nucleophilic
solvents, cannot be used as ionic conductivity additive.
The invention also relates to a Li-ion battery electrode composite
material, preferably a positive electrode material, comprising:
a) at least one electron-conducting additive at a content ranging from
1 to 5% by weight, preferably from 1.5 to 4% or from 1 to 2.5% by
weight, preferably from 1.5 to 2.2% by weight, with respect to the
total weight of the composite material;
b) a lithium oxide, phosphate, fluorophosphate or silicate as
electrode active material capable of reversibly forming an insertion
compound with lithium, having an electrochemical potential of
greater than 2V with respect to the LilLi' pair;
c) a polymer binder;
d) at least one organic salt of formula A and/or B,
In the formula (A), -Xi- independently represents the following groups or
atoms: -N=, -N--, -C(R)=, -C-(R)-, -0-, -S(=O)(R)= or -S(R)= and R represents a
group chosen from F, CN, NO2, S-CN, N=C=S, -OCnHmFp, -C,H,F, with n, m
and p integers. The compounds of formula (A) which are particularly preferred
5 are the imidazolates represented below and advantageously lithium
imidazolates:
where R represents F or -CnHmFp. These lithium salts are particularly
advantageous due to their insensitivity to water, which makes possible simplified
10 use in the process for the preparation of the electrode.
In the formula (B), Rf represents F, CF3, CHF2, CHZF, C2HF4. C2H2F4,
CzH3F2, C~FSC,3 F6, C3HzF5, C3H4F3, C4F9, C4H2F7. C4H4Fsr C5Fii. C3F50CF3,
C2F40CF3, CzH2F20CF3 or CF20CF3 and Z represents an electron-withdrawing
group chosen from F, CN, SOzRf, C02Rf or CORf
15 In the general formulae above, M' represents a lithium cation, a sod~um
cation, a quaternary ammonium or an imidazolium. Preferably, M' represents a
lithium cation or a sodium cation.
Preferably, the constituent (d) can vary between 0.01 and 10% and
advantageously from 0.05 to 5% by weight, with respect to the total weight of the
20 material.
The electron-conducting additive is preferably chosen from the different
allotropic forms of carbon or conducting organic polymers.
Characteristically, the polymer binder is chosen from fluoropolymer
binders of high molecular weight and/or which carry functional group(s) capable
25 of developing adhesion to a metal substrate and good cohesion of the material
making up the electrode.
According to one embodiment, said binder is a fluoropolymer of high
molecular weight, preferably a fluoropolymer of very high molecular weight. The
fluoropolymers are chosen from vinylidene fluoride and chlorotrifluoroethylene
30 copolymers, and poly(viny1idene fluoride).
Preference is given, among these, to poly(viny1idene fluoride) or PVDF
having a melt viscosity of greater than or equal to 2000 Pa.s at 232°C under
shearing of 100 s-'. The viscosity is measured at 232"C, at a shear gradient of
100 s-', using a capillary rheometer or a parallel-plate rheometer, according to
the standard ASTM 03825. The two methods give similar results.
The term "PVDF" employed here comprises vinylidene fluoride (VDF)
5 homopolymers or copolymers of VDF and of at least one other comonomer in
which the VDF represents at least 50 mol%. The comonomers which can be
polymerized with VDF are chosen from vinyl fluoride, trifluoroethylene,
chlorotrifluoroethylene (CTFE), 1,2-difluoroethylene, tetrafluoroethylene (TFE),
hexafluoropropylene (HFP), perfluoro(alkyl vinyl) ethers, such as
10 perfluoro(methy1 vinyl) ether (PMVE), perfluoro(ethy1 vinyl) ether (PEVE) or
perfluoro(propyl vinyl) ether (PPVE), perfluoro(l,3-dioxole), perfluoro(2,2-
dimethyl-I ,3-dioxole) (PDD), the product of formula
CF2=CFOCF2CF(CF3)0CF2CF2X in which X is SOzF, C02H, CH20H, CH20CN
or CHZOPO~Ht,h e product of formula CF2=CFOCF2CF2S02Ft,h e product of
15 formula F(CF2),CH20CF=CF2 in which n is I, 2, 3, 4 or 5, the product of formula
R1CH20CF=CF2 in which R1 is hydrogen or F(CF2), and z has the value 1, 2, 3
or 4, the product of formula R30CF=CH2 in which R3 is F(CF2), and z has the
value 1, 2, 3 or 4, or also perfluorobutylethylene (PFBE), fluorinated ethylene
propylene (FEP), 3,3,3-trifluoropropene, 2-trifluoromethyl-3,3,3-trifluoro-I-
20 propene, 2,3,3,3-tetrafluoropropene or HFO-1234yf, E-1,3,3,3-
tetrafluoropropene or HFO-1234zeE, Z-1,3,3,3-tetrafluoropropene or HFO-
1234zeZ, 1,1,2,3-tetrafluoropropene or HFO-1234yc, 1,2,3,3-tetrafluoropropene
or HFO-l234ye, 1 , I ,3,3-tetrafluoropropene or HFO-1234zc, and
chlorotetrafluoropropene or HCFO-1224.
According to one embodiment, the copolymer is a terpolymer.
According to another embodiment, said binder is a fluoropolymer carrying
functional group(s) capable of developing adhesion to a metal substrate and
good cohesion of the material making up the electrode. it can be a polymer
based on VDF (containing at least 50 mol% of VDF) additionally comprising
30 units carrying at least one of the following functional groups: carboxylic acid,
carboxylic acid anhydride, carboxylic acid esters, epoxy groups (such as
glycidyl), amide groups, alcohol groups, carbonyl groups, mercapto groups,
sulfide, oxazoline groups and phenol groups. The functional group is introduced
onto the fluoropolymer by a chemical reaction which can be grafting or a
35 copolymerization of the fluoropolymer with a compound carrying at least one of
said functional groups, according to techniques well known to a person skilled in
the art.
According to one embodiment, the carboxylic acid functional group is a
hydrophilic group of (meth)acrylic acid type chosen from acrylic acid,
methacrylic acid, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate and
hydroxyethylhexyl (meth)acrylate.
5 According to one embodiment, the units carrying the carboxylic acid
functional group additionally comprise a heteroatom chosen from oxygen,
sulfur, nitrogen and phosphorus.
When the fluoropolymer is functionalized, the content of functional
groups ensuring the adhesion of the binder to a metal is at least 0.05 mol% and
10 preferably at least 0.15 mol%.
The metal supports of the electrodes are generally made of aluminum for
the cathode and of copper for the anode.
PREPARATION OF THE ELECTRODE
15 Another subject matter of the present invention is a process for the
preparation of the electrode composite material described above, which
comprises:
i) at least a stage of preparation of a suspension involving:
- one or more organic salts of formula A andlor B;
2 0 - an electron-conducting additive;
- a polymer binder according to the invention;
- one or more volatile solvents;
- an electrode active material chosen from a lithium oxide, phosphate,
fluorophosphate or silicate, and
2 5 ii) a stage of preparation of a film starting from the suspension prepared
in (i).
The suspension can be obtained by dispersion and homogenization by
any mechanical means, for example using a rotor-stator or an anchor stirrer or
by ultrasound.
3 0 The suspension can be prepared from the polymer in the pure state or in
the form of a solution in one or more volatile solvent(s), from the organic salts in
the pure state or in the form of a suspension in one or more volatile solvent(s),
from the electron-conducting additive and from the active material in the pure
state, optionally after a stage of drying at a temperature of between 50 and
35 150°C.
Preferably, the volatile solvent(s) is or are chosen from an organic solvent
or water. Mention may in particular be made, as an organic solvent, of the
organic solvents N-methylpyrrolidone (NMP) or dimethyl sulfoxide (DMSO).
The suspension can be prepared in a single stage or in two or three
5 successive stages. When the suspension is prepared in two successive stages,
one embodiment consists in preparing, in the first stage, a dispersion containing
the solvent, the organic salt(s) and optionally all or part of the polymer binder,
using mechanical means, and then, in a second stage, in adding the other
constituents of the composite material to this first dispersion. The film is
10 subsequently obtained from the suspension on conclusion of the second stage.
When the suspension is prepared in three successive stages, one
embodiment consists in preparing, in the first stage, a dispersion containing the
organic salt(s) and optionally all or part of the polymer binder in a solvent, and
then, in the second stage, in adding the active material and removing the
15 solvent, in order to obtain a powder, and subsequently in adding solvent and the
remainder of the constituents of the composite material, in order to obtain a
suspension. The film is subsequently obtained from the suspension on
conclusion of the third stage.
The dissolution of the organic salts of formula A andlor B can be carried
2 0 out at temperatures ranging from 0 to 1 5O0C, preferably between 10 and 100°C.
In addition, a subject matter of the present invention is Li-ion batteries
incorporating said material.
Example 1: Process for the manufacture of a cathode and composition of a
25 cathode according to the invention
Stirring is carried out using a rotor-stator. 0.0197 g of LiTDl (formula
above) is placed in a flask. Dissolution is carried out with 7.08 g of NMP (Nmethylpyrrolidone)
and the solution is left stirring at 25°C for 10 min. 0.1974 g of
30 binder according to the invention (chosen from the binders defined below) is
added and the mixture is left stirring at 50°C for 30 min. 0.1982 g of Super P
carbon (~irncal') is subsequently added and the mixture is left stirring for 2 h,
Finally, 4.5567 g of LiMn204 and 2.52 g of NMP are added and the mixture is left
stirring for 3 h. The suspension is subsequently spread in the form of a film with
a thickness of 100 pm over a sheet of aluminum. The film is allowed to dry at
130°C for 5 h.
5 Fluorinated binders according to the invention:
l a - ~ ~ n aHrS' V SOO: PVDF homopolymer sold by Arkema France, with a melt
viscosity of greater than 4000 Pa.s at 232°C and 100 s-'
lo 2a - Kynar@ HSV500: PVDF homopolymer sold by Arkema France, with a melt
viscosity of 3000 Pa.s at 232°C and 100 s-'
3a - KynarflexB LBG: Copolymer of VDF and HFP sold by Arkema France, with a
melt viscosity of 3300 Pa.s at 232°C and 100 s-'
15
4a - Kureha@ 7200: PVDF homopolymer sold by Kureha, with a melt viscosity of
greater than 2700 Pas at 232°C and 100 s-'
5a - sole$ 5130: Functionalized PVDF sold by Solvay, with a melt viscosity of
20 greater than 2700 Pa.s at 232°C and 100 s-'
Example 2: Process for the manufacture of a cathode and composition of a
25 cathode accordinu to the invention
0
Stirring is carried out using a rotor-stator. 0.0183 g of LiFSl (formula
above) is placed in a flask. Dissolution is carried out with 6.56 g of NMP (Nmethylpyrrolidone)
and the solution is left stirring at 25°C for 10 min. 0.1831 g of
30 binder according to the invention (chosen from the binders defined below) is
added and the mixture is left stirring at 50°C for 30 min. 0.1838 g of Super P
carbon (~imcali~s )s ubsequently added and the mixture is left stirring for 2 h.
Finally, 4.2257 g of LiNiMnCo02 (proportions of Ni, Mn and Co: 1/1/1) and 2.34
g of NMP are added and the mixture is left stirring for 3 h. The suspension is
subsequently spread in the form of a film with a thickness of 100 pm over a
sheet of aluminum. The film is allowed to dry at 130°C for 4 h.
5
Fluorinated binders according to the invention:
l a - Kynarm HSVSOO: PVDF homopolymer sold by Arkema France, with a melt
viscosity of greater than 4000 Pa.s at 232°C and 100 s-'
10
2a - KynarB HSV500: PVDF homopolymer sold by Arkema France, with a melt
viscosity of 3000 Pa.s at 232°C and 100 s-'
3a - ~~narflexL'B G: Copolymer of VDF and HFP sold by Arkema France, with a
15 melt viscosity of 3300 Pas at 232°C and 100 s-'
4a - ~ u r e h7a2~00 : PVDF homopolymer sold by Kureha, with a melt viscosity of
greater than 2700 Pas at 232°C and 100 s-'
20 5a - ~ o l e p51 30: Functionalized PVDF sold by Solvay, with a melt viscosity of
greater than 2700 Pas at 232°C and 100 s-'
25 Example 3: Process for the manufacture of a cathode and composition of a
cathode accordinq to the invention
Stirring is carried out using a rotor-stator. 0.0203 g of LiTFSl (formula
above) is placed in a flask. Dissolution is carried out with 7.30 g of NMP (N-
30 methyipyrrolidone) and the solution is left stirring at 25°C for 10 min. 0.2038 g of
binder according to the invention (chosen from the binders defined below) is
added and the mixture is left stirring at 50°C for 30 min. 0.2046 g of Super P
carbon (Timcalm) is subsequently added and the mixture is left stirring for 2 h.
Finally, 4.7037 g of LiNiMnCo02 (proportions of Ni, Mn and Co: 51312) and 2.60
g of NMP are added and the mixture is left stirring for 3 h. The suspension is
subsequently spread in the form of a film with a thickness of 100 pm over a
5 sheet of aluminum. The film is allowed to dry at 130°C for 4 h.
Fluorinated binders according to the invention:
l a - Kynarm HSVSOO: PVDF homopolymer sold by Arkema France, with a melt
10 viscosity of greater than 4000 Pa.s at 232°C and I00 s-I
2a - Kynarm HSV500: PVDF homopolymer sold by Arkema France, with a melt
viscosity of 3000 Pa.s at 232°C and I00 s-'
15 3a - ~~narflexL'B G: Copolymer of VDF and HFP sold by Arkema France, with a
melt viscosity of 3300 Pa.s at 232°C and 100 s-'
4a - Kureha' 7200: PVDF homopolymer sold by Kureha, with a melt viscosity of
greater than 2700 Pa.s at 232°C and I00 s-I
2 0
5a - sole$ 5130: Functionalized PVDF sold by Solvay, with a melt viscosity of
greater than 2700 Pa.s at 232°C and 100 s-'
2 5
Example 4: Process for the manufacture of a cathode and composition of a
cathode accordinq to the invention
Stirring is carried out using a rotor-stator. 0.0201 g of LiFTFSl (formula
30 above) is placed in a flask. Dissolution is carried out with 7.23 g of NMP (Nmethylpyrrolidone)
and the solution is left stirring at 25°C for 10 min. 0.2016 g of
binder according to the invention (chosen from the binders defined below) is
added and the mixture is left stirring at 50°C for 30 min. 0.2025 g of Super P
carbon (~imcal') is subsequently added and the mixture is left stirring for 2 h.
Finally, 4.6547 g of LiCo02 and 2.57 g of NMP are added and the mixture is left
stirring for 3 h. The suspension is subsequently spread in the form of a film with
a thickness of 100 pm over a sheet of aluminum. The film is allowed to dry at
5 130°C for 4 h.
Fluorinated binders according to the invention:
l a - ~ ~ n a Hr S' VSOO: PVDF homopolymer sold by Arkema France, with a melt
10 viscosity of greater than 4000 Pa.s at 232°C and 100 s-'
2a - Kynarm HSV500: PVDF homopolymer sold by Arkema France, with a melt
viscosity of 3000 Pas at 232°C and 100 s-'
15 3a - Kynarflexa LBG: Copolymer of VDF and HFP sold by Arkema France, with a
melt viscosity of 3300 Pa.s at 232°C and 100 s-'
4a - Kureham 7200: PVDF homopolymer sold by Kureha, with a melt viscosity of
greater than 2700 Pa.s at 232°C and 100 dl
2 0
5a - Sole$ 5130: Functionalized PVDF sold by Solvay, with a melt viscosity of
greater than 2700 Pas at 232°C and 100 s-'
Example 5: Process for the manufacture of a cathode and composition of a
cathode accordinq to the invention
3 0 Stirring is carried out using a rotor-stator. 0.0182 g of LiPDl (formula
above) is placed in a flask. Dissolution is carried out with 6.53 g of NMP (Nmethylpyrrolidone)
and the solution is left stirring at 25°C for 10 min. 0.1821 g of
binder according to the invention (chosen from the binders defined below) is
added and the mixture is left stirring at 50°C for 30 min. 0.1829 g of Super P
carbon (~imcal') is subsequently added and the mixture is left stirring for 2 h.
Finally, 4.2045 g of LiFeP04 and 2.32 g of NMP are added and the mixture is left
stirring for 3 h. The suspension is subsequently spread in the form of a film with
5 a thickness of 100 pm over a sheet of aluminum. The film is allowed to dry at
130°C for 4 h.
Fluorinated binders according to the invention:
10 l a - Kynarm HSV9OO: PVDF homopolymer sold by Arkema France, with a melt
viscosity of greater than 4000 Pa.s at 232°C and 100 s-'
2a - KYnara HSV500: PVDF homopolymer sold by Arkema France, with a melt
viscosity of 3000 Pa.s at 232°C and 100 s-'
15
3a - Kynarflexa LBG: Copolymer of VDF and HFP sold by Arkema France, with a
melt viscosity of 3300 Pa.s at 232°C and lo0 s"
4a - Kureha' 7200: PVDF homopolymer sold by Kureha, with a melt viscosity of
20 greater than 2700 Pa.s at 232°C and 100 s-'
5a - sole$ 5130: Functionalized PVDF sold by Solvay, with a melt viscosity of
greater than 2700 Pa.s at 232°C and 100 s-'

CLAIM:
1. A battery electrode composite material, preferably a positive electrode
material, comprising:
a) at least one electron-conducting additive at a content ranging from
1 to 5%, preferably from 1.5 to 4% or from 1 to 2.5% by weight,
preferably from 1.5 to 2.2% by weight, with respect to the total
weight of the composite material;
b) a lithium oxide, phosphate, fluorophosphate or silicate as
electrode active material capable of reversibly forming an insertion
compound with lithium, having an electrochemical potential of
greater than 2V with respect to the LiILi' pair;
c) a fluorinated polymer binder;
d) at least one organic salt,
15 characterized in that said organic salt exhibits the formula A andlor the
formula B,
with -Xi- in the formula A independently representing the following groups
or atoms: -N=, -N--, -C(R)=, -C-(R)-, -0-, -S(=O)(R)= or -S(R)= with R
2 0 representing a group from the group consisting of F, CN, NO2, S-CN,
N=C=S, -OCnHmF,, -CnHmF, with n, m and p integers, Rf in the formula B
representing F, CF3, CHF2, CHZF, C2HF4, C2H2F4, C2H3F2, C2F5, C3F6,
C3HzF5, C3H4F3, C4F9, C4HzF7, C4H4F5, C5Fitr C3FsOCF3, C2F40CF3,
C2H2F20CF3 or CF20CF3 and Z representing an electron-withdrawing
2 5 group chosen from F, CN, SOzRf, C02Rf or CORr and M' representing a
lithium, sodium, quaternary ammonium or imidazolinium cation,
and in that said binder is a fluoropolymer of high molecular weight andlor
which carries functional group(s) capable of developing adhesion to a
metal substrate.
3 0
2. The material as claimed in claim 1, characterized in that the compounds
of formula A are imidazolates, preferably lithium imidazolates.
3. The material as claimed in either of claims 1 and 2, characterized in that
5 the organic salt(s) represents between 0.01 and 10% and preferably
between 0.05 and 5% by weight, with respect to the total weight of the
material.
4. The material as claimed in any one of claims 1 to 3, characterized in that
10 said binder is a fluoropolymer of high molecular weight, preferably a
fluoropolymer of very high molecular weight, chosen from vinylidene
fluoride and chlorotrifluoroethylene copolymers, and poly(viny1idene
fluoride).
15 5. The material as claimed in one of claims 1 to 4, in which said binder is
poly(viny1idene fluoride) or PVDF having a melt viscosity of greater than
or equal to 2000 Pas as measured at 232°C under shearing of 100s-"
according to the standard ASTM D3825.
2 0 6. The material as claimed in one of claims 1 to 3, in which said binder is a
PVDF carrying at least one of the following functional groups: carboxylic
acid, carboxylic acid anhydride, carboxylic acid esters, epoxy groups
(such as glycidyl), amide groups, alcohol groups, carbonyl groups,
mercapto groups, sulfide, oxazoline groups and phenol groups.
2 5
7. The material as claimed in claim 6, in which the carboxylic acid functional
group is chosen from acrylic acid, methacrylic acid, hydroxyethyl
(meth)acrylate, hydroxypropyl (meth)acrylate and hydroxyethylhexyl
(meth)acrylate.
8. The material as claimed in one of claims 5 to 7, in which the PVDF
corresponds to vinylidene fluoride (VDF) homopolymers or copolymers of
VDF and of at least one other comonomer in which the VDF represents
at least 50 mol%, said comonomer being chosen from vinyl fluoride,
35 trifluoroethylene, chlorotrifluoroethylene (CTFE), 1,2-difluoroethylene,
tetrafluoroethylene (TFE), hexafluoropropylene (HFP), perfluoro(alkyl
vinyl) ethers, such as perfluoro(methyl vinyl) ether (PMVE),
perfluoro(ethyl vinyl) ether (PEVE) or perfluoro(propyl vinyl) ether
(PPVE), perfluoro(l,3-dioxole), perfluoro(2,2-dimethyl-1,3-dioxole)
(PDD), the product of formula CF2=CFOCF2CF(CF3)0CF2CF2X in which
X is SOZF, COZH, CHzOH, CH20CN or CH20P03H, the product of
5 formula CF2=CFOCF2CF2S02F, the product of formula
F(CFZ),CH~OCF=CFi~n which n is 1, 2, 3, 4 or 5, the product of formula
RICH20CF=CF2 in which R1 is hydrogen or F(CF2), and z has the value
1, 2, 3 or 4, the product of formula R30CF=CH2 in which R3 is F(CF2)=
and z has the value 1, 2, 3 or 4, or also perfluorobutylethylene (PFBE),
10 fluorinated ethylene propylene (FEP), 3,3,3-trifluoropropene, 2-
trifluoromethyl-3,3,3-trifluoro-I-propene, 2,3,3,3-tetrafluoropropene or
HFO-1234yf, E-I ,3,3,3-tetrafluoropropene or HFO-1234zeE, 2-1,3,3,3-
tetrafluoropropene or HFO-1234zeZ, 1 ,I ,2,3-tetrafluoropropene or HFO-
1234yc, 1,2,3,3-tetrafluoropropene or HFO-1234ye, I ,I ,3,3-
15 tetrafluoropropene or HFO-1234zc, and chlorotetrafluoropropene or
HCFO-1224.
9. The material as claimed in any one of the preceding claims,
characterized in that the electron-conducting additive is chosen from the
2 0 different allotropic forms of carbon or conducting organic polymers.
10.A process for the preparation of the material as claimed in any one of
claims 1 to 9, characterized in that it comprises (i) at least a stage of
preparation of a suspension involving:
2 5 - one or more organic salts of formula A andlor B;
- an electron-conducting additive;
- a polymer binder as claimed in one of claims 4 to 8;
- one or more volatile solvents;
- an electrode active material chosen from a lithium oxide, phosphate,
30 fluorophosphate or silicate, and
ii) a stage of preparation of a film starting from the suspension prepared
in (i).
11.The process as claimed in claim 10, characterized in that the volatile
3 5 solvent(s) is or are chosen from organic solvents and water.
12.The process as claimed in claim 11, characierized in that the organic
solvents are chosen from N-methylpyrrolidone or dimethyl suifoxide.
13.A Li-ion battery, comprising the rnaterial as claimed in any one of ciaims
5 I to 9.
I4.The use of at least one salt of formula A andlor B as ion-conducting
additive in the manufacture of an electrode composite material.