EP3105805A1 - Lithium-ion battery comprising a lithium-rich cathode and a graphite-based anode - Google Patents

Lithium-ion battery comprising a lithium-rich cathode and a graphite-based anode

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Publication number
EP3105805A1
EP3105805A1 EP15706904.8A EP15706904A EP3105805A1 EP 3105805 A1 EP3105805 A1 EP 3105805A1 EP 15706904 A EP15706904 A EP 15706904A EP 3105805 A1 EP3105805 A1 EP 3105805A1
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EP
European Patent Office
Prior art keywords
lithium
positive electrode
battery according
negative electrode
electrode
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP15706904.8A
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German (de)
French (fr)
Inventor
Irina Profatilova
Lise Daniel
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Renault SAS
Original Assignee
Renault SAS
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Filing date
Publication date
Application filed by Renault SAS filed Critical Renault SAS
Publication of EP3105805A1 publication Critical patent/EP3105805A1/en
Withdrawn legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G53/00—Compounds of nickel
    • C01G53/40—Nickelates
    • C01G53/42—Nickelates containing alkali metals, e.g. LiNiO2
    • C01G53/44—Nickelates containing alkali metals, e.g. LiNiO2 containing manganese
    • C01G53/50—Nickelates containing alkali metals, e.g. LiNiO2 containing manganese of the type [MnO2]n-, e.g. Li(NixMn1-x)O2, Li(MyNixMn1-x-y)O2
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0568—Liquid materials characterised by the solutes
    • H—ELECTRICITY
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    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
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    • H01M10/058—Construction or manufacture
    • H—ELECTRICITY
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    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/44—Methods for charging or discharging
    • H01M10/446—Initial charging measures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • H01M4/0402—Methods of deposition of the material
    • H01M4/0404—Methods of deposition of the material by coating on electrode collectors
    • H—ELECTRICITY
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    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
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    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
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    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1391—Processes of manufacture of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
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    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1393—Processes of manufacture of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
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    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • H—ELECTRICITY
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    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/621—Binders
    • H01M4/622—Binders being polymers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/621—Binders
    • H01M4/622—Binders being polymers
    • H01M4/623—Binders being polymers fluorinated polymers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/01—Particle morphology depicted by an image
    • C01P2004/03—Particle morphology depicted by an image obtained by SEM
    • H—ELECTRICITY
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    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M2010/4292—Aspects relating to capacity ratio of electrodes/electrolyte or anode/cathode
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the invention relates to the general field of lithium-ion rechargeable batteries.
  • the invention relates to rechargeable lithium - ion batteries comprising a lithium rich positive electrode material and a graphite - based negative electrode material.
  • the invention also relates to a method for preparing lithium-ion batteries comprising such electrodes.
  • the invention relates to a method for cycling lithium-ion batteries comprising such electrodes, with moderate capacities making it possible to improve the life of a lithium-ion battery cell.
  • the Li-ion batteries comprise one or more positive electrode (s), one or more negative electrode (s), an electrolyte and a separator composed of a porous polymer or any other suitable material so to avoid any direct contact between the electrodes.
  • Li-ion batteries are increasingly being used as an autonomous power source, particularly in applications related to electric mobility. This trend can be explained in particular by densities of mass and volumetric energy which are much higher than those of conventional nickel cadmium (Ni-Cd) and nickel-metal hydride (Ni-MH) accumulators, an absence of memory effect, a self-discharge low compared to other accumulators and also by a drop in costs per kilowatt hour related to this technology.
  • Ni-Cd nickel cadmium
  • Ni-MH nickel-metal hydride
  • Carbon based materials in particular graphite, have been successfully developed and widely marketed as electrochemically active negative electrode materials for Li-ion batteries. These materials are particularly effective because of their structure conducive to intercalation and deintercalation lithium and their stability during different charging and discharging cycles.
  • Li-ion batteries comprising negative electrode graphite materials are generally designed so that the reversible capacitance (N) of the negative electrode is greater than the reversible capacitance (P) of the positive electrode (P. Arora, RE White, Capacity fade mechanism and side reactions in lithium-ion batteries, J. Electrochem Soc, Vol 145 (1998) 3647-3667, B. Son, M.-H. Ryou, J. Choi, S. Kim, JM Ko, YM Lee, Effect of cathode / anode area on the electrochemical performance of lithium-ion batteries, J. Power Sources, Vol 243 (2013) 641-647, Y. Li, M. Bettge, B. Polzin, Y. Zhu, M. Balasubramanian, DP Abraham Understanding Long-Term Cycling Performance of
  • the batteries thus designed have a N / P ratio> 1 (1.05 - 1.3).
  • excess graphite is placed in the cell to prevent lithium plating to the negative electrode during charging and discharging cycles which results in degradation of the battery.
  • this excess graphite leads to a decrease in the specific energy density of the cell.
  • batteries having N / P ratios ⁇ 1 have been designed comprising a lithium titanate (Li 4 TisOi 2, LTO) negative electrode material as described in US2009 / 0035662, US2011 / 0281148 and US2013 / 164584.
  • Li 4 TisOi 2, LTO lithium titanate
  • the LTO-based material is a negative electrode material well known to those skilled in the art which has several specific characteristics. When it is of spinel structure, it has a high operating voltage of about 1.5 V and a theoretical low specific capacitance of 175 mAh / g. With respect to the graphite which has an operating voltage of approximately 0.15 V and a theoretical specific capacity of 372 mAh / g, the LTO-based material therefore has a reduced energy density. Thanks to the tension Because of the high operating efficiency and because of the absence of SEI layer on the surface of this electrode, there is no risk of lithium plating on the surface of the LTO material. On the other hand, the lithiation of graphite can lead to a deposition of metallic lithium during the formation of the "SEI" layer. Thus, it is not possible to design batteries having a N / P ratio ⁇ 1 when the material of the negative electrode is based on graphite.
  • the LTO material is generally used as a nanoscale material to achieve high lithium intercalation / deintercalation kinetics. High power applications are thus appropriate but the associated cost is high.
  • graphite is used as a micron or submicron size material and is generally less expensive than the LTO material.
  • Li-ion batteries Another problem with Li-ion batteries is the ability of said batteries to withstand the repetition of charging and discharging cycles that involve deep discharge, ie, close to 0 volt (V). These charge and deep discharge cycles can decrease the full accessible capacity of said batteries. For example, a battery that has an initial charge of 3 V can, after 150 cycles of charge and deep discharge, have a full accessible capacity significantly lower than the initial capacity.
  • SEI Solid Electrolyte Interphase
  • Li-ion battery cell comprising electrode materials that both avoids the problems of lithium plating and increases the resistance to capacitance loss.
  • the term "lithium-rich positive electrode material" is intended to mean any lamellar oxide of general formula:
  • the invention also relates to a method for preparing Li-ion batteries according to the invention.
  • the subject of the invention is a particular cycling method for the batteries according to the invention.
  • FIG. 1 compares the specific discharge capacities of Li-ion battery cells having different N / P ratios as a function of the number of charge and discharge cycles
  • FIG. 2 represents a scanning electron microscope micrograph of a lithium-rich material for a positive electrode
  • FIG. 3 also shows a scanning electron microscope micrograph of a lithium-rich material for a positive electrode
  • FIG. 4 shows a scanning electron micrograph of a graphite-based material for negative electrode.
  • Li-ion batteries generally include a positive electrode, a negative electrode, a separator between the electrodes and an electrolyte comprising lithium ions.
  • the lithium ions move towards the negative electrode by passing through a separator.
  • the same ions move from the negative electrode to the positive electrode again through a separator.
  • the Li-ion battery according to the invention comprises a lithium-rich positive electrode material.
  • Said electrode material A lithium-rich positive comprises an active material which is generally a lithiated metal oxide selected from nickel, cobalt and / or manganese and optionally another doping metal.
  • the lithium-rich positive electrode material may also include carbon fibers.
  • these are vapor phase growth carbon fibers (VGCF for "Vapor Grown Carbon Fibers") marketed by the company Showa Denko.
  • VGCF vapor phase growth carbon fibers
  • Other types of suitable carbon fibers may be carbon nanotubes, doped nanotubes (possibly graphite), carbon nanofibers, doped nano fibers (possibly graphite), carbon nanotubes single sheets or nanotubes multi-walled carbon. Synthetic methods for these materials may include arc discharge, laser ablation, plasma torch, and chemical vapor phase decomposition.
  • the lithium-rich positive electrode material may further comprise one or more binders.
  • the binder (s) may be chosen from polybutadiene-styrene latices and organic polymers, and preferably from polybutadiene-styrene latices, polyesters, polyethers, methylmethacrylate polymer derivatives, polymeric derivatives and the like. acrylonitrile, methylcellulose carboxyl and its derivatives, polyvinyl acetates or polyacrylate acetate, polyvinylidene fluorides, and mixtures thereof.
  • the Li-ion battery according to the invention comprises a negative electrode material based on graphite.
  • the graphite carbon may be chosen from synthetic graphite carbons, and natural from natural precursors followed by a purification and / or a post treatment.
  • Other active carbon materials may be used such as pyrolytic carbon, amorphous carbon, activated carbon, coke, coal tar pitch and graphene. Mixtures of graphite with one or more of these materials are possible.
  • Materials having a core - shell structure may be used when the core comprises high capacity graphite and when the shell comprises a carbon - based material protecting the core from degradation due to the repeated phenomenon of intercalation / deintercalation of lithium ions. .
  • the graphite negative electrode material may further comprise one or more binders as for the positive electrode.
  • the binders described above for the positive electrode can be used for the negative electrode.
  • the Li-ion battery according to the invention also comprises a separator located between the electrodes. It plays the role of electrical insulator. Several materials can be used as separators.
  • the separators are generally composed of porous polymers, preferably polyethylene and / or polypropylene.
  • the Li-ion battery according to the invention also comprises an electrolyte, preferably a liquid.
  • This electrolyte generally comprises one or more lithium salts and one or more solvents.
  • the lithium salt or salts generally comprise inert anions.
  • Suitable lithium salts may be selected from lithium bis [(trifluoromethyl) sulfonyl] imide (LiN (CF 3 S 0 2 ) 2 ), lithium trifluoromethanesulfonate (LiCF 3 SO 3 ), bis (oxalato) borate lithium (LiBOB), lithium difluoro (oxolato) borate (LiDFOB), lithium bis (perfluoroethylsulfonyl) imide (LiN (CF 3 CF 2 SiO 2 ) 2 ), LiClO 4 , LiAsF 6 , LiPF 6 , LiBF 4, Lil, LiCH 3 S0 3, LiB (C 2 0 4) 2, LiR F SOSR F, LiN (R F S 0 2) 2, liC (R F S0 2) 3, R F is a group selected from fluorine atom and a perfluoroalkyl group having between one and
  • the lithium salt or salts are preferably dissolved in one or more solvents chosen from aprotic polar solvents, for example ethylene carbonate (denoted “EC”), propylene carbonate, dimethyl carbonate, diethyl carbonate (denoted “DEC”) and methyl and ethyl carbonate.
  • aprotic polar solvents for example ethylene carbonate (denoted “EC”), propylene carbonate, dimethyl carbonate, diethyl carbonate (denoted “DEC”) and methyl and ethyl carbonate.
  • the invention also relates to a method for preparing Li-ion batteries according to the invention, comprising the following steps:
  • Q + rev is the reversible surface capacity of the positive electrode (mAh / cm 2 );
  • L denotes the density of active material for the negative electrode (mg / cm);
  • L denotes the density of active material for the positive electrode (mg / cm 2 );
  • Q ' rev.spe refers to the specific reversible capacity of the negative electrode (mAh / mg);
  • Q rev.spe designates the specific reversible capacitance of the positive electrode (mAh / mg),
  • N / P 1, a material for positive electrode rich in lithium as defined above, on a current collector;
  • a method for preparing Li-ion batteries according to the invention comprises the following steps:
  • the invention also relates to a particular cycling method of a Li-ion battery according to the invention comprising the following steps:
  • the cycles being carried out at a capacity of between C / 20 and C, C denoting the capacity of the Li-ion battery.
  • the first activation cycle is at a capacity of C / 10.
  • the following charging and discharging cycles occur at a capacitance of C / 2.
  • a high voltage is used during the activation cycle.
  • This "overvoltage” can be likened to an additional capacity of the lithium-rich positive electrode material.
  • Said material is used as a “sacrificed lithium” material in this step to form SEI ("Solid Electrolyte Interphase") on the graphite-based negative electrode active material.
  • An active material for lithium rich positive electrode is provided by Umicore and has the formula Lii i2 Mno, 5Nio, 2Coo, i 0 2.
  • the positive electrode is prepared by mixing 86% by weight of active material, 3% by weight of Super P® carbon additive, 3% by weight of carbon fiber (VGCF) and 8% by weight of dissolved polyvinylidene fluoride. in N-methyl-2-pyrrolidone (NMP).
  • Two types of electrode are prepared, one for comparison and one according to the invention.
  • the two electrodes are manufactured by depositing the mixture respectively on an aluminum sheet 20 ⁇ thick.
  • the electrodes are dried and calendered at 80 ° C so that they each have a porosity of 35%.
  • Figures 2 and 3 show snapshots with a scanning electron microscope of the positive electrode thus manufactured. Preparation of the negative electrode
  • Active graphite material is provided by Hitachi (SMGHE2). Two types of electrode are prepared, one for comparison and one according to the invention, by mixing 96% by weight of graphite, 2% by weight of carboxyl methyl cellulose (CMC) and 2% by weight of Styrofan latex, c. that is, a carboxylated styrene-butadiene copolymer.
  • CMC carboxyl methyl cellulose
  • Styrofan latex c. that is, a carboxylated styrene-butadiene copolymer.
  • the resulting mixture is respectively deposited on a copper sheet 15 ⁇ thick and then dried and compressed by calendering at 80 ° C.
  • the negative electrodes thus manufactured each have a porosity of 43%.
  • the density of electrode material is 4.46 mg / cm 2
  • FIG. 4 represents a scanning electron microscope photograph of the positive electrode thus produced.
  • Table 1 shows that the positive electrode is designed such that a specific reversible surface capacitance of 1.25 mAh / cm 2 is measured. A specific reversible surface capacitance of 1.58 mAh / cm 2 is measured for the negative electrode.
  • Table 1 shows that the positive electrode is designed such that a specific reversible surface capacitance of 1.77 mAh / cm 2 is measured. A specific reversible surface capacity of 1.77 mAh / cm 2 is measured for the negative electrode.
  • the Celgard® 2500 separator is used to prevent short circuits between the positive electrode and the negative electrode during charging and discharging cycles.
  • the area of this separator is 16 cm 2 .
  • the electrolyte used is a mixture of ethylene carbonate, methyl ethyl carbonate and dimethyl carbonate (EC / EMC / DMC) in a ratio 1/1/1 by volume with the lithium salt LiPF 6 at 1M.
  • the Celgard® 2500 separator is a microporous single-layer membrane with a thickness of 25 ⁇ made of polypropylene.
  • FIG. 1 shows a graph comparing the specific discharge capacities of three Li-ion battery cells each comprising a lithium-rich positive electrode material and a graphite-based negative electrode material. with different N / P ratios depending on the number of charge and discharge cycles.
  • FIG. 1 clearly shows that the electrochemical behavior (curve A) is very unstable with respect to the cell of the battery A. A drop in electrochemical performance is observed and a specific discharge capacity of about 100 mAh / g is measured after about 150 cycles.
  • Figure 1 shows on the other hand that the electrochemical performances (curves B and C respectively) of the cells of the battery B and the battery C are similar after about 1 80 cycles. Indeed, a specific discharge capacity of about 150 mAh / g is measured for the 2 cells.
  • the analysis of FIG. 1 therefore firstly shows that by using the cycling method according to the invention, a clear improvement in the electrochemical performances is observed. It further results from the analysis of Figure 1 that it is no longer necessary to put excess graphite in a Li-ion battery cell. As a result, the energy density of the cell is increased.

Abstract

The subject of the invention is a lithium-ion battery comprising a graphite-based material for negative electrode, a lithium-rich material for positive electrode, an electrolyte and a separator, characterized in that the reversible capacity (N) of said negative electrode is equal to the reversible capacity (P) of said positive electrode so that said battery exhibits a ratio N/P = 1. The subject of the invention is also a method of preparing Li‑ion batteries according to the invention. Finally, the subject of the invention is a method of cycling a lithium-ion battery according to the invention.

Description

BATTERIE LITHIUM-ION C OMPRENANT UNE CATHODE RICHE EN LITHIUM ET UNE ANODE A BASE DE GRAPHITE L 'invention concerne le domaine général des batteries rechargeables lithium-ion.  The invention relates to the general field of lithium-ion rechargeable batteries.
Plus précisément, l 'invention concerne les batteries rechargeables lithium-ion comprenant un matériau pour électrode positive riche en lithium et un matériau pour électrode négative à base de graphite .  More specifically, the invention relates to rechargeable lithium - ion batteries comprising a lithium rich positive electrode material and a graphite - based negative electrode material.
L 'invention concerne également un procédé de préparation de batteries lithium-ion comprenant de telles électrodes .  The invention also relates to a method for preparing lithium-ion batteries comprising such electrodes.
Enfin, l' invention concerne un procédé de cyclage de batteries lithium-ion comprenant de telles électrodes, à des capacités modérées permettant d' améliorer la durée de vie d'une cellule de batterie lithium-ion.  Finally, the invention relates to a method for cycling lithium-ion batteries comprising such electrodes, with moderate capacities making it possible to improve the life of a lithium-ion battery cell.
Classiquement, les batteries Li-ion comprennent une ou plusieurs électrode(s) positive(s), une ou plusieurs électrode(s) négative(s), un électrolyte et un séparateur composé d'un polymère poreux ou de tout autre matériau approprié afin d ' éviter tout contact direct entre les électrodes .  Conventionally, the Li-ion batteries comprise one or more positive electrode (s), one or more negative electrode (s), an electrolyte and a separator composed of a porous polymer or any other suitable material so to avoid any direct contact between the electrodes.
Les batteries Li-ion sont de plus en plus utilisées comme source d'énergie autonome, en particulier dans les applications liées à la mobilité électrique. Cette tendance s'explique notamment par des densités d'énergie massique et vo lumique nettement supérieures à celles des accumulateurs classiques nickel cadmium (Ni-Cd) et nickel- hydrure métallique (Ni-MH), une absence d' effet mémoire, une autodécharge faible par rapport à d' autres accumulateurs et également par une baisse des coûts au kilowatt-heure liée à cette technologie.  Li-ion batteries are increasingly being used as an autonomous power source, particularly in applications related to electric mobility. This trend can be explained in particular by densities of mass and volumetric energy which are much higher than those of conventional nickel cadmium (Ni-Cd) and nickel-metal hydride (Ni-MH) accumulators, an absence of memory effect, a self-discharge low compared to other accumulators and also by a drop in costs per kilowatt hour related to this technology.
Les matériaux à base de carbone, en particulier de graphite ont été développés avec succès et largement commercialisés comme matériaux électrochimiquement actifs d'électrode négative pour accumulateurs Li-ion. Ces matériaux sont particulièrement performants du fait de leur structure propice à l'intercalation et la désintercalation du lithium et de leur stabilité au cours des différents cycles de charge et de décharge. Carbon based materials, in particular graphite, have been successfully developed and widely marketed as electrochemically active negative electrode materials for Li-ion batteries. These materials are particularly effective because of their structure conducive to intercalation and deintercalation lithium and their stability during different charging and discharging cycles.
Les batteries Li-ion comprenant des matériaux à base de graphite pour électrode négative sont généralement conçues de telle sorte que la capacité réversible (N) de l'électrode négative est supérieure à la capacité réversible (P) de l'électrode positive (P. Arora, R.E. White. Capacity fade mechanism and side reactions in lithium-ion batteries. J. Electrochem. Soc, Vol. 145 (1998) 3647-3667 ; B. Son, M. -H. Ryou, J. Choi, S. -H. Kim, J. M. Ko, Y. M. Lee. Effect of cathode/anode area ratio on electrochemical performance of lithium-ion batteries. J. Power Sources, Vol. 243 (2013) 641-647; Y. Li, M. Bettge, B. Polzin, Y. Zhu, M. Balasubramanian, D.P. Abraham. Understanding Long-Term Cycling Performance of Li-ion batteries comprising negative electrode graphite materials are generally designed so that the reversible capacitance (N) of the negative electrode is greater than the reversible capacitance (P) of the positive electrode (P. Arora, RE White, Capacity fade mechanism and side reactions in lithium-ion batteries, J. Electrochem Soc, Vol 145 (1998) 3647-3667, B. Son, M.-H. Ryou, J. Choi, S. Kim, JM Ko, YM Lee, Effect of cathode / anode area on the electrochemical performance of lithium-ion batteries, J. Power Sources, Vol 243 (2013) 641-647, Y. Li, M. Bettge, B. Polzin, Y. Zhu, M. Balasubramanian, DP Abraham Understanding Long-Term Cycling Performance of
Li1.2Ni0.15Mn0.55Coo.102-Graphite Lithium-Ion Cells. J. Electrochem. Soc, 160 (5) A3006-A3019 (2013;). Un ratio N/P est alors défini. Li 1 . 2 Ni 0 . 15 Mn 0 . 55 Coo. 1 0 2 -Graphite Lithium-Ion Cells. J. Electrochem. Soc., 160 (5) A3006-A3019 (2013; A N / P ratio is then defined.
Les batteries ainsi conçues présentent un ratio N/P > 1 (1,05 - 1,3). Ainsi, du graphite en excès est placé dans la cellule afin d'éviter le plaquage de lithium à l'électrode négative durant les cycles de charge et de décharge qui entraîne une dégradation de la batterie. Cependant, cet excès de graphite mène à une diminution de la densité d'énergie spécifique de la cellule.  The batteries thus designed have a N / P ratio> 1 (1.05 - 1.3). Thus, excess graphite is placed in the cell to prevent lithium plating to the negative electrode during charging and discharging cycles which results in degradation of the battery. However, this excess graphite leads to a decrease in the specific energy density of the cell.
Pour faire face à ces problèmes, des batteries présentant des ratios N/P < 1 ont été conçues comprenant un matériau pour électrode négative à base de titanate de lithium (Li4TisOi2, LTO) comme le décrivent les documents suivants US2009/0035662, US2011/0281148 et US2013/164584. To cope with these problems, batteries having N / P ratios <1 have been designed comprising a lithium titanate (Li 4 TisOi 2, LTO) negative electrode material as described in US2009 / 0035662, US2011 / 0281148 and US2013 / 164584.
Le matériau à base de LTO est un matériau pour électrode négative bien connu de l'homme du métier qui possède plusieurs caractéristiques spécifiques. Quand il est de structure spinelle, il présente une tension de fonctionnement élevée d'environ 1,5 V et une faible capacité spécifique théorique de 175 mAh/g. Par rapport au graphite qui présente une tension de fonctionnement d'environ 0,15 V et une capacité spécifique théorique de 372 mAh/g, le matériau à base de LTO présente donc une densité d'énergie réduite. Grâce à la tension de fonctionnement élevée et du fait de l ' absence de couche SEI à la surface de cette électrode, il n 'y a aucun risque de plaquage de lithium à la surface du matériau à base de LTO . En revanche, la lithiation du graphite peut entraîner un dépôt de lithium métallique lors de la formation de la couche « SEI » . Ainsi, il n' est pas possible de concevoir des batteries présentant un ratio N/P < 1 lorsque le matériau de l ' électrode négative est à base de graphite. The LTO-based material is a negative electrode material well known to those skilled in the art which has several specific characteristics. When it is of spinel structure, it has a high operating voltage of about 1.5 V and a theoretical low specific capacitance of 175 mAh / g. With respect to the graphite which has an operating voltage of approximately 0.15 V and a theoretical specific capacity of 372 mAh / g, the LTO-based material therefore has a reduced energy density. Thanks to the tension Because of the high operating efficiency and because of the absence of SEI layer on the surface of this electrode, there is no risk of lithium plating on the surface of the LTO material. On the other hand, the lithiation of graphite can lead to a deposition of metallic lithium during the formation of the "SEI" layer. Thus, it is not possible to design batteries having a N / P ratio <1 when the material of the negative electrode is based on graphite.
De plus, le matériau à base de LTO est généralement utilisé en tant que matériau de taille nanométrique pour atteindre des cinétiques d'intercalation/désintercalation d ' ions lithium élevées. Les applications haute puissance sont ainsi appropriées mais le coût associé est élevé. De son côté, le graphite est utilisé en tant que matériau de taille micronique ou submicronique et est généralement moins cher que le matériau à base de LTO .  In addition, the LTO material is generally used as a nanoscale material to achieve high lithium intercalation / deintercalation kinetics. High power applications are thus appropriate but the associated cost is high. For its part, graphite is used as a micron or submicron size material and is generally less expensive than the LTO material.
Une autre problématique liée aux batteries Li-ion concerne la capacité desdites batteries à supporter la répétition des cycles de charge et de décharge qui impliquent une décharge profonde, c ' est-à- dire proche de 0 vo lt (V) . Ces cycles de charge et de décharge profonde peuvent diminuer la pleine capacité accessible desdites batteries . Par exemple, une batterie qui a une charge initiale de 3 V peut, après 150 cycles de charge et de décharge profonde, avoir une pleine capacité accessible nettement inférieure à la capacité initiale.  Another problem with Li-ion batteries is the ability of said batteries to withstand the repetition of charging and discharging cycles that involve deep discharge, ie, close to 0 volt (V). These charge and deep discharge cycles can decrease the full accessible capacity of said batteries. For example, a battery that has an initial charge of 3 V can, after 150 cycles of charge and deep discharge, have a full accessible capacity significantly lower than the initial capacity.
Une conséquence de cet affaiblissement de capacité est la nécessité de recharger fréquemment la batterie, ce qui est peu pratique pour l 'utilisateur.  A consequence of this loss of capacity is the need to frequently recharge the battery, which is inconvenient for the user.
Les cycles de charge et de décharge sont également à l ' origine d'un autre phénomène. Des produits issus des réactions thermodynamiques se déroulant au sein d'un accumulateur Li-ion s ' accumulent sur la surface du matériau actif pour former une couche appelée « Solid Electrolyte Interphase » (SEI) . Cette SEI est un élément essentiel au bon fonctionnement de l ' accumulateur Li-ion, bien que responsable de l' importante capacité irréversible observée lors du premier cycle, car non seulement elle conduit très bien les ions lithium mais elle présente aussi l ' avantage de stopper la décomposition catalytique du solvant. Charge and discharge cycles are also the cause of another phenomenon. Products resulting from thermodynamic reactions taking place in a Li-ion accumulator accumulate on the surface of the active material to form a layer called "Solid Electrolyte Interphase" (SEI). This SEI is an essential element for the proper functioning of the Li - ion accumulator, although it is responsible for the large irreversible capacity observed during the first cycle, because it not only conducts ions very well. lithium, but it also has the advantage of stopping the catalytic decomposition of the solvent.
Il serait donc avantageux de fournir une cellule de batterie Li- ion comprenant des matériaux pour électrodes permettant à la fois d' éviter les problèmes liés au plaquage de lithium et d' augmenter la résistance à l ' affaiblissement de capacité .  It would therefore be advantageous to provide a Li-ion battery cell comprising electrode materials that both avoids the problems of lithium plating and increases the resistance to capacitance loss.
Il a maintenant été découvert qu'un procédé de cyclage particulier d'une batterie Li-ion, présentant un ratio N/P = 1 et comprenant un matériau pour électrode négative à base de graphite, conduisait à l'obtention de performances électrochimiques similaires à celles de batteries Li-ion comprenant ledit même matériau pour électrode négative et présentant un ratio N/P > 1 . L 'immense avantage réside dans le fait que l ' excès de graphite n' est plus nécessaire menant par conséquent à une augmentation de la densité d' énergie de la cellule.  It has now been discovered that a particular cycling process of a Li-ion battery, having a N / P ratio = 1 and comprising a graphite-based negative electrode material, resulted in obtaining electrochemical performances similar to those of Li-ion batteries comprising the same material for negative electrode and having a ratio N / P> 1. The immense advantage lies in the fact that the excess graphite is no longer necessary therefore leading to an increase in the energy density of the cell.
Après un premier cycle d' activation du matériau riche en lithium pour électrode positive à une tension > 4,4 V, les cycles de charge et de décharge suivants se déroulent à des tensions réduites et en utilisant une capacité réduite C, C désignant la capacité de la batterie Li-ion. Ce procédé de cyclage particulier est connu de l ' art antérieur comme le montre le document US 2012/0056590 qui décrit ledit procédé pour des batteries Li-ion comprenant un matériau pour électrode positive riche en lithium et un matériau pour électrode négative pouvant intercaler du lithium.  After a first activation cycle of the positive electrode lithium rich material at a voltage> 4.4 V, the following charging and discharging cycles take place at reduced voltages and using a reduced capacitance C, C denoting the capacitance of the Li-ion battery. This particular cycling method is known from the prior art as shown in US 2012/0056590 which describes said method for Li-ion batteries comprising a lithium-rich positive electrode material and a negative-electrode material that can intercalate lithium. .
L 'invention a donc pour obj et une batterie lithium-ion comprenant un matériau pour électrode négative à base de graphite, un matériau pour électrode positive riche en lithium, un séparateur et un électrolyte, la capacité réversible (N) de ladite électrode négative étant égale à la capacité réversible (P) de ladite électrode positive de telle sorte que ladite batterie présente un ratio N/P = 1 , le ratio N/P étant défini par l ' équation ( 1 ) telle que décrite ci-dessus. Dans la suite de la présente demande, il est entendu par « matériau pour électrode positive riche en lithium » tout oxyde lamellaire de formule générale :  The invention is therefore obj and a lithium-ion battery comprising a graphite-based negative electrode material, a lithium-rich positive electrode material, a separator and an electrolyte, the reversible capacitance (N) of said negative electrode being equal to the reversible capacitance (P) of said positive electrode such that said battery has a ratio N / P = 1, the ratio N / P being defined by equation (1) as described above. In the remainder of the present application, the term "lithium-rich positive electrode material" is intended to mean any lamellar oxide of general formula:
xLi2Mn03 . ( l -x)LiM03 où M représente un ou plusieurs éléments de transition. xLi 2 Mn0 3 . (l-x) LiMO 3 where M represents one or more transition elements.
L 'invention a également pour obj et un procédé de préparation de batteries Li-ion selon l' invention. The invention also relates to a method for preparing Li-ion batteries according to the invention.
Enfin, l' invention a pour objet un procédé de cyclage particulier pour les batteries selon l' invention.  Finally, the subject of the invention is a particular cycling method for the batteries according to the invention.
D ' autres avantages et caractéristiques de l' invention apparaîtront plus clairement à l ' examen de la description détaillée et des dessins annexés sur lesquels :  Other advantages and features of the invention will appear more clearly on examination of the detailed description and the attached drawings in which:
- la figure 1 compare les capacités de décharge spécifiques de cellules de batteries Li-ion présentant différents ratio s N/P en fonction du nombre de cycle de charge et de décharge,  FIG. 1 compares the specific discharge capacities of Li-ion battery cells having different N / P ratios as a function of the number of charge and discharge cycles,
- la figure 2 représente un cliché au microscope électronique à balayage d'un matériau riche en lithium pour électrode positive,  FIG. 2 represents a scanning electron microscope micrograph of a lithium-rich material for a positive electrode,
- la figure 3 représente également un cliché au microscope électronique à balayage d'un matériau riche en lithium pour électrode positive,  FIG. 3 also shows a scanning electron microscope micrograph of a lithium-rich material for a positive electrode,
- la figure 4 représente un cliché au microscope électronique à balayage d'un matériau à base de graphite pour électrode négative.  - Figure 4 shows a scanning electron micrograph of a graphite-based material for negative electrode.
Dans la description de l' invention, le terme « à base de » est synonyme de « comprenant majoritairement » .  In the description of the invention, the term "based on" is synonymous with "comprising predominantly".
Les batteries Li-ion comprennent généralement une électrode positive, une électrode négative, un séparateur entre les électrodes et un électrolyte comprenant des ions lithiums . Lors d'un cycle de charge d'une batterie Li-ion, les ions lithium se déplacent vers l ' électrode négative en passant au travers d'un séparateur. Lors du cycle de décharge, les mêmes ions se déplacent de l ' électrode négative vers l ' électrode positive en passant à nouveau au travers d'un séparateur.  Li-ion batteries generally include a positive electrode, a negative electrode, a separator between the electrodes and an electrolyte comprising lithium ions. During a charge cycle of a Li-ion battery, the lithium ions move towards the negative electrode by passing through a separator. During the discharge cycle, the same ions move from the negative electrode to the positive electrode again through a separator.
La batterie Li-ion selon l' invention est conçue de telle sorte que ladite batterie présente un ratio N/P = 1 .  The Li-ion battery according to the invention is designed such that said battery has a ratio N / P = 1.
La batterie Li-ion selon l' invention comprend un matériau pour électrode positive riche en lithium. Ledit matériau pour électrode positive riche en lithium comprend un matériau actif qui est généralement un oxyde lithié de métal choisi parmi le nickel, le cobalt et/ou le manganèse et éventuellement un autre métal dopant. Le matériau actif pour électrode positive riche en lithium est de formule Lii +x(MaDb) i -x02, dans laquelle M représente un métal ou plusieurs métaux choisi(s) parmi le nickel, le manganèse et le cobalt, x est compris entre 0,01 et 0,33 , D représente un métal ou plusieurs métaux dopant(s) choisi(s) parmi Na, Zn, Cd, Mg, Ti, Ca, Zr, Sr, Ba, Al ou K, b est compris entre 0 et 0 ,05 et a + b = 1 . The Li-ion battery according to the invention comprises a lithium-rich positive electrode material. Said electrode material A lithium-rich positive comprises an active material which is generally a lithiated metal oxide selected from nickel, cobalt and / or manganese and optionally another doping metal. The active material for a lithium-rich positive electrode is of formula Li 1 + x (M a Db) 1- x O 2, in which M represents a metal or several metals chosen from nickel, manganese and cobalt, x is between 0.01 and 0.33, D represents a metal or several doping metals chosen from Na, Zn, Cd, Mg, Ti, Ca, Zr, Sr, Ba, Al or K, b is between 0 and 0, 05 and a + b = 1.
Outre le matériau actif, le matériau pour électrode positive riche en lithium peut également comprendre des fibres de carbone. De préférence, ce sont des fibres de carbone à croissance en phase vapeur (VGCF pour « Vapor Grown Carbon Fibers ») commercialisées par la société Showa Denko . D ' autres types de fibres de carbone appropriés peuvent être des nanotubes de carbone, des nanotubes dopés (éventuellement au graphite), des nano fibres de carbone, des nano fibres dopées (éventuellement au graphite), des nanotubes de carbone mono feuillets ou des nanotubes de carbone multifeuillets. Les méthodes de synthèse relatives à ces matériaux peuvent inclure une décharge par arc, une ablation laser, une torche à plasma et une décomposition chimique en phase vapeur.  In addition to the active material, the lithium-rich positive electrode material may also include carbon fibers. Preferably, these are vapor phase growth carbon fibers (VGCF for "Vapor Grown Carbon Fibers") marketed by the company Showa Denko. Other types of suitable carbon fibers may be carbon nanotubes, doped nanotubes (possibly graphite), carbon nanofibers, doped nano fibers (possibly graphite), carbon nanotubes single sheets or nanotubes multi-walled carbon. Synthetic methods for these materials may include arc discharge, laser ablation, plasma torch, and chemical vapor phase decomposition.
Le matériau pour électrode positive riche en lithium peut en outre comprendre un ou plusieurs liants .  The lithium-rich positive electrode material may further comprise one or more binders.
De manière préférée, le ou les liants peuvent être choisis parmi les latex de polybutadiène-styrène et les polymères organiques, et de préférence parmi les latex de polybutadiène-styrène, les polyesters, les polyéthers, les dérivés polymère de méthylméthacrylate, les dérivés polymères d' acrylonitrile, la carboxyle méthyle cellulo se et ses dérivés, les polyvinyles acétates ou polyacrylate acétate, les polyfluorure de vinylidène, et leurs mélanges .  Preferably, the binder (s) may be chosen from polybutadiene-styrene latices and organic polymers, and preferably from polybutadiene-styrene latices, polyesters, polyethers, methylmethacrylate polymer derivatives, polymeric derivatives and the like. acrylonitrile, methylcellulose carboxyl and its derivatives, polyvinyl acetates or polyacrylate acetate, polyvinylidene fluorides, and mixtures thereof.
La batterie Li-ion selon l' invention comprend un matériau pour électrode négative à base de graphite. Le carbone graphite peut être choisi parmi les carbones graphite synthétiques, et naturels à partir de précurseurs naturels suivis d'une purification et/ou d'un post traitement. D ' autres matériaux actifs à base de carbone peuvent être utilisés comme le carbone pyrolitique, le carbone amorphe, le charbon actif, le coke, le brai de houille et le graphène. Des mélanges de graphite avec l 'un ou plusieurs de ces matériaux sont possibles. Des matériaux possédant une structure noyau-enveloppe peuvent être utilisés quand le noyau comprend du graphite haute capacité et lorsque l ' enveloppe comprend un matériau à base de carbone protégeant le noyau de la dégradation liée au phénomène répété de l' intercalation/désintercalation des ions lithiums . The Li-ion battery according to the invention comprises a negative electrode material based on graphite. The graphite carbon may be chosen from synthetic graphite carbons, and natural from natural precursors followed by a purification and / or a post treatment. Other active carbon materials may be used such as pyrolytic carbon, amorphous carbon, activated carbon, coke, coal tar pitch and graphene. Mixtures of graphite with one or more of these materials are possible. Materials having a core - shell structure may be used when the core comprises high capacity graphite and when the shell comprises a carbon - based material protecting the core from degradation due to the repeated phenomenon of intercalation / deintercalation of lithium ions. .
Le matériau pour électrode négative à base de graphite peut en outre comprendre un ou plusieurs liants comme pour l' électrode positive.  The graphite negative electrode material may further comprise one or more binders as for the positive electrode.
Les liants décrits ci-dessus pour l ' électrode positive peuvent être utilisés pour l ' électrode négative.  The binders described above for the positive electrode can be used for the negative electrode.
La batterie Li-ion selon l' invention comprend également un séparateur localisé entre les électrodes. Il joue le rôle d' isolant électrique. Plusieurs matériaux peuvent être utilisés comme séparateurs . Les séparateurs sont généralement composés de polymères poreux, de préférence de polyéthylène et/ou de po lypropylène.  The Li-ion battery according to the invention also comprises a separator located between the electrodes. It plays the role of electrical insulator. Several materials can be used as separators. The separators are generally composed of porous polymers, preferably polyethylene and / or polypropylene.
La batterie Li-ion selon l' invention comprend également un électrolyte, de préférence liquide.  The Li-ion battery according to the invention also comprises an electrolyte, preferably a liquid.
Cet électrolyte comprend généralement un ou plusieurs sels de lithium et un ou plusieurs solvants .  This electrolyte generally comprises one or more lithium salts and one or more solvents.
Le ou les sels de lithium comprennent généralement des anions inertes. Des sels de lithium appropriés peuvent être choisis parmi le bis [(trifluorométhyl)sulfonyl]imide de lithium (LiN(CF3 S 02)2) , le trifluorométhane sulfonate de lithium (LiCF3 S03), le bis(oxalato)borate de lithium (LiBOB), le difluoro(oxolato) borate de lithium (LiDFOB), le bis(perfluoroéthylsulfonyl)imide de lithium (LiN(CF3CF2S 02)2), LiC104, LiAsF6, LiPF6, LiBF4, Lil, LiCH3 S03 , LiB(C204)2, LÏRF S O S RF, LiN(RFS 02)2, LiC(RFS02)3 , RF étant un groupement choisi parmi un atome de fluor et un groupement perfluoroalkyle comportant entre un et huit atomes de carbone. Le ou les sels de lithium sont, de préférence, dissous dans un ou plusieurs solvants choisis parmi les solvants polaires aprotiques, par exemple, le carbonate d'éthylène (noté « EC »), le carbonate de propylène, le carbonate de diméthyle, le carbonate de diéthyle (noté « DEC ») et le carbonate de méthyle et d'éthyle. The lithium salt or salts generally comprise inert anions. Suitable lithium salts may be selected from lithium bis [(trifluoromethyl) sulfonyl] imide (LiN (CF 3 S 0 2 ) 2 ), lithium trifluoromethanesulfonate (LiCF 3 SO 3 ), bis (oxalato) borate lithium (LiBOB), lithium difluoro (oxolato) borate (LiDFOB), lithium bis (perfluoroethylsulfonyl) imide (LiN (CF 3 CF 2 SiO 2 ) 2 ), LiClO 4 , LiAsF 6 , LiPF 6 , LiBF 4, Lil, LiCH 3 S0 3, LiB (C 2 0 4) 2, LiR F SOSR F, LiN (R F S 0 2) 2, liC (R F S0 2) 3, R F is a group selected from fluorine atom and a perfluoroalkyl group having between one and eight carbon atoms. The lithium salt or salts are preferably dissolved in one or more solvents chosen from aprotic polar solvents, for example ethylene carbonate (denoted "EC"), propylene carbonate, dimethyl carbonate, diethyl carbonate (denoted "DEC") and methyl and ethyl carbonate.
L'invention a également pour objet un procédé de préparation de batteries Li-ion selon l'invention, comprenant les étapes suivantes :  The invention also relates to a method for preparing Li-ion batteries according to the invention, comprising the following steps:
- fabrication d'une cellule, comprenant les étapes suivantes :  - manufacture of a cell, comprising the following steps:
- préparation d'une première électrode par dépôt d'une masse donnée en un matériau pour électrode négative à base de graphite tel que défini ci-avant, sur un collecteur de courant,  - Preparation of a first electrode by depositing a given mass of a negative electrode material based on graphite as defined above, on a current collector,
- préparation d'une seconde électrode par dépôt d'une masse adaptée, de telle manière que l'équation (1) telle que définie ci-après :  - Preparation of a second electrode by depositing a suitable mass, such that equation (1) as defined below:
— O zïrev _ L Q *Z rev.spe , . - O zyrev _ L Q * Z rev.spe,.
~Q--r+ev ~ L+xQ r+ev.spe Q ~ - ~ ev r + r + L + xQ ev.spe
dans laquelle Q" rev désigne la capacité réversible surfacique de l'électrode négative (mAh/cm2) ; where Q " re v denotes the reversible surface capacity of the negative electrode (mAh / cm 2 );
Q+ rev désigne la capacité réversible surfacique de l'électrode positive (mAh/cm2) ; Q + rev is the reversible surface capacity of the positive electrode (mAh / cm 2 );
L" désigne la masse surfacique de matériau actif pour l'électrode négative (mg/cm ) ; L " denotes the density of active material for the negative electrode (mg / cm);
L désigne la masse surfacique de matériau actif pour l'électrode positive (mg/cm2) ; L denotes the density of active material for the positive electrode (mg / cm 2 );
Q'rev.spe désigne la capacité réversible spécifique de l'électrode négative (mAh/mg) ; Q ' rev.spe refers to the specific reversible capacity of the negative electrode (mAh / mg);
Q rev.spe désigne la capacité réversible spécifique de l'électrode positive (mAh/mg),  Q rev.spe designates the specific reversible capacitance of the positive electrode (mAh / mg),
soit respectée pour un ratio N/P = 1, en un matériau pour électrode positive riche en lithium tel que défini ci-avant, sur un collecteur de courant ;  is respected for a ratio N / P = 1, a material for positive electrode rich in lithium as defined above, on a current collector;
en d'autres termes, connaissant la masse déposée de matériau pour l'électrode négative, et les valeurs de Q'rev.spe, Q rev.spe et L", l' homme du métier est capable de trouver la masse à déposer de matériau pour l ' électrode positive de manière à ce que le ratio N/P soit égal à 1 ; in other words, knowing the deposited mass of material for the negative electrode, and the values of Q ' rev.spe, Q rev.spe and L " , those skilled in the art are able to find the mass to deposit material for the positive electrode so that the ratio N / P is equal to 1;
- empilement de la première électrode, de la seconde électrode telles que préparées ci-dessus, et d'un séparateur tel que précédemment décrit, situé entre les deux électrodes,  - Stacking the first electrode, the second electrode as prepared above, and a separator as described above, located between the two electrodes,
- imprégnation du séparateur par un électrolyte tel que précédemment décrit,  impregnation of the separator with an electrolyte as previously described,
- assemblage d'une ou plusieurs cellule(s) telle(s) que précédemment fabriquée(s) .  - assembly of one or more cell (s) such as previously manufactured (s).
Il est à noter que les deux étapes de préparation des électrodes par dépôt sont intervertibles.  It should be noted that the two steps of preparation of the electrodes by deposit are intervertible.
Dans un mo de de réalisation préféré, un procédé de préparation de batteries Li-ion selon l' invention comprend les étapes suivantes :  In a preferred embodiment, a method for preparing Li-ion batteries according to the invention comprises the following steps:
- fabrication d'une cellule, comprenant les étapes suivantes :  - manufacture of a cell, comprising the following steps:
- préparation d'une première électrode par dépôt d'une masse donnée en un matériau pour électrode négative à base de graphite telle que défini ci-avant, sur un co llecteur de courant  - Preparation of a first electrode by depositing a given mass of a graphite-based negative electrode material as defined above, on a current collector
- séchage de ladite première électrode  drying of said first electrode
- densification de ladite première électrode densification of said first electrode
- préparation d'une seconde électrode par dépôt d'une masse adaptée, de telle manière que l ' équation ( 1 ) soit respectée pour un ratio N/P = 1 , en un matériau pour électrode positive riche en lithium telle que défini ci- avant, sur un collecteur de courant, - Preparation of a second electrode by deposition of a suitable mass, such that equation (1) is respected for a ratio N / P = 1, a material for positive electrode rich in lithium as defined above. before, on a current collector,
- séchage de ladite seconde électrode,  drying said second electrode,
- densification de ladite seconde électrode, densification of said second electrode,
- empilement de la première électrode, de la seconde électrode telles que préparées ci-dessus, et d'un séparateur tel que précédemment décrit, situé entre les deux électrodes, - imprégnation du séparateur par un électrolyte tel que précédemment décrit, - Stacking the first electrode, the second electrode as prepared above, and a separator as described above, located between the two electrodes, impregnation of the separator with an electrolyte as previously described,
- assemblage d'une ou plusieurs cellule(s) telle(s) que précédemment fabriquée(s) .  - assembly of one or more cell (s) such as previously manufactured (s).
II est à noter que les deux étapes de préparation des électrodes sont intervertibles .  It should be noted that the two electrode preparation steps are intervertible.
L 'invention a également pour obj et un procédé de cyclage particulier d'une batterie Li-ion selon l 'invention comprenant les étapes suivantes :  The invention also relates to a particular cycling method of a Li-ion battery according to the invention comprising the following steps:
- un premier cycle d' activation entre une tension supérieure (Tsup) strictement supérieure à 4,40 V, de préférence comprise entre 4,40 V borne exclue et 4,60 V, et une tension inférieure (Tinf) comprise entre 1 ,60 et 2,50 V, de préférence égale à 2 V, - A first activation cycle between a higher voltage (T sup ) strictly greater than 4.40 V, preferably between 4.40 V excluded terminal and 4.60 V, and a lower voltage (Ti nf ) between 1 , 60 and 2.50 V, preferably equal to 2 V,
- les cycles de charge et de décharge suivants à des tensions comprises entre une tension Tsup comprise entre 4,30 et 4,43 V, de préférence égale à 4,40 V, et une tension Tlnf comprise entre 1 ,60 et 2,50 V, de préférence égale à 2,30 V ; the following charging and discharging cycles at voltages lying between a voltage T sup of between 4.30 and 4.43 V, preferably equal to 4.40 V, and a voltage T lnf of between 1.60 and 2.degree. , 50 V, preferably equal to 2.30 V;
les cycles s ' effectuant à une capacité comprise entre C/20 et C, C désignant la capacité de la batterie Li-ion. the cycles being carried out at a capacity of between C / 20 and C, C denoting the capacity of the Li-ion battery.
Dans un mode de réalisation préféré, le premier cycle d' activation s ' effectue à une capacité de C/ 1 0.  In a preferred embodiment, the first activation cycle is at a capacity of C / 10.
Dans un autre mode de réalisation préféré, les cycles de charge et de décharge suivants s ' effectuent à une capacité de C/2.  In another preferred embodiment, the following charging and discharging cycles occur at a capacitance of C / 2.
Au cours du procédé de cyclage selon l' invention, une tension élevée est utilisée lors du cycle d' activation. Cette « surtension » peut être assimilée à une capacité additionnelle du matériau pour électrode positive riche en lithium. Ledit matériau est utilisé comme un matériau « sacrifié en lithium » lors de cette étape afin de former la SEI (« Solid Electrolyte Interphase ») sur le matériau actif pour électrode négative à base de graphite.  During the cycling process according to the invention, a high voltage is used during the activation cycle. This "overvoltage" can be likened to an additional capacity of the lithium-rich positive electrode material. Said material is used as a "sacrificed lithium" material in this step to form SEI ("Solid Electrolyte Interphase") on the graphite-based negative electrode active material.
La présente invention est illustrée de manière non-limitative par les exemples suivants .  The present invention is illustrated in a nonlimiting manner by the following examples.
Exemples Préparation de Γ électrode positive Examples Preparation of Γ positive electrode
Un matériau actif pour électrode positive riche en lithium est fourni par la société Umicore et a pour formule Lii i2Mno,5Nio,2Coo, i 02. L ' électrode positive est préparée en mélangeant 86% en poids de matériau actif, 3 % en poids d'un additif carbone Super P®, 3 % en poids de fibres de carbone (VGCF) et 8% en poids de polyfluorure de vinylidène dissous dans du N-méthyl-2-pyrrolidone (NMP) . An active material for lithium rich positive electrode is provided by Umicore and has the formula Lii i2 Mno, 5Nio, 2Coo, i 0 2. The positive electrode is prepared by mixing 86% by weight of active material, 3% by weight of Super P® carbon additive, 3% by weight of carbon fiber (VGCF) and 8% by weight of dissolved polyvinylidene fluoride. in N-methyl-2-pyrrolidone (NMP).
Deux types d' électrode sont préparés, une à titre comparatif et une selon l' invention. Les deux électrodes sont fabriquées en déposant respectivement le mélange sur une feuille d' aluminium de 20 μιη d' épaisseur. Les électrodes sont séchées et compressées par calandrage à 80°C de telle sorte qu' elles présentent chacune une porosité de 35 % .  Two types of electrode are prepared, one for comparison and one according to the invention. The two electrodes are manufactured by depositing the mixture respectively on an aluminum sheet 20 μιη thick. The electrodes are dried and calendered at 80 ° C so that they each have a porosity of 35%.
Afin que la densité de matériau pour électrode soit de 5 ,65 mg/cm2, valeur régie par l ' équation ( 1 ), l' épaisseur finale dudit matériau pour électrode pour la batterie Li-ion présentant un ratio N/P = 1 ,26 est de 52 μιη. In order for the electrode material density to be 5.65 mg / cm 2 , a value governed by equation (1), the final thickness of said electrode material for the Li-ion battery having a ratio of N / P = 1 , 26 is 52 μιη.
Afin que la densité de matériau pour électrode soit de 8 , 15 mg/cm2, valeur régie par l ' équation ( 1 ), l ' épaisseur finale dudit matériau pour électrode pour la batterie Li-ion présentant un ratio N/P = 1 est de 60 μιη. In order for the electrode material density to be 8.15 mg / cm 2 , a value governed by equation (1), the final thickness of said electrode material for the Li-ion battery having a ratio of N / P = 1 is 60 μιη.
Les figures 2 et 3 représentent des clichés au microscope électronique à balayage de l ' électrode positive ainsi fabriquée. Préparation de l 'électrode négative  Figures 2 and 3 show snapshots with a scanning electron microscope of the positive electrode thus manufactured. Preparation of the negative electrode
Un matériau actif de graphite est fourni par la société Hitachi (SMGHE2). Deux types d' électrode sont préparés, une à titre comparatif et une selon l' invention, en mélangeant 96% en poids de graphite, 2% en poids de carboxyle méthyle cellulose (CMC) et 2% en poids de latex Styrofan®, c ' est-à-dire un copolymère styrène- butadiène carboxylé.  Active graphite material is provided by Hitachi (SMGHE2). Two types of electrode are prepared, one for comparison and one according to the invention, by mixing 96% by weight of graphite, 2% by weight of carboxyl methyl cellulose (CMC) and 2% by weight of Styrofan latex, c. that is, a carboxylated styrene-butadiene copolymer.
Le mélange résultant est respectivement déposé sur une feuille de cuivre de 15 μιη d' épaisseur puis séché et compressé par calandrage à 80°C . Les électrodes négatives ainsi fabriquées présentent chacune une porosité de 43 % . The resulting mixture is respectively deposited on a copper sheet 15 μιη thick and then dried and compressed by calendering at 80 ° C. The negative electrodes thus manufactured each have a porosity of 43%.
Afin que la densité de matériau pour électrode soit de 4 ,46 mg/cm2, l ' épaisseur finale dudit matériau pour électrode pour la batterie Li-ion présentant un ratio N/P = 1 ,26 est de 41 μιη. So that the density of electrode material is 4.46 mg / cm 2 , the final thickness of said electrode material for the Li-ion battery having a ratio N / P = 1, 26 is 41 μιη.
Afin que la densité de matériau pour électrode soit de 5 ,05 mg/cm2, l ' épaisseur finale dudit matériau pour électrode pour la batterie Li-ion présentant un ratio N/P = 1 est de 46 μιη. So that the electrode material density is 5.05 mg / cm 2 , the final thickness of said electrode material for the Li-ion battery having a ratio N / P = 1 is 46 μιη.
La figure 4 représente un cliché au microscope électronique à balayage de l ' électrode positive ainsi fabriquée.  FIG. 4 represents a scanning electron microscope photograph of the positive electrode thus produced.
Caractéristiques des électrodes Characteristics of the electrodes
Les caractéristiques détaillées des électrodes sont présentées dans le tableau 1 ci-dessous :  The detailed characteristics of the electrodes are presented in Table 1 below:
spécifique à C/10 (mAh/cm )  Specific to C / 10 (mAh / cm)
Tableau 1 Table 1
En ce qui concerne la batterie Li-ion A comparative, le tableau 1 montre que l'électrode positive est conçue de telle manière qu'une capacité surfacique réversible spécifique de 1,25 mAh/cm2 est mesurée. Une capacité surfacique réversible spécifique de 1,58 mAh/cm2 est mesurée pour l'électrode négative. Ainsi, la batterie A présente un ratio N/P = 1,26. With respect to the comparative Li-ion A battery, Table 1 shows that the positive electrode is designed such that a specific reversible surface capacitance of 1.25 mAh / cm 2 is measured. A specific reversible surface capacitance of 1.58 mAh / cm 2 is measured for the negative electrode. Thus, battery A has a ratio N / P = 1.26.
En ce qui concerne la batterie Li-ion B de l'invention, le tableau 1 montre que l'électrode positive est conçue de telle manière qu'une capacité surfacique réversible spécifique de 1,77 mAh/cm2 est mesurée. Une capacité surfacique réversible spécifique de 1,77 mAh/cm2 est mesurée pour l'électrode négative. Ainsi, la batterie B présente un ratio N/P = 1. With respect to the Li-ion B battery of the invention, Table 1 shows that the positive electrode is designed such that a specific reversible surface capacitance of 1.77 mAh / cm 2 is measured. A specific reversible surface capacity of 1.77 mAh / cm 2 is measured for the negative electrode. Thus, the battery B has a ratio N / P = 1.
Séparateur et électrolyte Separator and electrolyte
Le séparateur Celgard® 2500 est utilisé afin d'éviter tout court-circuit entre l'électrode positive et l'électrode négative durant les cycles de charge et de décharge. L'aire de ce séparateur est de 16 cm2. The Celgard® 2500 separator is used to prevent short circuits between the positive electrode and the negative electrode during charging and discharging cycles. The area of this separator is 16 cm 2 .
L'électrolyte utilisé est un mélange de carbonate d'éthylène, de méthyléthylcarbonate et de diméthylcarbonate (EC/EMC/DMC) selon un ratio 1/1/1 en volume avec le sel de lithium LiPF6 à 1M. Le séparateur Celgard® 2500 est une membrane microporeuse monocouche d 'une épaisseur de 25 μιη composée de polypropylène. The electrolyte used is a mixture of ethylene carbonate, methyl ethyl carbonate and dimethyl carbonate (EC / EMC / DMC) in a ratio 1/1/1 by volume with the lithium salt LiPF 6 at 1M. The Celgard® 2500 separator is a microporous single-layer membrane with a thickness of 25 μιη made of polypropylene.
Performances électrochimiques de cellules de batterie Li-ion La figure 1 représente un graphe comparant les capacités de décharge spécifiques de trois cellules de batteries Li-ion comprenant chacune un matériau pour électrode positive riche en lithium et un matériau pour électrode négative à base de graphite et présentant différents ratios N/P en fonction du nombre de cycle de charge et de décharge. La cellule de la batterie A présente un ratio N/P = 1 ,26. La cellule de la batterie B présente un ratio N/P = 1 , c ' est-à-dire qu ' elle est conçue selon l' invention. La cellule de la batterie C présente un ratio N/P = 1 ,26. Electrochemical Performance of Li-ion Battery Cells Fig. 1 shows a graph comparing the specific discharge capacities of three Li-ion battery cells each comprising a lithium-rich positive electrode material and a graphite-based negative electrode material. with different N / P ratios depending on the number of charge and discharge cycles. The cell of battery A has a ratio N / P = 1, 26. The cell of the battery B has a ratio N / P = 1, that is to say that it is designed according to the invention. The cell of the battery C has a ratio N / P = 1, 26.
Deux procédés de cyclage différents ont été utilisés. En ce qui concerne la cellule de la batterie A, une tension initiale de 4,6 V a été utilisée lors du cycle d' activation à une capacité C/ 10. Les cycles de charge et de décharge suivants se sont déroulés à des tensions comprises entre 4,6 et 2,3 V à une capacité C/2. En revanche, si la tension initiale de 4,6 V a été utilisée lors du cycle d' activation pour les cellules de la batterie B et de la batterie C à une capacité C/ 1 0, les cycles de charge et de décharge suivants se sont déroulés à des tensions réduites comprises entre 4,4 et 2 ,3 V à une capacité C/2.  Two different cycling processes were used. With regard to the battery cell A, an initial voltage of 4.6 V was used during the activation cycle at a C / 10 capacity. The following charge and discharge cycles were conducted at voltages included between 4.6 and 2.3 V at a C / 2 capacity. On the other hand, if the initial voltage of 4.6 V was used during the activation cycle for the cells of battery B and battery C at a capacity of C / 1 0, the following charging and discharging cycles occur. are unwound at reduced voltages of between 4.4 and 2.3 V at a C / 2 capacitance.
Ainsi, si la tension initiale de 4,6 V n' est pas réduite pour les cycles de charge et de décharge suivants, la figure 1 montre clairement que le comportement électrochimique (courbe A) est très instable en ce qui concerne la cellule de la batterie A. Une chute des performances électrochimiques est observée et une capacité de décharge spécifique d' environ 100 mAh/g est mesurée après environ 150 cycles .  Thus, if the initial voltage of 4.6 V is not reduced for the following charging and discharging cycles, FIG. 1 clearly shows that the electrochemical behavior (curve A) is very unstable with respect to the cell of the battery A. A drop in electrochemical performance is observed and a specific discharge capacity of about 100 mAh / g is measured after about 150 cycles.
La figure 1 montre d' autre part que les performances électrochimiques (respectivement courbes B et C) des cellules de la batterie B et de la batterie C sont similaires après environ 1 80 cycles . En effet, une capacité de décharge spécifique d' environ 150 mAh/g est mesurée pour les 2 cellules. L'analyse de la figure 1 montre donc tout d'abord qu'en utilisant le procédé de cyclage selon l'invention, une amélioration nette des performances électrochimiques est observée. Il résulte en outre de l'analyse de la figure 1 qu'il n'est plus nécessaire de mettre du graphite en excès au sein d'une cellule de batterie Li-ion. Par conséquent, la densité d'énergie de la cellule est augmentée. Figure 1 shows on the other hand that the electrochemical performances (curves B and C respectively) of the cells of the battery B and the battery C are similar after about 1 80 cycles. Indeed, a specific discharge capacity of about 150 mAh / g is measured for the 2 cells. The analysis of FIG. 1 therefore firstly shows that by using the cycling method according to the invention, a clear improvement in the electrochemical performances is observed. It further results from the analysis of Figure 1 that it is no longer necessary to put excess graphite in a Li-ion battery cell. As a result, the energy density of the cell is increased.

Claims

REVENDICATIONS
1 . Batterie lithium-ion comprenant un matériau pour électrode négative à base de graphite, un matériau pour électrode positive riche en lithium, un séparateur et un électrolyte caractérisée en que la capacité réversible (N) de ladite électrode négative est égale à la capacité réversible (P) de ladite électrode positive de telle sorte que ladite batterie présente un ratio N/P = 1 . 1. A lithium ion battery comprising a graphite-based negative electrode material, a lithium-rich positive electrode material, a separator and an electrolyte characterized in that the reversible capacitance (N) of said negative electrode is equal to the reversible capacitance (P) ) of said positive electrode such that said battery has a ratio N / P = 1.
2. Batterie selon la revendication 1 , caractérisée en ce que ledit matériau pour électrode positive riche en lithium comprend un matériau actif de formule Lii +x(MaDb) i -x02 , dans laquelle M représente un métal ou plusieurs métaux choisi(s) parmi le nickel, le manganèse et le cobalt, x est compris entre 0 ,0 1 et 0,33 , D représente un métal ou plusieurs métaux dopant(s) choisi(s) parmi Na, Zn, Cd, Mg, Ti, Ca, Zr, Sr, Ba, Al ou K, b est compris entre 0 et 0 ,05 et a + b = 1 . 2. Battery according to claim 1, characterized in that said material for a lithium-rich positive electrode comprises an active material of formula Li 1 + x (M a Db) 1- x O 2, in which M represents a metal or several metals chosen ( s) among nickel, manganese and cobalt, x is between 0.01 and 0.33, D represents a metal or more doping metals selected from Na, Zn, Cd, Mg, Ti , Ca, Zr, Sr, Ba, Al or K, b is 0 to 0.05 and a + b = 1.
3. Batterie selon la revendication 1 ou 2, caractérisée en ce que ledit matériau pour électrode positive riche en lithium comprend des fibres de carbone.  3. Battery according to claim 1 or 2, characterized in that said material for positive electrode rich in lithium comprises carbon fibers.
4. Batterie selon la revendication 3 , caractérisée en ce que les fibres de carbone sont des fibres de carbone à croissance en phase vapeur (VGCF) .  4. Battery according to claim 3, characterized in that the carbon fibers are carbon fibers with vapor phase growth (VGCF).
5. Batterie selon l 'une quelconque des revendications précédentes, caractérisée en ce que ledit matériau pour électrode positive riche en lithium comprend un ou plusieurs liants .  5. Battery according to any one of the preceding claims, characterized in that said lithium-rich positive electrode material comprises one or more binders.
6. Batterie selon la revendication 5 , caractérisée en ce que le ou lesdits liants sont choisis parmi les latex de polybutadiène-styrène et les polymères organiques, et de préférence parmi les latex de polybutadiène-styrène, les polyesters, les polyéthers, les dérivés polymère de méthylméthacrylate, les dérivés polymères d' acrylonitrile, la carboxyle méthyle cellulose et ses dérivés, les polyvinyles acétates ou polyacrylate acétate, les polymères de fluorure de vinylidène, et leurs mélanges . 6. Battery according to claim 5, characterized in that the one or more binders are chosen from polybutadiene-styrene latices and organic polymers, and preferably from polybutadiene-styrene latices, polyesters, polyethers, polymeric derivatives. methylmethacrylate, acrylonitrile polymer derivatives, carboxyl methyl cellulose and its derivatives, polyvinyl acetates or polyacrylate acetate, vinylidene fluoride polymers, and mixtures thereof.
7. Batterie selon l 'une quelconque des revendications précédentes, caractérisée en ce que ledit matériau pour électrode négative à base de graphite comprend un ou plusieurs liants . 7. Battery according to any one of the preceding claims, characterized in that said negative electrode material based on graphite comprises one or more binders.
8. Batterie selon l 'une quelconque des revendications précédentes, caractérisée en ce que ledit séparateur est généralement composé de polymères poreux, de préférence de polyéthylène et/ou de polypropylène.  8. Battery according to any one of the preceding claims, characterized in that said separator is generally composed of porous polymers, preferably polyethylene and / or polypropylene.
9. Batterie selon l 'une quelconque des revendications précédentes, caractérisée en ce que ledit électrolyte comprend un ou plusieurs sels de lithium.  9. Battery according to any one of the preceding claims, characterized in that said electrolyte comprises one or more lithium salts.
10. Batterie selon la revendication 9, caractérisée en ce que ledit ou lesdits plusieurs sels de lithium sont choisis parmi le bis [(trifluorométhyl)sulfonyl]imide de lithium (LiN(CF3 S 02)2) , le trifluorométhane sulfonate de lithium (LiCF3 S03), le bis(oxalato)borate de lithium (LiBOB), le difluoro(oxolato) borate de lithium (LiDFOB), le bis(perfluoroéthylsulfonyl)imide de lithium (LiN(CF3CF2S 02)2), LiC104, LiAsF6, LiPF6, LiBF4, Lil, LiCH3 S03 , LiB(C204)2, LÏRF S O S RF, LiN(RFS 02)2, LiC(RFS02)3 , RF étant un groupement choisi parmi un atome de fluor et un groupement perfluoroalkyle comportant entre un et huit atomes de carbone. 10. Battery according to claim 9, characterized in that said one or more lithium salts are chosen from lithium bis [(trifluoromethyl) sulfonyl] imide (LiN (CF 3 S 0 2 ) 2 ), lithium trifluoromethanesulfonate. (LiCF 3 S0 3), bis (oxalato) lithium borate (LiBOB), difluoro (oxolato) lithium borate (LiDFOB), bis (perfluoroéthylsulfonyl) lithium imide (LiN (CF 3 CF 2 S 0 2) 2), LiC10 4, LiAsF 6, LiPF 6, LiBF 4, Lil, LiCH 3 S0 3, LiB (C 2 0 4) 2, LiR F SOSR F, LiN (R F S 0 2) 2, liC (R F S0 2 ) 3 , R F being a group selected from a fluorine atom and a perfluoroalkyl group having between one and eight carbon atoms.
1 1 . Batterie selon l 'une quelconque des revendications précédentes, caractérisée en ce que ledit électrolyte comprend un ou plusieurs solvants .  1 1. Battery according to any one of the preceding claims, characterized in that said electrolyte comprises one or more solvents.
12. Batterie selon la revendication 1 1 , caractérisée en que ledit ou lesdits p lusieurs so lvants sont choisis parmi les so lvants polaires aprotiques, de préférence, le carbonate d' éthylène, le carbonate de propylène, le diméthylcarbonate, le diéthylcarbonate et le méthyléthylcarbonate.  12. Battery according to claim 1 1, characterized in that said one or more solvents are selected from aprotic polar solvents, preferably ethylene carbonate, propylene carbonate, dimethylcarbonate, diethylcarbonate and methylethylcarbonate. .
13. Procédé de préparation d'une batterie Li-ion telle que définie à l 'une quelconque des revendications précédentes, caractérisé en ce que ledit procédé comprend les étapes suivantes :  13. A method for preparing a Li-ion battery as defined in any one of the preceding claims, characterized in that said method comprises the following steps:
- fabrication d'une cellule, comprenant les étapes suivantes : préparation d'une première électrode par dépôt d'une masse donnée en un matériau pour électrode négative à base de graphite, sur un collecteur de courant, préparation d 'une seconde électrode par dépôt d'une masse adaptée, de telle manière que l ' équation ( 1 ) telle que définie ci-après : dans laquelle Q~ r ev désigne la capacité réversible surfacique de l ' électrode négative (mAh/cm2) ; - manufacture of a cell, comprising the following steps: preparing a first electrode by depositing a given mass of a graphite - based negative electrode material on a current collector, preparing a second electrode by depositing a suitable mass, such that the equation (1) as defined below: where Q ~ re v denotes the reversible surface capacity of the negative electrode (mAh / cm 2 );
Q+ rev désigne la capacité réversible surfacique de l ' électrode positive (mAh/cm2) ; Q + rev is the reversible surface capacity of the positive electrode (mAh / cm 2 );
L" désigne la masse surfacique de matériau actif pour l ' électrode négative (mg/cm2) ; L " denotes the density of active material for the negative electrode (mg / cm 2 );
L+ désigne la masse surfacique de matériau actif pour l ' électrode positive (mg/cm2) ; L + denotes the density of active material for the positive electrode (mg / cm 2 );
Q rev . sp e désigne la capacité réversible spécifique de l ' électrode négative (mAh/mg) ;  Q rev. sp e denotes the specific reversible capacity of the negative electrode (mAh / mg);
Q rev . sp e désigne la capacité réversible spécifique de l ' électrode positive (mAh/mg),  Q rev. sp e denotes the specific reversible capacitance of the positive electrode (mAh / mg),
soit respectée pour un ratio N/P = 1 , en un matériau pour électrode positive riche en lithium tel que défini ci-avant, sur un co llecteur de courant, sur un co llecteur de courant,  is respected for a ratio N / P = 1, a material for positive electrode rich in lithium as defined above, on a co-current sensor, on a co-current,
les deux étapes de préparation desdites première et seconde électrodes étant intervertibles,  the two steps of preparing said first and second electrodes being intervertible,
- empilement de la première électrode, de la seconde électrode telles que préparées ci-dessus, et d'un séparateur, situé entre les deux électrodes,  stacking the first electrode, the second electrode as prepared above, and a separator, located between the two electrodes,
- imprégnation du séparateur par un électrolyte,  impregnation of the separator with an electrolyte,
- assemblage d'une ou plusieurs cellule(s) telle(s) que précédemment fabriquée(s) . - assembly of one or more cell (s) such as previously manufactured (s).
14. Procédé de cyclage d'une batterie Li-ion telle que définie à l 'une quelconque des revendications 1 à 12 , caractérisé en ce que ledit procédé comprend les étapes suivantes : 14. A method of cycling a Li-ion battery as defined in any one of claims 1 to 12, characterized in that said method comprises the following steps:
- un premier cycle d' activation entre une tension Tsup strictement supérieure à 4,40 V, de préférence comprise entre 4,40 V borne exclue et 4,60 V, et une tension Tlnf comprise entre 1 ,60 et 2,50 V, de préférence égale à 2 V, a first activation cycle between a voltage T sup strictly greater than 4.40 V, preferably between 4.40 V excluded and 4.60 V, and a voltage T lnf between 1.60 and 2.50. V, preferably equal to 2 V,
- les cycles de charge et de décharge suivants à des tensions comprises entre une tension Tsup comprise entre 4,30 et 4,43 V, de préférence égale à 4,40 V, et une tension Tlnf comprise entre 1 ,60 et 2,50 V, de préférence égale à 2,30 V ; the following charging and discharging cycles at voltages lying between a voltage T sup of between 4.30 and 4.43 V, preferably equal to 4.40 V, and a voltage T lnf of between 1.60 and 2.degree. , 50 V, preferably equal to 2.30 V;
les cycles s ' effectuant à une capacité comprise entre C/20 et C, C désignant la capacité de la batterie Li-ion. the cycles being carried out at a capacity of between C / 20 and C, C denoting the capacity of the Li-ion battery.
15. Procédé selon la revendication 14, caractérisé en ce que ledit premier cycle d' activation s ' effectue à une capacité de C/ 1 0.  15. The method of claim 14, characterized in that said first activation cycle is carried out at a capacity of C / 10.
16. Procédé selon la revendication 14 ou 15 , caractérisé en ce que lesdits cycles de charge et de décharge suivants s ' effectuent à une capacité de C/2.  16. The method of claim 14 or 15, characterized in that said subsequent charge and discharge cycles are performed at a capacity of C / 2.
EP15706904.8A 2014-02-11 2015-02-10 Lithium-ion battery comprising a lithium-rich cathode and a graphite-based anode Withdrawn EP3105805A1 (en)

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FR1451054A FR3017489B1 (en) 2014-02-11 2014-02-11 LITHIUM ION BATTERY COMPRISING A LITHIUM RICH CATHODE AND A GRAPHITE-BASED ANODE
PCT/FR2015/050313 WO2015121574A1 (en) 2014-02-11 2015-02-10 Lithium-ion battery comprising a lithium-rich cathode and a graphite-based anode

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CN105993089A (en) 2016-10-05
WO2015121574A1 (en) 2015-08-20
US20160351948A1 (en) 2016-12-01
FR3017489A1 (en) 2015-08-14

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