Classifications

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  • 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
  • H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
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  • C01G45/12—Manganates manganites or permanganates
  • C01G45/1221—Manganates or manganites with a manganese oxidation state of Mn(III), Mn(IV) or mixtures thereof
  • C01G45/1228—Manganates or manganites with a manganese oxidation state of Mn(III), Mn(IV) or mixtures thereof of the type [MnO2]n-, e.g. LiMnO2, Li[MxMn1-x]O2
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  • C01G45/1221—Manganates or manganites with a manganese oxidation state of Mn(III), Mn(IV) or mixtures thereof
  • C01G45/1242—Manganates or manganites with a manganese oxidation state of Mn(III), Mn(IV) or mixtures thereof of the type [Mn2O4]-, e.g. LiMn2O4, Li[MxMn2-x]O4
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  • C01G51/40—Cobaltates
  • C01G51/42—Cobaltates containing alkali metals, e.g. LiCoO2
  • C01G51/44—Cobaltates containing alkali metals, e.g. LiCoO2 containing manganese
  • C01G51/50—Cobaltates containing alkali metals, e.g. LiCoO2 containing manganese of the type [MnO2]n-, e.g. Li(CoxMn1-x)O2, Li(MyCoxMn1-x-y)O2
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  • C01G51/00—Compounds of cobalt
  • C01G51/40—Cobaltates
  • C01G51/42—Cobaltates containing alkali metals, e.g. LiCoO2
  • C01G51/44—Cobaltates containing alkali metals, e.g. LiCoO2 containing manganese
  • C01G51/54—Cobaltates containing alkali metals, e.g. LiCoO2 containing manganese of the type [Mn2O4]-, e.g. Li(CoxMn2-x)04, Li(MyCoxMn2-x-y)O4
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  • C01G53/00—Compounds of nickel
  • C01G53/40—Nickelates
  • C01G53/42—Nickelates containing alkali metals, e.g. LiNiO2
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  • 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
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  • C01G53/40—Nickelates
  • C01G53/42—Nickelates containing alkali metals, e.g. LiNiO2
  • C01G53/44—Nickelates containing alkali metals, e.g. LiNiO2 containing manganese
  • C01G53/54—Nickelates containing alkali metals, e.g. LiNiO2 containing manganese of the type [Mn2O4]-, e.g. Li(NixMn2-x)O4, Li(MyNixMn2-x-y)O4
• • H—ELECTRICITY
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  • H01M4/36—Selection of substances as active materials, active masses, active liquids
  • H01M4/362—Composites
  • H01M4/366—Composites as layered products
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  • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
  • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
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  • 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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  • 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
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  • C01P2004/80—Particles consisting of a mixture of two or more inorganic phases
  • C01P2004/82—Particles consisting of a mixture of two or more inorganic phases two phases having the same anion, e.g. both oxidic phases
  • C01P2004/84—Particles consisting of a mixture of two or more inorganic phases two phases having the same anion, e.g. both oxidic phases one phase coated with the other
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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
  • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• • 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

Definitions

• the present invention relates to a process for preparing particles for use as active materials in a composite electrode for lithium batteries, which are coated with at least one layer of oxide, preferably a metal oxide layer, covering only the areas that are likely to be more reactive with a LiPF 6 lithium hexafluorophosphate electrolyte.
• Lithium batteries, or lithium accumulators occupy an increasingly important place in the market for the storage of electrical energy. Indeed, their current performance, particularly in the storage of electrical energy, far exceeds older technologies based on nickel batteries such as NiMH nickel metal hydride batteries or nickel cadmium NiCd batteries.
• lithium-ion batteries are particularly interesting rechargeable batteries because they can be advantageously used as a source of energy in portable electronic devices such as mobile phones and laptops, especially because of their low cost of ownership. This has been reduced by three in ten years, or in the automotive field, particularly electric cars, which requires a longer service life, higher electrochemical performances and a higher level of safety.
• lithium - ion batteries include a positive electrode, originally formed with a lamellar type oxide such as lithiated cobalt dioxide L1COO 2 as an active material, a negative electrode, initially made of carbonaceous materials such as graphite and an electrolyte impregnated in a porous separator and generally consisting of a mixture of carbonates and a lithium salt, in particular lithium hexafluorophosphate LiPF 6 .
• a positive electrode originally formed with a lamellar type oxide such as lithiated cobalt dioxide L1COO 2 as an active material
• a negative electrode initially made of carbonaceous materials such as graphite and an electrolyte impregnated in a porous separator and generally consisting of a mixture of carbonates and a lithium salt, in particular lithium hexafluorophosphate LiPF 6 .
• the carbonaceous materials coke, natural and artificial graphite, mesoporous carbon microspheres (MCMB), ...), lithium titanates of type Li 4 Ti 5 0 i 2 or even materials capable of forming an alloy with lithium such as silicon, tin or aluminum. Since each type of material is limited by its intrinsic properties, lithium accumulators with different specificities are obtained. For example, electrochemical systems having high charge or discharge power can be obtained for low storage energies or vice versa. Similarly, some materials can make a gain on the cost or safety of accumulators, or on their longevity or ability to recharge quickly.
• spinel materials of LiNi x Mn 2 -x0 4 type has proved advantageous for the manufacture of positive electrodes because these materials have a low cost price, due to the abundance of manganese, and have a high high operating potential on the order of 4.7V vs. Li + / Li which saves about 1 volt compared to conventional electrochemical systems using materials such as lithiated cobalt dioxide LiCo0 2 .
• the storage specific energy increases from 540 Wh.kg " for a system comprising a positive electrode using LiCo0 2 lithium cobalt dioxide at 700 Wh.kg " 1 for a system whose positive electrode is made from materials spinels.
• Systems using spinel materials of LiNi x Mn 2 - x 0 4 type thus have a certain number of advantages and make it possible in parallel to reach high powers of charge and discharge.
• the electrodes made from spinel materials of LiNi x Mn 2 - x 0 4 type have the disadvantage of having a reduced lifetime during (s) galvanostatic cycling (s), that is to say during the cycles comprising charging and discharging the electrochemical cell, as the cycling temperature increased.
• s galvanostatic cycling
• Such a limitation of the life of this type of electrode is due in particular to the degradation of the electrolyte during the operation of the accumulator.
• the lithium hexafluorophosphate LiPF 6 is degraded giving rise to the appearance of lithium fluoride LiF and pentafluorophosphate PF 5 according to the following mechanism: LiPF 6 - ⁇ LiF + PF 5
• pentafluorophosphate in the electrolyte then contributes, in the presence of water molecules, to generate HF hydrofluoric acid and OPF 3 trifluorophosphate according to the following reaction:
• the presence of hydrofluoric acid in the electrolyte therefore tends to favor and increase the dissolution rate of the manganese within the electrolyte, thus causing degradation of the electrode during galvanostatic cycling.
• the reaction between the electrolyte and the LiNi x Mn 2 - x 04 spinel materials leads to the formation of a passivation layer at the level of the grain surface of active materials which causes a decrease in their electrochemical performance.
• the metal oxides that can be used as a coating include alumina A1 2 0 3 , zirconium dioxide Zr0 2 or tin dioxide Sn0 2 .
• Coatings based on aluminum trifluoride A1F 3 , or more generally based on metal halides, may also be grafted onto the surface of the active materials.
• Phosphates such as AlP0 4 aluminum orthophosphate and BPO 4 boron phosphate can also be used as a coating.
• Such coatings are described in particular in patent applications WO 201 1/03 1544, WO 2006/1 09930 and US 201 1/01 1298.
• Coatings based on oxides or metal fluorides can be made from a so-gel process, a co-precipitation process as well as by means of chemical vapor deposition (CVD) or a physical vapor deposition (PVD).
• CVD chemical vapor deposition
• PVD physical vapor deposition
• Coating of the active materials carried out by means of co-precipitation is generally carried out in an aqueous solvent, in which a metal salt has been dissolved.
• the particles to be coated are then dispersed in the medium and the pH of the solution is modified by addition of an acid or a base so that the salt precipitates in the form of a metal oxide on the surface of the particles to be coated.
• the solvent is then evaporated and the recovered coated particles are annealed at temperatures of several hundred degrees, ranging from 250 to 800 ° C, for several hours.
• the annealing may be carried out under air for particles coated with a metal oxide and under an inert atmosphere for particles coated with a metal fluoride.
• coatings made from metal halides can also be obtained by means of a co-precipitation method by dispersing in an aqueous solvent an NH 4 X ammonium halide salt, with X corresponding to a halogen atom.
• the coating of active materials from a sol-gel process is generally carried out using metal alkoxides as precursors.
• the metal alkoxides are thus dissolved in a non-aqueous solvent, preferably an alcohol, so as to obtain a solution and the particles to be coated are then dispersed in said solution.
• the solution is mixed for several hours at a temperature of 80 ° C while allowing the solvent to evaporate slowly.
• the particles are then recovered and annealed at temperatures which may be of the order of 400 ° C. for five hours in air.
• a zirconium precursor solution is prepared from isopropanol, zirconium tetrapropoxide (Zr (OC 3 H 7 ) 4 ), acetylacetone and water in molar ratios of 170/1 / 1.5 / 6.
• the particles to be coated (LiNii / 3Mni / 3 Co / 302) are then added and the resulting solution is stirred under ultrasound for 30 minutes at 40 ° C. The solvent is then evaporated under vacuum.
• the volume of the precursor solution, in which the particles of LiNiO.4Mn1.6O4 are dispersed, is calculated so as to obtain a final amount of ZrCl.sub.2 of between 0.35 and 3.5 mol% .
• the powders obtained are then heated to 750.degree. ° C for two hours under oxygen.
• the particles (Linii / 3 Mni / Coi 3/3 02) obtained as a result of this process comprise at their surface a deposit of particles of zirconium dioxide (Zr0 2 ) and not a layer consisting of zirconium dioxide.
• this process does not lead to the production of a layer of zirconium dioxide covering the particles and, therefore, does not effectively protect the active materials during galavanostatic cycling.
• a ZrO 2 type coating by using a ZrCl 4 metal salt precursor (HM Wu et al J. Power Sources 195, 2010, 2909).
• This salt is dissolved in ether and the particles to be coated are added.
• the ZrCl 4 particles gradually form inert ZrO 2 particles in the ether which cover the surface of the particles to be coated.
• the remaining solvent is then evaporated under vacuum and the powder is calcined at 400 ° C for six hours.
• particles are also obtained which comprise at their surface a deposit of zirconium dioxide particles (Zr0 2 ) and not a layer consisting of zirconium dioxide (Zr0 2 ).
• the methods used do not yet make it possible to lead to particles, intended to be used as active materials in a composite electrode of a lithium battery, which are suitably coated with oxides of metals, generally of oxides, and whose reactivity with a lithium hexafluorophosphate LiPF 6 electrolyte is satisfactorily lowered to a stable electrochemical system.
• the object of the invention is in particular to provide a method for driving particles coated with a layer consisting of oxide, in particular metal oxide, which are intended to be used as that active materials in a composite electrode of a lithium battery in order to decrease their reactivity during galvanostatic cycling, including at high temperature, and to obtain a better electrochemical stability.
• oxide in particular metal oxide
• the process according to the invention therefore consists in particular in partially coating the particles as defined above in order to cover the zones which are the most reactive with respect to a lithium hexafluorophosphate electrolyte. LiPF 6 while keeping free the least reactive areas vis-à-vis this electrolyte.
• the particles are covered locally on the most reactive zones with respect to the electrolyte by layers of oxide, in particular of metal oxide, which are uniform and dense.
• the particles obtained as a result of this process are therefore less subject to any chemical and / or electrochemical reactions.
• the process therefore leads to the preparation of particles of which only the most reactive parts are protected from the electrolyte, which makes it possible to greatly reduce the reactivity of said particles at a high operating potential.
• the fact of having particles having areas which are not covered by an oxide layer, that is to say of free parts makes it possible to promote the insertion and circulation of the particles. lithium ions more efficiently than if they had been covered.
• the partial coating of the particles serving as active materials within a composite electrode in a lithium battery promotes the circulation of lithium ions during the charging and discharging of the electrochemical cell.
• the particles obtained with the process according to the invention do not cause a loss of discharge capacity since they lead to an improvement the kinetics of insertion of lithium ions. Indeed, the uniform coverage of the particles over their entire surface tends to slow down the flow of lithium ions within the electrochemical cell.
• the process according to the present invention has the advantage of being more economical than a chemical or physical vapor deposition process.
• the method thus implemented thus makes it possible to prepare particles which are suitably coated with a layer of oxide, preferably of metal oxide, so as to effectively reduce their reactivity with respect to an electrolyte of a battery. lithium.
• the present invention therefore has especially obj and a method, especially an anhydrous process in which no addition of water is made, for the preparation of particles, intended to be used as active materials in a composite electrode of a lithium battery, comprising at least one zone (a) and at least one zone (b), said zone (a) being more likely to react with a lithium hexafluorophosphate electrolyte LiPF 6 than said zone (b), said method comprising:
• X is a halogen atom such as fluorine or chlorine
• A is selected from transition metals and elements of columns IIIA and IVA of the periodic table of elements,
• R 1 represents a linear or branched C 1 -C 5 alkyl radical
• R 2 represents a single bond or a C 1 -C 5 linear or branched alkyl radical
• R 3 represents a linear or branched C 1 -C 5 alkyl radical
• step (iii) a step of mixing the anhydrous dispersion obtained in step (i) and the anhydrous composition prepared in step (ii) so as to obtain particles of which said zone (a) is covered on the surface with at least a layer of oxide of the formula R 1 r (R 2 X) x a w 0 3 _ w r, w and x varying from 0 to 2, v varying from 1 to 2 and a, R 1 and R 2 having the same definitions as those indicated above, and said zone (b) is not covered on the surface by said oxide layer.
• the process thus makes it possible to obtain particles coated locally with an oxide layer, preferably a metal oxide layer.
• Steps (i) and (ii) of the process according to the invention advantageously employ anhydrous compositions.
• the presence of water in a conventional process for effecting a coating at the surface of the particles does not favor the formation of a coating but rather the formation of a deposit of particles adsorbed on the surface of said particles.
• the process according to the present invention is therefore an anhydrous process, in which no addition of water is carried out in any of steps i) to iii).
• the anhydrous nature of the process according to the invention allows the maintenance of the precursors during the recovery of the particle and, ultimately, a localized recovery on areas of high reactivity.
• zone (a) of the particles obtained according to the process of the invention is or are covered by a layer of oxide of the formula R 1 r (R 2 X) x A v 03- w uniform and dense and not by particles of oxide of the formula R 1 r (R 2 X) x A v 03- w.
• anhydrous composition in the sense of the present invention a composition having a water content of less than 2%, preferably less than 1% by weight relative to the total weight of the composition. It should be noted that the presence of water in the anhydrous composition can come from traces of water which are adsorbed by the raw materials used in the production of the anhydrous composition or the controlled addition of water in the composition.
• the anhydrous composition contains less than 100 ppm of water, preferably less than 30 ppm of water. More preferably, the particles to be coated are dispersed in a composition free of water.
• the process comprises a step (i) of dispersing the particles as defined above in an anhydrous composition.
• step (i) of the process according to the present invention consists in preparing an anhydrous dispersion of the particles as defined above.
• the dispersion prepared during step (i) may be in the form of a stable suspension of particles having a size ranging from 10 nm to 50 ⁇ m, preferably ranging from 100 to 5000 nanometers, and more preferably ranging from 200 nm. at 2000 nanometers in an anhydrous composition.
• the dispersion prepared during step (i) is a colloidal suspension of particles having a size ranging from 200 nm to 5000 nanometers in an anhydrous composition.
• the size of an individual particle corresponds to the maximum dimension that can be measured between two diametrically opposed points of an individual particle.
• the size can be determined by transmission electron microscopy or from the measurement of the specific surface area by the BET method or from a laser granulometry.
• the average number size of the particles present in the anhydrous composition can vary from 10 to 50000 nanometers, preferably from 200 to 5000 nanometers.
• the dispersion is preferably prepared at ambient temperature, ie at a temperature which may vary from 20 to 25 ° C., under a controlled atmosphere, in particular for a time ranging from 10 minutes to 7 days.
• the particles dispersed in the anhydrous composition during step (i) are particles of formula LiM 2 O 4 in which M '"is selected from nickel, manganese and mixtures thereof. in particular, M "'is chosen from mixtures of nickel and manganese.
• the particles dispersed in the anhydrous composition during step (i) are particles of the formula LiNi0.5 x Mni i 5 + x 04 in which x varies from 0 to 0.1.
• step (i) consists of preparing a suspension of particles of formula LiNiO 4 Mn Li 4 O 4 having a size ranging from 200 to 5000 nanometers.
• the particles are present in the anhydrous dispersion prepared during step (i) in a concentration ranging from 0.05 to 10% by weight, preferably ranging from 3 to 5% by weight.
• the anhydrous composition used in step (i) of the process according to the invention may comprise at least one organic solvent chosen from alkanes such as cyclohexane or (C 5 -C 8) alkanes, alcohols, methyl-2-pyrrolidone, dimethylformamide, ethers, glycol, dimethylsilicone and mixtures thereof.
• alkanes such as cyclohexane or (C 5 -C 8) alkanes, alcohols, methyl-2-pyrrolidone, dimethylformamide, ethers, glycol, dimethylsilicone and mixtures thereof.
• the organic solvent is chosen from alcohols, in particular C 2 -C 5 alcohols, in particular ethanol, isopropanol and 1-propanol.
• the organic solvent is isopropanol.
• the particles of formula LiNiO 4 Mn 14 O 4 are dispersed in an organic solvent chosen from alcohols, in particular isopropanol.
• the process comprises a step (ii) of preparing an anhydrous composition comprising at least one alkoxide compound of formula R 1 t (R 2 X) u A (OR 3 ) z - (t + u) such than previously defined.
• step (ii) of the process according to the invention consists in preparing an anhydrous solution comprising at least one alkoxide compound of formula R 1 t (R 2 X) u A (OR 3 ) z - (t + u ) as defined above.
• the alkoxide compounds can be completely dissolved in the anhydrous composition during step (ii) to obtain a clear solution.
• A is chosen from titanium, zirconium, iron, aluminum, zinc, indium, copper, silicon and tin, yttrium, boron, chromium, manganese, iron, vanadium, zirconium and mixtures thereof.
• A is chosen from transition metals, in particular zirconium, the elements of column IIIA, in particular aluminum, and the elements of column IVA, in particular silicon.
• A is chosen from zirconium, aluminum and silicon, in particular zirconium.
• R 1 t (R 2 X) u A (OR 3 ) z - (t + u) is equal to 0, u is equal to 0 and z is equal to 4.
• z- (t + u) is non-zero.
• R 3 represents a hydrocarbon radical C 2 -C 4 , preferably C 2 -C 3 , more particularly C 3.
• the alkoxide compounds are chosen from the compounds Si (OC 2 H 5 ) 4 , Zr (OC 3 H 7 ) 4 and Al (OC 3 H 7 ) 3 , in particular Zr (OC 3 H 7) ) 4 .
• the alkoxy compounds may be present in the anhydrous composition prepared in step (ii) in a concentration ranging from 1 to 10 ⁇ 5 mol.L 1 , preferably in a concentration ranging from 10 ⁇ 4 to 10 ⁇ 2 mol .L "1 .
• the anhydrous composition prepared in step (ii) may comprise at least one organic solvent chosen from alcohols, n-methyl-2-pyrrolidone, dimethylformamide, ethers, glycol, dimethylsilicone and mixtures thereof.
• the organic solvent is chosen from alcohols, in particular isopropanol.
• the anhydrous composition prepared in step (ii) may also comprise at least one chelating agent.
• the chelating agent makes it possible to control the rate of hydrolysis and condensation of the alkoxide precursor so as to prevent the formation of oxide particles.
• the chelating agent is chosen from saturated and unsaturated ⁇ -diketones (especially acetylacetone or 3-allylpentane-2,4-dione) and ⁇ -ketoesters (such as methacryloxyethylacetoacetate, allylacetoacetate or ethyelacetate acetate).
• saturated and unsaturated ⁇ -diketones especially acetylacetone or 3-allylpentane-2,4-dione
• ⁇ -ketoesters such as methacryloxyethylacetoacetate, allylacetoacetate or ethyelacetate acetate.
• the anhydrous composition comprises at least one chelating agent such as acetylacetate.
• the molar ratio between the chelating agent and the alkoxide compound may vary from 0.01 to 6, preferably from 0.1 to 4, more preferably from 0.5 to 2.
• the anhydrous composition prepared during step (ii) may comprise isopropanol and acetylacetate.
• the molar ratio of the alkoxide compound / specific surface of the particles to be coated may vary from 1 to 500 ⁇ ⁇ "2 , preferably from 5 to 250 ⁇ . ⁇ 2 .
• composition prepared in step (ii) may further comprise at least one catalyst.
• the catalyst may be chosen from organic acids, dibutyltindilaurate (DBTL) and ammonia.
• DBTL dibutyltindilaurate
• ammonia ammonia
• the catalyst is chosen from organic acids, especially formic acid, acetic acid, citric acid, acrylic acid, methacrylic acid, methacrylamidosalicylic acid, cinnamic acid, sorbic acid, 2-acrylamido-2-methylpropanesulfonic acid, itaconic anhydride and mixtures thereof.
• step (i) consists in preparing a colloidal suspension of particles of the formula LiNi 4Mni i6 04 in an anhydrous composition and step (ii) comprises preparing an anhydrous composition comprising at least one compound alkoxide of formula R 1 t (R 2 X) u A (OR 3 ) z - (t + u), in which t is equal to 0, u is equal to 0, z is equal to 4, A is chosen from zirconium, silicon and aluminum and R 3 represents a C2-C4 alkyl radical.
• the process comprises a step of mixing the dispersion obtained in step (i) and the anhydrous composition prepared in step (ii) so as to obtain particles of which said zone (a) is covered. on the surface by at least an oxide layer of the formula R 1 r (R 2 X) x A v 03- w , in which r, w and x vary from 0 to 2, v varies from 1 to 2 and R 1 and R 2 have the meanings previously indicated and said zone (b) is not covered on the surface by an oxide layer of formula
• the reaction occurs especially at the surface of the particles between the precursor and the surface to be protected to lead to the formation of a covalent bond between the surface of the particle and the oxide.
• the presence of the hydroxy groups at the surface of the particles will orient the surface reaction between the precursor and the areas of the particles to be protected so as to form the oxide layer.
• the anhydrous composition prepared during step (ii) is added to the dispersion of particles prepared during step (i), more particularly the anhydrous composition prepared during step (ii) is added dropwise to the dispersion prepared during step (i) for a reaction time ranging from 30 minutes to 10 hours, preferably about 2 hours and preferably at room temperature (typically between 22 ° C and 5 ° C).
• the supernatant is removed and the particles obtained are rinsed with an organic solvent.
• step (iii) The particles obtained during step (iii) are then recovered and dried at a temperature ranging from 40 to 130 ° C. for a time ranging from 1 to 48 hours.
• the particles are annealed at a temperature ranging from 250 to 800 ° C for a time ranging from 1 to 48 hours.
• the particles obtained following the method according to the present invention therefore have a layer of oxide of the formula R 1 r (R 2 X) x A w 0 -w 3 at one or more areas (a) and are free from said layer at one or more zones (b), the or zones (a) being more likely to react with lithium hexafluorophosphate electrolyte LiPF 6 than said at least one zone (b).
• A is selected from titanium, zirconium, iron, aluminum, zinc, indium, copper, silicon and tin.
• A is chosen from transition metals, in particular zirconium, the elements of column IIIA, in particular aluminum, and the elements of column IVA, in particular silicon.
• A is chosen from zirconium, aluminum and silicon, in particular zirconium.
• the oxide layer is a layer of formula Si0 2 , Zr0 2 , Sn0 2 , Al 2 O 3 , Ti0 2 , Ce0 2 .
• the particle coverage rate may range from 5 to 95%, preferably ranges from 30 to 90% and even more preferably ranges from 50 to 80%.
• the area or areas (a) of the particles is or are covered by a layer of the formula R 1 r (R 2 X) x A w 0 3 _ w having a thickness ranging preferably from 0.25 to 10 nanometers, more preferred ranging from 0.5 to 4 nanometers.
• FIG. 1 represents an image obtained by scanning microscopy with a lateral resolution of 100 nanometers on the most reactive zones of the particles of which are covered by a layer of zirconium dioxide,
• FIG. 2 represents an image obtained by scanning microscopy with a lateral resolution of 50 nanometers on the zones the most reactive particles of LiNiO 4 Mni i6 0 4 which are covered by a zirconium dioxide layer,
• FIG. 3 shows an image obtained by scanning microscopy with a lateral resolution of 500 nanometers on the most reactive areas of the particles of LiNi 0 4 4 Mni i6 which are covered by a deposit of zirconium dioxide particles,
• FIG. 4 shows an image obtained by scanning microscopy with a lateral resolution of 50 nanometers on the most reactive areas of the particles of LiNi 0 4 4 Mni i6 which are covered by a deposit of zirconium dioxide particles,
• FIG. 5 represents an electrochemical cell of the "button cell” type mounted in a glove box
• FIG. 6 represents a graph illustrating the discharge capacity of an electrochemical cell as a function of the number of cycles for a spinel active material for which the reactive zones are covered by an oxide layer and for an uncoated active material
• FIG. 7 represents a graph illustrating the evolution of the irreversible capacity as a function of the number of cycles for a spinel active material for which the reactive zones are covered by an oxide layer and for an uncoated active material.
• a solution of zirconium propoxide (Zr (OPr) 4 ) at 10 -1 mol / L in a glove box is prepared from a commercial solution containing 70% by weight of zirconium propoxide. 2.34 grams of the commercial solution that is added to a 50 mL volumetric flask. It is made up with anhydrous isopropanol to the mark and the solution is stirred for 48 hours in order to obtain a transparent solution.
• a solution of zirconium propoxide (Zr (OPr) 4 ) at 10 -1 mol / L containing acetylacetone (AcAc) in an acetylacetone / zirconium propoxide molar ratio 0.25 from a commercial solution is prepared at 70% by weight of zirconium propoxide.
• a solution of zirconium propoxide (Zr (OPr) 4 ) at 10 -1 mol / L containing acetylacetone (AcAc) in an acetylacetone / zirconium propoxide molar ratio 0.5 from a commercial solution is prepared at 70% by weight of zirconium propoxide.
• a solution of zirconium propoxide (Zr (OPr) 4 ) at 10 -1 mol / L containing acetylacetone (AcAc) in an acetoacetone / zirconium propoxide molar ratio 0.75 from a commercial solution is prepared at 70% by weight of zirconium propoxide.
• a solution of zirconium propoxide (Zr (OPr) 4 ) at 10 -1 mol / L containing acetylacetone (AcAc) in an acetylacetone / zirconiumpropoxide molar ratio 1 from a commercial solution of 70 is prepared. % by weight of zirconium propoxide.
• a solution of zirconium propoxide (Zr (OPr) 4 ) at 10 -1 mol / L containing acetylacetone (AcAc) in an acetylacetone / zirconium propoxide molar ratio 1.5 from a commercial solution is prepared at 70% by weight of zirconium propoxide.
• Example 1 Preparation of particles LiNi Mni 4, 6 0 4 partially coated is prepared LiNi material Mni i6 4 0 4 according to the method described in patent application WO2007 / 023235.
• LiNi0 4 Mni i6 0 4 material 1 gram of LiNi0 4 Mni i6 0 4 material is dispersed in 32 ml of anhydrous isopropanol under a controlled atmosphere (Ar).
• the dispersion of the material is carried out by magnetic stirring for two hours, then using a vacuum disperser sold under the name dispermat ® for 10 minutes at 800 revolutions per minute. The agitation of the magnetized bar is then maintained to maintain good dispersion throughout the experiment.
• a solution is prepared from the solution described in Example 3. To do this, 1 ml of the stock solution illustrated in Example 3 (Part I) is taken and added to a 100 ml volumetric flask. and the flask is filled to the mark with anhydrous isopropanol in a glove box.
• This solution is added dropwise to the particle dispersion previously prepared.
• the addition of the 100 ml is carried out in 30 minutes with vigorous stirring with the magnetized bar. After 2 hours of reaction between the dispersion and the solution, the mixture is centrifuged at a speed of 4000 rpm for 3 minutes. The supernatant is removed and the powder is rinsed with a large excess of isopropanol. The powder is then recovered and dried in an oven at 100 ° C., under air, for 3 hours.
• the powder is annealed at 500 ° C., under air, for 5 hours.
• Particles is obtained, called Zr0 2 -LiNio, 4Mni i6 04 having a zirconium dioxide Zr0 2 layer located on the most reactive zone of the particles according to Figures 1 and 2.
• FIG. 1 represents an image obtained by scanning electron microscopy with a lateral resolution of 100 nanometers of the LiNi0 4Mni i6 04 particles obtained according to the preparation method of Example 1 of Part II.
• Figure 1 shows a localized area (a) of LiNi particles 4Mni i6 04 which is covered by the layer of zirconium dioxide Zr0 2 and a region (b) not covered by the zirconium dioxide layer. Therefore, Figure 1 shows that the process results in a localized coating on the more reactive areas of the particles.
• Figure 2 shows an image obtained by scanning electron microscopy with a lateral resolution of 50 nanometers particles obtained in accordance with the process for the preparation of Example 1 of Part II.
• the material LiNiO 4Mni i6 04 is prepared according to the process described in the patent application WO2007 / 023235
• Dispersing 1 gram of material LiNi 4 Mni i6 04 in 32 ml of anhydrous isopropanol under a controlled atmosphere (Ar). The dispersion of the material is carried out by magnetic stirring for two hours, then with the aid of a vacuum disperser sold under the name dispermat® for 10 minutes at 800 revolutions per minute. The agitation of the magnetized bar is then maintained to maintain good dispersion throughout the experiment. 1 ml of water is added to the resulting dispersion which is then stirred for two hours.
• a solution is prepared from the solution described in Example 3. To do this, 1 ml of the stock solution illustrated in Example 3 is taken and added to a 100 ml volumetric flask, and the mixture is added. vial to the mark with anhydrous isopropanol in a glove box.
• the addition of the 100 ml is carried out in 30 minutes with vigorous stirring with the magnetized bar. After 2 hours of reaction between the dispersion and the solution, the mixture is centrifuged at a speed of 4000 rpm for 3 minutes. The supernatant is removed and the powder is rinsed with a large excess of isopropanol. The powder is then recovered and dried in an oven at 100 ° C., under air, for 3 hours.
• the powder is annealed at 500 ° C., under air, for 5 hours.
• Particles LiNi0 4 Mni i6 04 are obtained, the surface of which is covered by a deposit of zirconium dioxide particles Zr0 2 and not a layer of zirconium dioxide Zr0 2 located on the most reactive zones of the particles as it was possible to find in Example 1 of Part II does not involve the addition of water during the process.
• Figure 3 shows an image obtained by scanning electron microscopy with a lateral resolution of 500 nanometers of LiNi particles 4Mni i6 04 obtained according to the method of preparation of Example 2 of Part II.
• FIG 3 shows the surface of a LiNi particle 4Mni i6 04 which is covered by a deposit of zirconium dioxide Zr0 2 particles.
• FIG. 3 shows that a process identical to that of the invention using a composition containing water leads to particles whose surface is covered by a deposition of particles Zr0 2 and non-Zr0 2 layer.
• FIG. 4 shows an image obtained by scanning electron microscopy with a lateral resolution of 50 nanometers of particles obtained in accordance with the preparation method of Example 2 of Part II.
• LiNi particle 4Mni i6 04 which is covered by a deposit of zirconium dioxide Zr0 2 particles.
• LiNi0 4 Mni i6 0 4 material 1 gram of LiNi0 4 Mni i6 0 4 material is dispersed in 32 ml of anhydrous isopropanol under a controlled atmosphere (Ar).
• the dispersion of the material is carried out by magnetic stirring for two hours, then with the aid of a vacuum disperser sold under the name dispermat® for 10 minutes at 800 revolutions per minute. The agitation of the Magnetic bar is then maintained to maintain good dispersion throughout the experiment.
• a solution is prepared from the solution described in Example 3. To do this, 1 ml of the stock solution illustrated in Example 3 (Part I) is taken and added to a 100 ml volumetric flask. and the flask is filled to the mark with anhydrous isopropanol in a glove box.
• the powder is annealed at 500 ° C., under air, for 5 hours.
• Particles called Zr0 2 -LiNi0, 4Mni i6 04, are obtained having a ZrO 2 zirconium dioxide layer located on the most reactive zones of the particles.
• Example 1 of Part II The material obtained in Example 1 of Part II, that is to say the particles called Zr0 2 -LiNi0, 4Mni i6 04, is used for the preparation of a composite electrode (cathode) for lithium-ion batteries. .
• the ink is then deposited on an aluminum substrate using a doctor blade.
• the deposited ink thickness is 100 ⁇ before drying.
• the ink thus deposited is then dried in an oven at 55 ° C. under air for 12 hours.
• Circular pellets are then cut, with a diameter of 14 mm, which are press to 6.5 tons per cm 2 to ensure good cohesion of the composite electrode.
• a positive electrode (cathode) is prepared according to Example III.
• Li 4 Ti 5 0 i 2 pellets are used to constitute the negative electrode (anode). These electrodes are prepared similarly to the positive electrode and containing 82% by weight of Li 4 Ti 5 0 i 2, 6% of carbon fibers sold under the name Super P® carbon, 6% by weight of carbon fibers sold under the name Tenax® and 6% by weight of polyvinylidene fluoride.
• the performance of the coated materials will be evaluated via cells of the "button cell” type, such as the batteries sold under the name CR2032.
• the electrochemical cell mounted in a "button cell" manner in an Ar atmosphere in a glove box is shown in FIG.
• FIG. 5 represents the electrochemical cell mounted in the glove box which comprises a cover (3) and a bottom (10).
• the electrochemical cell comprises the negative electrode (6) ie. the anode prepared in accordance with Example 4.1 and the positive electrode (8), ie the cathode prepared according to Example III.
• the two electrodes (6) and (8) are separated by a separator (7) made of Celgard 2600 polyethylene, impregnated with 150 of an electrolyte composed of a mixture of carbonates (ethylene carbonate (EC) / propylene carbonate (PC ) / dimethylcarbonate (DMC) 1/1/3 by volume) and a lithium salt (LiPF 6 ) at a concentration of 1 mo l. L "1 .
• the electrochemical cell is crimped after adding a stainless steel wedge (5) and a spring (4) in order to maintain a constant pressure on the electrodes during the charge-discharge cycles of the drums.
• a seal (9) is disposed between the positive electrode (8) and the bottom of the glove box (10).
• Load and discharge tests are carried out at different speeds between C / 5 and 5C.
• a regime of C / n corresponds to a total discharge of the accumulator in n hours.
• a regime of 2C, ie C / 0.5 corresponds to a total discharge (respectively charge) of the accumulator in 0.5 hour.
• FIG. 6 shows the discharge measurements at different regimes and at medium temperature (55 ° C.) as a function of the number of cycles for a coated material prepared in accordance with Example 3 (curve Di [Zr0 2 -LNM]) and a material uncoated (D 2 curve [LNM]) at an operating potential between 3 and 5 volts.
• the coating covers the most reactive areas of the particles, the reactivity with the electrolyte is limited and thus the electrode / electrolyte interface is less disturbed, which improves the stability of the system over time.
• the coated active material resists better than the uncoated material, thus clearly demonstrating the protective properties of the coating at the most reactive regions of the spinel particles.
• the discharge capacity of the accumulator observed for the first four cycles is quite similar whether the material is coated or not, there is an irreversible discharge part in the capacity which is more important for the non-material. coated (3%) than for the coated material (2%). This combined with the fact that the loss of capacity observed as a function of the number of cycles is greater for the uncoated material than for the coated material shows that the coated material has a better stability than the bare material.
• Figure 7 shows the evolution of the irreversible capacity of ZrO 2 -LiNiO materials. 4 Mn 1 .6 O4 and LiNi. 4 Mn 1 .6 O4 uncoated depending on the number of cycles at a temperature of 25 ° C and an operating potential of between 2 and 3, 45 volts.
• the curve (C i) represents the evolution of the irreversible capacity of the materials ZrO2-LiNiO.4Mn1.6 O4 as a function of the number of cycles and the curve (C2) represents the evolution of the irreversible capacity of LiNiO.4Mn1.6O4 materials as a function of the number of cycles.
• Figure 7 shows that the ZrO 2 -LiNio.4Mn1.6O4 material to which the reactive zones are coated with the Zr0 2 layer has an irreversible capacity smaller than that of the uncoated material, in particular after 4 cycles at a C regime / 5. This shows that the coulombic efficiency is improved.

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• 2012
  • 2012-08-09 FR FR1257730A patent/FR2994510B1/fr not_active Expired - Fee Related
• 2013
  • 2013-07-31 JP JP2015525924A patent/JP2015530703A/ja active Pending
  • 2013-07-31 WO PCT/FR2013/051857 patent/WO2014023896A2/fr active Application Filing
  • 2013-07-31 CN CN201380052894.2A patent/CN104703919B/zh not_active Expired - Fee Related
  • 2013-07-31 US US14/420,459 patent/US20150295242A1/en not_active Abandoned
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