Classifications

• • 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
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B25/00—Phosphorus; Compounds thereof
  • C01B25/16—Oxyacids of phosphorus; Salts thereof
  • C01B25/26—Phosphates
  • C01B25/455—Phosphates containing halogen
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
  • C01D15/00—Lithium compounds
• • 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
• • 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
  • H01M10/0561—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of inorganic materials only
  • H01M10/0563—Liquid materials, e.g. for Li-SOCl2 cells
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M12/00—Hybrid cells; Manufacture thereof
  • H01M12/02—Details
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M2300/00—Electrolytes
  • H01M2300/0017—Non-aqueous electrolytes
  • H01M2300/002—Inorganic electrolyte
• • 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 method for the manufacture of L1PO 2 F 2 and to crystalline L1PO 2 F 2 .
• L1PO 2 F 2 is useful as electrolyte salt or additive for an electrolyte salt for lithium ion batteries.
• WO 2008/111367 discloses how to manufacture a mixture of LiPF 6 and L1PO 2 F 2 from a halide other than a fluoride, LiPF 6 and water. The resulting salt mixture, dissolved in aprotic solvents, is used as an electrolyte solution for lithium ion batteries.
• EP-A-2 061 115 describes, as state of the art at that time, the manufacture of L1PO 2 F 2 from P 2 O 3 F 4 and Li compounds, and, as invention, the manufacture of L1PO 2 F 2 from LiPF 6 and compounds with a Si-O-Si bond, e.g. siloxanes.
• Object of the present invention is to provide L1PO 2 F 2 in a technically feasible manner. Another object of t he present invention is to provide L1PO 2 F 2 which can easily be handled.
• L1PO 2 F 2 is manufactured by the reaction of P 4 O 10 with LiF.
• the resulting reaction mixture comprises L1PO 2 F 2 . It is assumed that L1 3 PO 4 is present in the reaction mixture as byproduct according to the reaction equation
• the molar ratio of LiF to P 4 O 10 is preferably equal to or greater than 5: 1. It is preferably equal to or lower than 10, more preferably, ⁇ 8.
• the reaction is performed in the absence of water or moisture.
• the reaction may be performed at least for a part of its duration in the presence of an inert gas ; dry nitrogen is very suitable, but other dry inert gases may be applied, too.
• the reaction can be performed in an autoclave or in other reactors. It is preferred to perform the reaction in apparatus made from steel or other materials resistant against corrosion, e.g. in reactors made of or clad with Monel metal.
• the lithium fluoride applied is preferably comminuted, e.g. milled to obtain a higher contact surface between phosphoric acid anhydride and LiF. It is preferred to mix the reactants thoroughly. For example, this can be performed, preferably in the presence of dry inert gas, e.g. nitrogen, in a dry box or in a mixer, e.g. a mixer with three dimensional flow.
• the reaction time is selected such that the desired degree of conversion is achieved. Often, a reaction time of 10 minutes to 5 hours gives good results.
• the reaction temperature is preferably equal to or higher than 225 °C, preferably equal to or higher than 250°C.
• the reaction temperature is preferably equal to or lower than 325°C, preferably equal to orlower than 300°C.
• a reactor can be applied with internal heating or external heating.
• the resulting reaction mixture is in solid form. If desired, it is
• the LiP0 2 F 2 formed can be isolated from the resulting reaction mixture, if desired. This can be achieved by dissolving it with solvents which preferentially dissolve LiP0 2 F 2 .
• Aprotic and protic organic and inorganic solvents are suitable, especially polar solvents.
• the preferred inorganic solvent is water.
• Organic protic or aprotic solvents can be used for the extraction, too.
• Suitable protic organic solvents are alcohols. Alcohols with one, two or three hydroxy groups in the molecule are preferred. Methanol, ethanol, n-propanol, i-propanol, glycol and glycerine are preferred alcohols. Glycol alkyl ethers, e.g. diglycol methyl ether, are also suitable. Also acetone, in its tautomeric form, can be considered as protic solvent.
• Another highly suitable solvent for LiP0 2 F 2 is dimethoxyethane. This solvent dissolves a great emount of LiP0 2 F 2 , but at most neglectable amounts of LiF.
• the aprotic organic solvent is selected from the group of dialkyl carbonates (which are linear) and alkylene carbonates (which are cyclic), and wherein the term "alkyl” denotes preferably CI to C4 alkyl, the term “alkylene” denotes preferably C2 to C7 alkylene groups, including a vinylidene group, wherein the alkylene group preferably comprises a bridge of 2 carbon atoms between the oxygen atoms of the -0-C(0)-0- group ; ketones, nitriles and formamides.
• Dimethyl formamide, carboxylic acid amides for example, ⁇ , ⁇ -dimethyl acetamide and ⁇ , ⁇ -diethyl acetamide, acetone, acetonitrile, linear dialkyl carbonates, e.g. dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, cyclic alkylene carbonates, e.g. ethylene carbonate, propylene carbonate, and vinylidene carbonate, are suitable solvents.
• linear dialkyl carbonates e.g. dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate
• cyclic alkylene carbonates e.g. ethylene carbonate, propylene carbonate, and vinylidene carbonate
• the pH of the water used for extraction, and of water-containing organic solvents applied for extraction, of the L1PO 2 F 2 formed in the reaction is selected such that undesired hydrolysis of L1PO 2 F 2 is prevented.
• the pH is equal to or lower than 7 to prevent hydrolysis. It is preferred to keep the pH at a value of equal to or lower than 7 during the contact of L1PO 2 F 2 formed with the water or the mixture of water and organic solvent or solvents.
• Mixtures of water and protic solvents can be applied for the isolation of L1PO 2 F 2 , for example, mixtures of water and alcohols with 1, 2 or 3 hydroxy groups, e.g., mixtures of water and methanol, ethanol, isopropanol, n-propanol, glycol, glycerine or diglycol.
• Mixtures of water and aprotic organic solvents, especially, polar aprotic solvents, can also be applied, for example, mixtures of water with one of the solvents mentioned above, e.g. with ethylene carbonate or propylene carbonate.
• mixtures which comprise water, one or more protic organic solvents and one or more aprotic organic solvents can be applied.
• mixtures containing water, an alcohol like methanol, ethanol or i-propanol, and a nitrile, for example, acetonitrile, or propylene carbonate can be applied.
• the content of water in these mixtures is preferably between 1 and 99 % by weight.
• the extraction may be performed in a known manner, for example, by stirring the reaction mixture with the solvent (extractant) directly in the reactor, or after removing the reaction mixture from the reactor and optionally crushing or milling, in a suitable vessel, e.g. a Soxhlet vessel.
• a suitable vessel e.g. a Soxhlet vessel.
• the liquid phase containing LiP0 2 F 2 dissolved in the solvent can be separated from the non-dissolved constituents of the reaction mixture in a known manner.
• the solution can be passed through a filter, or it can be decanted, or the separation can be effected by centrifugation.
• the solution of LiP0 2 F 2 in water-free solvents is useful as such, e.g. as an additive for the manufacture of electrolyte solutions for lithium ion batteries.
• the solution of LiP0 2 F 2 can be subjected to a separation treatment to separate the solvent and to obtain pure solid LiP0 2 F 2 .
• a separation treatment to separate the solvent and to obtain pure solid LiP0 2 F 2 .
• This can be performed in a known manner.
• the solution can be cooled to lower the solubility of the dissolved LiP0 2 F 2 , or the solvent can be removed by evaporation which may preferably be performed in a vacuum depending on the boiling point of the solvent or solvents.
• the isolated LiP0 2 F 2 can be used as additive for the manufacture of lithium ion batteries. It can also be used as additive for Li-sulfur batteries and for Li-oxygen batteries.
• Isolated solid LiP0 2 F 2 can be re-dissolved in any suitable solvent or solvent mixture, especially in at least one polar aprotic organic solvent to provide an electrolyte solution suitable for lithium ion batteries, lithium- sulfur batteries and lithium-oxygen batteries.
• a solution of LiP0 2 F 2 in propylene carbonate for example contains, under standard conditions (25°C, 1 Bara), up to about 3 % by weight of LiP0 2 F 2 relative to the total weight of the solution.
• the amount of LiP0 2 F 2 which dissolves at a given temperature will vary but can easily be determined by simple tests.
• An electrolyte solution for lithium ion batteries, lithium- sulfur batteries or lithium-oxygen batteries comprising LiP0 2 F 2 will often contain another electrolyte salt.
• LiPF 6 , LiAsF 6 , LiC10 4 , L1CF 3 SO 3 , Li (S0 2 CF 3 ) 2 , LiN(S0 2 C 2 F 5 ) 2 , Li (S0 2 -i-C 3 F 7 ) 2 , Li (S0 2 -n-C 3 F 7 ) 2 , LiBC 4 0 8 ("LiBOB"), or Li(C 2 Fs)PF 3 can additionally be contained in the electrolyte solution.
• LiPF 6 is additionally contained.
• the electrolyte solution for lithium ion batteries, for lithium- sulfur batteries or for lithium-oxygen batteries comprises one or more solvents.
• Solvents for this purpose generally aprotic polar organic solvents, are known.
• Organic carbonates, especially dialkyl carbonates, e.g. dimethyl carbonate or ethyl carbonate, alkylene carbonate, e.g. ethylene carbonate, fluorinated solvents, e.g. mono-, di-, tri- and/or tetrafluoroethylene carbonate, are very suitable.
• the electrolyte solution may comprise any other desired solvents or additives, for example, lactones, formamides, pyrrolidinones, oxazolidinones, nitroalkanes, ⁇ , ⁇ -substituted urethanes, sulfolane, dialkyl sulfoxides, dialkyl sulfites, as described in the publication of M. Ue et al. in
• Alkyl carbonates with linear and branched alkyl groups and alkylene carbonates are especially suitable, for example, ethylene carbonate, dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, and propylene carbonate, see EP-A-0 643 433. Pyro carbonates are also useful, see US-A 5,427,874.
• alkyl preferably denotes saturated linear or branched CI to C4 alkyl groups
• alkylene denotes preferably C2 to C7 alkylene groups, including a vinylidene group, wherein the alkylene group preferably comprises a bridge of 2 carbon atoms between the oxygen atoms of the -0-C(0)-0- group, thus forming a 5-membered ring.
• Fluorosubstituted compounds especially fluoro substituted carbonates, lower the flame point and have a positive effect on the life cycle of the battery.
• fluorosubstituted organic compounds are applied in the form of solvent mixtures with at least one further solvent which is preferably non-fluorinated.
• the at least one further non-fluorinated solvent is preferably selected from those solvents mentioned above.
• the non-fluorinated organic carbonates mentioned above are very suitable.
• fluorinated carbonic esters which are selected from the group of fluoro substituted ethylene carbonates
• fluoro substituted dimethyl carbonates fluoro substituted ethyl methyl carbonates, and fluoro substituted diethyl carbonates are contained.
• Preferred fluoro substituted carbonates are mono fluoro ethylene carbonate
• dimethyl carbonate derivatives including fluoromethyl methyl carbonate, difluoromethyl methyl carbonate, trifluoromethyl methyl carbonate, bis(fluoromethyl) carbonate,
• ethyl methyl carbonate derivatives including 2-fluoroethyl methyl carbonate, ethyl fluoromethyl carbonate, 2,2-difluoroethyl methyl carbonate, 2-fluoroethyl fluoromethyl carbonate, ethyl difluoromethyl carbonate, 2,2,2-trifluoroethyl methyl carbonate, 2,2-difluoroethyl fluoromethyl carbonate, 2-fluoroethyl difluoromethyl carbonate, and ethyl trifluoromethyl carbonate ; and diethyl carbonate derivatives including ethyl (2-fluoroethyl) carbonate, ethyl
• L1PO 2 F 2 is preferably dissolved in at least one solvent selected from the group consisting of dimethoxyethane, acetonitrile, non- fluoro substituted or fluoro substituted organic carbonate selected from the group consisting of ethylene carbonate, dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, propylene carbonate, mono fluoro ethylene carbonate, 4,4-difluoro ethylene carbonate, 4,5-difluoro ethylene carbonate, 4-fluoro-4-methyl ethylene carbonate, 4,5-difluoro-4-methyl ethylene carbonate, 4-fluoro-5-methyl ethylene carbonate, 4,4-difluoro-5-methyl ethylene carbonate, 4-(fluoromethyl)-ethylene carbonate, 4-(difluoromethyl)-ethylene carbonate, 4-(trifluoromethyl)-ethylene carbonate, 4-(fluoromethyl)-4-fluoro ethylene carbonate, 4-(fluoromethyl)-5- fluoro
• Ethylene carbonate dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, propylene carbonate, mono fluoro ethylene carbonate,
• 4,5-difluoroethylene carbonate and mixtures of two or more thereof, are especially preferred to dissolve LiP0 2 F 2 .
• Carbonic esters having both an unsaturated bond and a fluorine atom having both an unsaturated bond and a fluorine atom
• fluorinated unsaturated carbonic ester can also be used as the carbonic ester.
• the fluorinated unsaturated carbonic esters include any fluorinated unsaturated carbonic esters that do not significantly impair the advantages of the present invention.
• fluorinated unsaturated carbonic esters examples include vinylene carbonate derivatives, ethylene carbonate derivatives substituted by a substituent having an aromatic ring or a carbon-carbon unsaturated bond, and allyl carbonates.
• vinylene carbonate derivatives examples include f uorovinylene carbonate, 4-fluoro-5-methylvinylene carbonate and 4-fluoro-5-phenylvinylene carbonate.
• Examples of the ethylene carbonate derivatives substituted by a substituent having an aromatic ring or a carbon-carbon unsaturated bond include 4-fluoro-4- vinylethylene carbonate, 4-fluoro-5-vinylethylene carbonate, 4,4-difluoro-4- vinylethylene carbonate, 4,5-difluoro-4-vinylethylene carbonate, 4-fluoro-4,5- divinylethylene carbonate, 4,5-difluoro-4,5-divinylethylene carbonate, 4-fluoro-
• phenyl carbonates include fluoromethyl phenyl carbonate, 2-fluoroethyl phenyl carbonate, 2,2-difluoroethyl phenyl carbonate and
• vinyl carbonates examples include fluoromethyl vinyl carbonate, 2-fluoroethyl vinyl carbonate, 2,2-difluoroethyl vinyl carbonate and
• allyl carbonates examples include fluoromethyl allyl carbonate, 2-fluoroethyl allyl carbonate, 2,2-difluoroethyl allyl carbonate and
• Preferred electrolyte solutions comprise L1PO 2 F 2 in an amount of 2 to 3 % by weight and another lithium salt, preferably selected from the list of lithium salts mentioned above, such that the total concentration of the lithium slats in the electrolyte solution is about 0.9 to 1.1 molar (i.e., a total concentration
• the electrolyte solution contains at least one of the fluoro substituted carbonates mentioned above ; monofluoroethylene carbonate is the preferred compound. It is preferably contained in an amount between 0.1 to 20 % by weight of the total electrolyte solution. The balance to 100 % by weight are preferably one or more optionally non-fluorinated solvents, especially ethylene carbonate, propylene carbonate, dimethyl carbonate, methyl ethyl carbonate, or diethyl carbonate.
• an electrolyte solution comprising L1PO 2 F 2 dissolved in a mixture comprising or consisting of at least one non-fluorinated organic carbonate and at least one fluorinated organic carbonate
• Electrolyte solutions comprising LiPF 6 , L1PO 2 F 2 , at least one
• fluoro substituted carbonate selected from the group consisting of
• monofluoroethylene carbonate 4,4-difluoroethylene carbonate, cis- and/or trans-4,5-difluoroethylene carbonate, and at least one non-fluorinated carbonate selected from the group consisting of dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, ethylene carbonate and propylene carbonate are especially preferred.
• These electrolyte solutions are suitable for lithium ion batteries, for lithium- sulfur batteries and for lithium-oxygen batteries.
• Dimethoxyethane and acetonitrile are also suitable solvents or component of a solvent to provide electrolyte solutions.
• Such electrolyte solutions can be prepared by mixing the constituents in a vessel.
• the advantage of the process of the invention is among others that pure crystalline L1PO 2 F 2 can be obtained from cheap starting material, for example, when extracted from the reaction mixture with dimethyl carbonate or propylene carbonate as solvent and subsequent removal of the solvent, e.g. in a vacuum. Other solvents may yield an amorphous product.
• crystalline L1PO 2 F 2 is another aspect of the present invention. It is free of LiPF 6 . It can be produced by the process of the invention or by other methods. It shows strong 2-Theta lines at 27.0 and 21.5. In the 19 F NMR spectrum and the 31 P NMR spectrum in D6 acetone solution, a doublet and a triplet are observed, respectively, at a chemical shift typical for PO 2 F 2 anions.
• the crystalline L1PO 2 F 2 is preferably free of LiF and preferably free of LiPF 6 .
• the content of chloride anions is equal to or lower than 1000 ppm, more preferably, equal to or lower than 100 ppm and even equal to or lower than 15 ppm.
• the term "preferably free of LiF" preferably denotes a content of LiF equal to or lower than 0.1 g per lOOg of the L1PO 2 F 2 .
• preferably free of LiPF 6 preferably denotes a content of equal to or lower than 1 g, preferably equal to or lower than 0.1 g, more preferably, especially preferably equal to or 1 lower than O.Olg of LiPF 6 per lOOg of L1PO 2 F 2 .
• Example 1 was repeated by applying P4O10 and LiF in a molar ratio of 1 :6.
• the starting materials were mixed in a dry box, then mechanically mixed in a Turbula ® mixer with three dimensional flow for a few minutes, then transferred into the steel reactor, the lid was closed, and the reactor was heated for three hours in an oven at 300°C.
• the resulting solid was crushed, milled and then extracted in the Soxhlet apparatus for 24 hours. Thereafter, the solvent was removed in a Rotavapor ® at 60°C and around 100 mBar.
• Example 2 was repeated, but the extraction time was extended to 48 hours.
• Melting point a melting point cannot be determined because the compound decomposes at temperatures above about 350°C.
• Example 4 Electrolyte solution for lithium ion batteries, lithium- sulfur batteries and lithium-oxygen batteries
• Example 1 is repeated, but dimethoxyethane is applied as a solvent. Due to the extremely high solubility of L1PO 2 F 2 and the very low solubility of LiF, the extraction can be performed very fast with a relatively low amount of dimethoxyethane. The solution of L1PO 2 F 2 in dimethoxyethane is subjected to a vacuum treatment to remove the solvent under very smooth conditions.
• Example 6 Synthesis and isolation of L1PO 2 F 2 using acetonitrile as extractant Example 1 is repeated, but acetonitrile is applied as a solvent. Due to the e high solubility of L1PO 2 F 2 and the very low solubility of LiF in acetonitrile, the extraction can be performed very fast with a relatively low amount of acetonitrile.
• the solution of L1PO 2 F 2 in acetonitrile is subjected to a vacuum treatment to remove the solvent under very smooth conditions ; alternatively, due to the high purity of gthe L1PO 2 F 2 dissolved in acetonitrile, the solution could directly be applied to produce a battery electrolyte solvent.
• Example 1 is repeated, but acetone is applied as a solvent. Due to the very high solubility of L1PO 2 F 2 and the very low solubility of LiF, the extraction can be performed very fast with a relatively low amount of acetone. The solution of L1PO 2 F 2 in acetone is subjected to a vacuum treatment to remove the solvent under very smooth conditions. The low boiling point of acetone allows for a very fast but nevertheless smooth isolation of the L1PO 2 F 2 .

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• 2011
  • 2011-06-30 US US13/808,242 patent/US20130108933A1/en not_active Abandoned
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