WO2015028346A1 - Production of metal difluorophosphates in an inorganic solvent - Google Patents
Production of metal difluorophosphates in an inorganic solvent Download PDFInfo
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- WO2015028346A1 WO2015028346A1 PCT/EP2014/067622 EP2014067622W WO2015028346A1 WO 2015028346 A1 WO2015028346 A1 WO 2015028346A1 EP 2014067622 W EP2014067622 W EP 2014067622W WO 2015028346 A1 WO2015028346 A1 WO 2015028346A1
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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
- H01M10/056—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
- H01M10/0567—Liquid materials characterised by the additives
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- 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
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D15/00—Lithium compounds
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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
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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
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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
- H01M12/00—Hybrid cells; Manufacture thereof
- H01M12/04—Hybrid cells; Manufacture thereof composed of a half-cell of the fuel-cell type and of a half-cell of the primary-cell type
- H01M12/06—Hybrid cells; Manufacture thereof composed of a half-cell of the fuel-cell type and of a half-cell of the primary-cell type with one metallic and one gaseous electrode
-
- 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 production of metal difluorophosphates, specifically to the production of L1PO 2 F 2 , in an inorganic solvent. More specifically, it relates to a method for the production of metal difluorophosphates comprising a step of reacting a phosphorus-containing reactant selected from the group consisting of phosphorus pentafluoride (PF 5 ), phosphoryl fluoride (POF 3 ), and mixtures thereof, with a metal orthophosphate, bicarbonate or carbonate in an inorganic solvent, preferably in an excess of the phosphorus-containing reactant.
- PF 5 phosphorus pentafluoride
- POF 3 phosphoryl fluoride
- Metal difluorophosphates are useful compounds in electrolyte
- compositions for metal ion batteries As a specific example, lithium
- difluorophosphate L1PO 2 F 2
- L1PO 2 F 2 is useful as electrolyte salt or additive for an electrolyte composition used in lithium ion batteries.
- WO 2012/016924 describes the reaction of solid L1 3 PO 4 with gaseous POF 3 and/or PF 5 to yield LiP0 2 F 2 . Furthermore, WO 2012/016924 outlines the possibility of performing the process in presence of an aprotic organic solvent.
- the invention makes available an improved process for the production of metal difluorophosphates, specifically for the production of L1PO 2 F 2 in a technically feasible and economical manner. It is an object of the present invention to provide a process for the production of metal difluorophosphates, specifically for the production of L1PO 2 F 2 , which is advantageous in terms of the overall yield, the purity, the physicochemical properties including but not limited to the crystallinity and/or density of the product, the energy consumption, the safety requirements, the ease of work-up, and/or the side-product profile. Furthermore, it is an object of the present invention to provide L1PO 2 F 2 in a form which is advantageous in terms of stability, solubility, crystallinity, dissolution rate, and/or ease of handling.
- Figure 1 shows the XRD pattern of L1PO2F2 produced according to the procedure of example 1.
- one embodiment of the present invention is a process for the production of a compound of general formula MPO 2 F 2 , wherein M is Li, Na or K; comprising a reaction step (I) of a compound of the general
- the inventive process is not limited to the metals M as given above. It can also be used to produce metal difluorophosphates of other metals like Mg, Zn, Ca, Sr, Ba, or Fe.
- M is Li.
- the reaction is the reaction of L1 3 PO 4 with POF 3 to form L1PO 2 F 2 . Accordingly,
- L1PO 2 F 2 is produced by the reaction of phosphoryl fluoride (POF 3 ) and lithium orthophosphate (L1 3 PO 4 ) following the reaction scheme:
- solvent is intended to denote a chemical compound which is a liquid under the reaction conditions of reaction step (I) and in which at least part of the starting materials, reactants and/or reaction products is dissolved during the performance of reaction step (I).
- inorganic is intended to denote any compound that lacks both carbon and hydrogen atoms.
- inorganic solvents include carbon monoxide, carbon dioxide, hydrogen fluoride, urea, POF 3 , PF 5 and mixtures thereof. Although some of the aforementioned inorganic solvents are solid or gaseous under ambient conditions, they fall under the definition "inorganic solvent” as used in the context of this invention when in the liquid state under the reaction conditions of reaction step (I). In one preferred embodiment, supercritical CO 2 is used as the inorganic solvent. In another preferred embodiment the
- the phosphorous-containing reactant according to this invention is used as the inorganic solvent, more preferably POF 3 is used as the inorganic solvent.
- POF 3 is used as the inorganic solvent.
- the initial molar ratio of POF 3 to L1 3 PO 4 is equal to or greater than 1 and equal to or lower than 3.
- the phosphorous-containing reactant is used in an excess molar ratio.
- the preferred molar ratio of POF 3 to L1 3 PO 4 is equal to or greater than 2, more preferably equal to or greater than 5.
- the ratio is suitably chosen to create a liquid phase of POF 3 under the given reactor volume at room temperature.
- Phosphoryl fluoride can be obtained commercially, e.g. from ABCR GmbH & Co. KG, or can be prepared by a known process in the art.
- POF 3 can be prepared by fluorination of phosphoryl chloride with HF and/or other fluorinating agents, for example, ZnF 2 .
- it may be also prepared by the reaction of H3PO4/P2O5, HF/H 2 0 and SO3/H2SO4.
- the POF 3 obtained may contain PF 5 as impurity, or vice versa, PF 5 may comprise POF 3 as impurity.
- the advantage of the process of the invention is that even such mixtures can be applied without impact on the yield.
- PF 5 may be obtained commercially, e.g. from Praxair, or it may be prepared from PCI 5 and HF or, as described in EP-A-0816287, for example
- L1 3 PO 4 is commercially available, e.g. from Strem Chemicals, Inc, Newburyport, USA, or from Chemetall GmbH, Germany. It is a solid with a melting point far above 1000°C.
- the reaction between PF 5 and L1 3 PO 4 , between POF 3 and L1 3 PO 4 and between mixtures of POF 3 and PF 5 , respectively, and L1 3 PO 4 is performed in the absence of water or moisture. 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 and/or
- Fluorpolymer (Teflon ® ) coated.
- L1 3 PO 4 is preferably applied in the form of small particles, e.g. in the form of a powder. If desired, it can be dried before introducing it into the reaction.
- the reaction conditions are chosen in a way that at least part of the inorganic solvent is in the liquid state.
- the reaction is performed under a pressure of equal to or higher than 6 bar, preferably equal to or higher than 8 bar, more preferably equal to of higher than 10 bar.
- the reaction is performed at a pressure of equal to or below 20 bar, more preferably equal to or below 15 bar.
- the reaction is performed at a reaction temperature from 0 to 95 °C, preferably from 15 to 80°C, more preferably from 20 to 65 °C.
- the reaction time is selected such that the desired degree of conversion is achieved. Often, a reaction time of 1 second to 5 hours gives good results for the reaction between POF 3 , PF 5 and any mixtures thereof with L1 3 PO 4 . For the reaction between POF 3 and L1 3 PO 4 , a preferred reaction time of 0.5 to 5 hours gives good results. For the reaction between PF 5 or mixtures of PF 5 and POF 3 and L1 3 PO 4 , a preferred reaction time of 0.5 to 2 hours, most preferably of around 1 hour gives good results, too. The reaction speed is generally very fast.
- the inorganic solvent can be removed after reaction step (I) by venting the reaction vessel.
- the crude product thus obtained may optionally be treated further to remove residual reactant, inorganic solvent or by-products.
- the crude product may optionally be purged with a stream of nitrogen, subjected to elevated temperatures and/or subjected to reduced pressure.
- the inorganic solvent can be recycled after the reaction step (I). If POF 3 is used as the inorganic solvent it can be removed from the reaction vessel in gaseous form by lowering the pressure in the reaction vessel, collected in a further suitable vessel and re-used for a subsequent reaction step.
- the inorganic solvent can optionally be purified before being re-used.
- embodiment is a process comprising a further reaction step (II) wherein the crude reaction product from reaction step (I) is dissolved in a solvent mixture comprising a protic solvent, preferably comprising an alcohol, more preferably comprising methanol. Subsequently, the product may be isolated by means of spray drying, evaporation of the solvent, crystallisation, lyophilization or a mixture thereof, preferably by means of crystallisation. If a crystallisation step is performed, this step can be performed using cold crystallisation, anti-solvent crystallisation, seeding or a mixture of these technologies.
- protic solvent is intended to denote a solvent that has a hydrogen atom bound to an oxygen atom (as in a hydroxyl group) or a nitrogen atom (as in an amine group).
- the mixture obtained after the reaction step (I) and/or (II) can be too acidic possibly leading to a product of lower quality after isolation.
- the mixture obtained after the reaction step (I) and/or (II) is subjected to a neutralization step.
- the neutralization step is performed in the presence of L1 2 CO 3 .
- the neutralization agent preferably a carbonate or bicarbonate, more preferably lithium carbonate
- the neutralization agent is added to the mixture after the reaction step (I) and/or (II), preferably added in solid form to a solution or slurry of the crude product from reaction step (I) in a suitable solvent, preferably in methanol.
- the pH of the mixture after the neutralization step is from 4 to 7, preferably from 5.5 to 6.5, more preferably about 6.
- Another embodiment of the present invention concerns a process for the production of a compound of the general formula MPO 2 F 2 , wherein M is Li, Na or K, comprising a reaction step (I) of a compound of general formula M 3 PO 4 , M 3 PO 4 , M 2 CO 3 , and MHCO 3 , or a mixture thereof, wherein each M is defined as above, with POF 3 , PF 5 or a mixture thereof, to form the compound of general formula MPO 2 F 2 , wherein the reaction is performed in the presence of an organic solvent, preferably in an organic solvent in which the compound of general formula MPO 2 F 2 has a solubility of > 1 g/1 at ambient conditions, preferably of > 5 g/1, more preferably of > 10 g/1.
- the process is not limited to the metals M as given above. It can also be used to produce metal difluorophosphates of other metals like Mg, Zn, Ca, Sr, Ba, or Fe.
- M is Li.
- the reaction is the reaction of L1 3 PO 4 with POF 3 to form L1PO 2 F 2 .
- organic solvent is intended to denote any compound comprising at least one carbon atom that is liquid under the reaction conditions.
- the organic solvent does not react with any of the starting materials or the reaction product.
- organic solvent are aprotic organic solvents, for example cyclic and acyclic ethers, esters, ketones, carbonates, nitriles, sulfones and mixtures thereof wherein the solubility of the compound of general formula MPO 2 F 2 is > 1 g/1 at ambient conditions.
- Examples of useful organic solvents include acetone, acetonitrile,
- ambient conditions is intended to denote conditions referring to the standard ambient temperature and pressure (25°C, 100 kPa).
- solubility is intended to denote the analytical composition of a saturated solution expressed as a proportion of a designated solute in a designated solvent according to IUPAC definition.
- the organic solvent is a diether or a poly ether, more preferably a diether, most preferably the diether is 1,2 dimethoxy ethane.
- diether is intended to denote a compound comprising two moieties of the structural motif "C-O-C", i.e. a compound comprising two oxygen atoms each directly connected to two groups selected from alkyl, alkylene, (hetero)aryl or (hetero)arylene.
- polyether is intended to denote a compound comprising at least three moieties of the structural motif "C-O-C",
- the diether and/or polyether can advantageously be substituted, for example substituted by fluorine.
- the diether and/or polyether can advantageously be cyclic or acyclic.
- Useful examples of diethers are 1,2-diethoxyethane.
- Useful examples of polyethers are glymes of the general
- the organic solvent is 1,2-dimethoxyethane.
- inventive process yields LiP0 2 F 2 with superior characteristics, especially in terms of crystallinity and/or purity.
- another aspect of the present invention concerns LiP0 2 F 2 obtainable using the inventive process as described above.
- Yet another aspect of the present invention concerns crystalline LiP0 2 F 2 characterized by an X-ray powder diffraction pattern showing the two strongest peaks at 22.6 ⁇ 0.2 and 27.3 ⁇ 0.2 0 2-Theta, preferably characterized by an X-ray powder diffraction pattern showing the four strongest peaks at 19.9 ⁇ 0.2, 20.6 ⁇ 0.2, 22.6 ⁇ 0.2, 27.3 ⁇ 0.2 0 2-Theta.
- Still another aspect of the present invention concerns crystalline LiP0 2 F 2 characterized by an X-ray powder diffraction pattern essentially as shown in Figure 1.
- a further aspect concerns crystalline LiP0 2 F 2 characterized by a bulk density of ⁇ 500 g/1, preferably between 100 and 400 g/1, more preferably between 200 and 300 g/1.
- Yet another aspect of the present invention concerns an electrolyte composition for lithium-ion batteries, lithium- sulfur batteries and/or lithium- oxygen batteries comprising the crystalline L1PO 2 F 2 according to this invention and further comprising a solvent suitable for electrolyte solutions for lithium-ion batteries, lithium- sulfur batteries and/or lithium-oxygen batteries.
- Solvents suitable for electrolyte solutions for lithium- ion batteries, lithium- sulfur batteries and/or lithium-oxygen batteries are known in the art. Suitable examples include 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, 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 and fluorinated derivatives of the compounds mentioned in this paragraph, e.g. l-fluoroethyl methyl carbonate, 4-fluoroethylene carbonate or l-fluoroethyl allyl carbonate.
- the concentration of the metal difluorophosphates of the invention in the electrolyte solution is preferably 1 ⁇ 0.2 molar.
- the electrolyte solution may comprise LiPF 6 and L1PO2F2.
- the combined concentration of the two compounds in the electrolyte solution is preferably 1 ⁇ 0.2 molar.
- the reactor is charged with L1 3 PO 4 (5.8 kg, 50 mol) and cooled to 16°C.
- POF 3 (35.5 kg, 350 mol) is fed to a pressure of 14 bar(g) in the reactor while agitating the L1 3 PO 4 . During addition of the POF 3 the temperature rises continuously to 60°C. After 16 h, the excess POF 3 is pumped off and can be recycled for the next batch. The reactor (double jacket) is then heated to 140°C to evaporate residual gas while under vacuum with an additional purge of 300 1/h nitrogen for 24 h. Subsequently, the reactor is cooled to room temperature and 38 kg MeOH is added. The solution is being processed by filtration through a 5 ⁇ Teflon ® sieve.
- the filtrate can be further treated by either
- Table 1 XRD data for the compound according to example 1(B)
- the crude product is dried at 100°C and 100 mbar using a flow of nitrogen of 100 1/h for 18 h to yield 146 g (90 %) of the product.
- Example 3 Electrolyte solution for lithium ion batteries, lithium sulfur batteries and/or lithium-oxygen batteries
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Abstract
The present invention relates to a method for the production of metal difluorophosphates, specifically to the production of LiPO2F2, in an inorganic solvent. More specifically, it relates to a method for the production of metal difluorophosphates comprising a step of reacting a phosphorus-containing reactant selected from the group consisting of phosphorus pentafluoride (PF5),phosphoryl fluoride (POF3), and mixtures thereof, with a metal orthophosphate, bicarbonate or carbonate in an inorganic solvent, preferably in an excess of the phosphorus-containing reactant.
Description
Production of metal difluorophosphates in an inorganic solvent
This application claims priority to European applications No. 13182079.7, filed August 28, 2013 and No. 14153455.2, filed January 31 , 2014, the whole content of these applications being incorporated herein by reference for all purposes.
The present invention relates to a method for the production of metal difluorophosphates, specifically to the production of L1PO2F2, in an inorganic solvent. More specifically, it relates to a method for the production of metal difluorophosphates comprising a step of reacting a phosphorus-containing reactant selected from the group consisting of phosphorus pentafluoride (PF5), phosphoryl fluoride (POF3), and mixtures thereof, with a metal orthophosphate, bicarbonate or carbonate in an inorganic solvent, preferably in an excess of the phosphorus-containing reactant.
Metal difluorophosphates are useful compounds in electrolyte
compositions for metal ion batteries. As a specific example, lithium
difluorophosphate, L1PO2F2, is useful as electrolyte salt or additive for an electrolyte composition used in lithium ion batteries.
WO 2012/016924 describes the reaction of solid L13PO4 with gaseous POF3 and/or PF5 to yield LiP02F2. Furthermore, WO 2012/016924 outlines the possibility of performing the process in presence of an aprotic organic solvent.
Now therefore, the invention makes available an improved process for the production of metal difluorophosphates, specifically for the production of L1PO2F2 in a technically feasible and economical manner. It is an object of the present invention to provide a process for the production of metal difluorophosphates, specifically for the production of L1PO2F2, which is advantageous in terms of the overall yield, the purity, the physicochemical properties including but not limited to the crystallinity and/or density of the product, the energy consumption, the safety requirements, the ease of work-up, and/or the side-product profile. Furthermore, it is an object of the present invention to provide L1PO2F2 in a form which is advantageous in terms of stability, solubility, crystallinity, dissolution rate, and/or ease of handling.
This object and other objects are achieved by the invention as outlined in the patent claims.
Brief description of the drawing
Figure 1 shows the XRD pattern of L1PO2F2 produced according to the procedure of example 1.
Accordingly, one embodiment of the present invention is a process for the production of a compound of general formula MPO2F2, wherein M is Li, Na or K; comprising a reaction step (I) of a compound of the general
formula M3PO4, M2CO3, MHCO3 or a mixture thereof, wherein each M is defined as above; with a phosphorous-containing reactant selected from the group consisting of POF3, PF5 and a mixture thereof; to form the compound of general formula MPO2F2, wherein the reaction is performed in the presence of an inorganic solvent. The inventive process is not limited to the metals M as given above. It can also be used to produce metal difluorophosphates of other metals like Mg, Zn, Ca, Sr, Ba, or Fe.
In a preferred embodiment, M is Li. In a more preferred embodiment, the reaction is the reaction of L13PO4 with POF3 to form L1PO2F2. Accordingly,
L1PO2F2 is produced by the reaction of phosphoryl fluoride (POF3) and lithium orthophosphate (L13PO4) following the reaction scheme:
2POF3 + L13PO4 -> 3 L1PO2F2
The term "solvent" is intended to denote a chemical compound which is a liquid under the reaction conditions of reaction step (I) and in which at least part of the starting materials, reactants and/or reaction products is dissolved during the performance of reaction step (I).
The term "inorganic" is intended to denote any compound that lacks both carbon and hydrogen atoms.
Suitable examples of inorganic solvents include carbon monoxide, carbon dioxide, hydrogen fluoride, urea, POF3, PF5 and mixtures thereof. Although some of the aforementioned inorganic solvents are solid or gaseous under ambient conditions, they fall under the definition "inorganic solvent" as used in the context of this invention when in the liquid state under the reaction conditions of reaction step (I). In one preferred embodiment, supercritical CO2 is used as the inorganic solvent. In another preferred embodiment the
phosphorous-containing reactant according to this invention is used as the inorganic solvent, more preferably POF3 is used as the inorganic solvent. Thus, one compound can serve both the roles of the phosphorous-containing reactant as well as the inorganic solvent.
Preferably, the initial molar ratio of POF3 to L13PO4 is equal to or greater than 1 and equal to or lower than 3. Also preferably, the phosphorous-containing reactant is used in an excess molar ratio. In case of the reaction of L13PO4 with POF3, the preferred molar ratio of POF3 to L13PO4 is equal to or greater than 2, more preferably equal to or greater than 5. Alternatively, the ratio is suitably chosen to create a liquid phase of POF3 under the given reactor volume at room temperature.
Phosphoryl fluoride (POF3) can be obtained commercially, e.g. from ABCR GmbH & Co. KG, or can be prepared by a known process in the art. For example, POF3 can be prepared by fluorination of phosphoryl chloride with HF and/or other fluorinating agents, for example, ZnF2. Alternatively, it may be also prepared by the reaction of H3PO4/P2O5, HF/H20 and SO3/H2SO4. Sometimes, the POF3 obtained may contain PF5 as impurity, or vice versa, PF5 may comprise POF3 as impurity. The advantage of the process of the invention is that even such mixtures can be applied without impact on the yield.
PF5 may be obtained commercially, e.g. from Praxair, or it may be prepared from PCI5 and HF or, as described in EP-A-0816287, for example
L13PO4 is commercially available, e.g. from Strem Chemicals, Inc, Newburyport, USA, or from Chemetall GmbH, Germany. It is a solid with a melting point far above 1000°C.
Preferably, the reaction between PF5 and L13PO4, between POF3 and L13PO4 and between mixtures of POF3 and PF5, respectively, and L13PO4 is performed in the absence of water or moisture. 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 and/or
Fluorpolymer (Teflon®) coated.
L13PO4 is preferably applied in the form of small particles, e.g. in the form of a powder. If desired, it can be dried before introducing it into the reaction.
The reaction conditions are chosen in a way that at least part of the inorganic solvent is in the liquid state. To this end it is preferred that the reaction is performed under a pressure of equal to or higher than 6 bar, preferably equal to or higher than 8 bar, more preferably equal to of higher than 10 bar. Also preferably, the reaction is performed at a pressure of equal to or below 20 bar, more preferably equal to or below 15 bar. Also preferably, the reaction is
performed at a reaction temperature from 0 to 95 °C, preferably from 15 to 80°C, more preferably from 20 to 65 °C.
The reaction time is selected such that the desired degree of conversion is achieved. Often, a reaction time of 1 second to 5 hours gives good results for the reaction between POF3, PF5 and any mixtures thereof with L13PO4. For the reaction between POF3 and L13PO4, a preferred reaction time of 0.5 to 5 hours gives good results. For the reaction between PF5 or mixtures of PF5 and POF3 and L13PO4, a preferred reaction time of 0.5 to 2 hours, most preferably of around 1 hour gives good results, too. The reaction speed is generally very fast.
In case the inorganic solvent is gaseous under ambient conditions, the inorganic solvent can be removed after reaction step (I) by venting the reaction vessel. The crude product thus obtained may optionally be treated further to remove residual reactant, inorganic solvent or by-products. To this end, the crude product may optionally be purged with a stream of nitrogen, subjected to elevated temperatures and/or subjected to reduced pressure.
In a preferred embodiment, the inorganic solvent can be recycled after the reaction step (I). If POF3 is used as the inorganic solvent it can be removed from the reaction vessel in gaseous form by lowering the pressure in the reaction vessel, collected in a further suitable vessel and re-used for a subsequent reaction step. The inorganic solvent can optionally be purified before being re-used.
Purification and/or crystallization of L1PO2F2 in aprotic organic solvents have been described in the prior art. Surprisingly, it has now been found that a compound of general formula MPO2F2, preferably L1PO2F2, can be purified by recrystallisation of the compound from a pro tic organic solvent, preferably from an alcohol, more preferably from methanol. Thus, another preferred
embodiment is a process comprising a further reaction step (II) wherein the crude reaction product from reaction step (I) is dissolved in a solvent mixture comprising a protic solvent, preferably comprising an alcohol, more preferably comprising methanol. Subsequently, the product may be isolated by means of spray drying, evaporation of the solvent, crystallisation, lyophilization or a mixture thereof, preferably by means of crystallisation. If a crystallisation step is performed, this step can be performed using cold crystallisation, anti-solvent crystallisation, seeding or a mixture of these technologies.
The term "protic solvent" is intended to denote a solvent that has a hydrogen atom bound to an oxygen atom (as in a hydroxyl group) or a nitrogen atom (as in an amine group).
The mixture obtained after the reaction step (I) and/or (II) can be too acidic possibly leading to a product of lower quality after isolation. Thus, in another preferred embodiment the mixture obtained after the reaction step (I) and/or (II) is subjected to a neutralization step. Preferably, the neutralization step is performed in the presence of L12CO3. To this end, the neutralization agent, preferably a carbonate or bicarbonate, more preferably lithium carbonate, is added to the mixture after the reaction step (I) and/or (II), preferably added in solid form to a solution or slurry of the crude product from reaction step (I) in a suitable solvent, preferably in methanol. Advantageously, the pH of the mixture after the neutralization step is from 4 to 7, preferably from 5.5 to 6.5, more preferably about 6.
Another embodiment of the present invention concerns a process for the production of a compound of the general formula MPO2F2, wherein M is Li, Na or K, comprising a reaction step (I) of a compound of general formula M3PO4, M3PO4, M2CO3, and MHCO3, or a mixture thereof, wherein each M is defined as above, with POF3, PF5 or a mixture thereof, to form the compound of general formula MPO2F2, wherein the reaction is performed in the presence of an organic solvent, preferably in an organic solvent in which the compound of general formula MPO2F2 has a solubility of > 1 g/1 at ambient conditions, preferably of > 5 g/1, more preferably of > 10 g/1. The process is not limited to the metals M as given above. It can also be used to produce metal difluorophosphates of other metals like Mg, Zn, Ca, Sr, Ba, or Fe.
In a preferred embodiment, M is Li. In a more preferred embodiment, the reaction is the reaction of L13PO4 with POF3 to form L1PO2F2.
The term "organic solvent" is intended to denote any compound comprising at least one carbon atom that is liquid under the reaction conditions. Advantageously, the organic solvent does not react with any of the starting materials or the reaction product. Useful examples of an organic solvent are aprotic organic solvents, for example cyclic and acyclic ethers, esters, ketones, carbonates, nitriles, sulfones and mixtures thereof wherein the solubility of the compound of general formula MPO2F2 is > 1 g/1 at ambient conditions.
Examples of useful organic solvents include acetone, acetonitrile,
dimethylformamide, sulfolane.
The term "ambient conditions" is intended to denote conditions referring to the standard ambient temperature and pressure (25°C, 100 kPa).
The term "solubility" is intended to denote the analytical composition of a saturated solution expressed as a proportion of a designated solute in a designated solvent according to IUPAC definition.
In a preferred embodiment, the organic solvent is a diether or a poly ether, more preferably a diether, most preferably the diether is 1,2 dimethoxy ethane. The term "diether" is intended to denote a compound comprising two moieties of the structural motif "C-O-C", i.e. a compound comprising two oxygen atoms each directly connected to two groups selected from alkyl, alkylene, (hetero)aryl or (hetero)arylene. The term "polyether" is intended to denote a compound comprising at least three moieties of the structural motif "C-O-C",
i.e. a compound comprising at least three oxygen atoms each directly connected to two groups selected from alkyl, alkylene, (hetero)aryl or (hetero)arylene. The diether and/or polyether can advantageously be substituted, for example substituted by fluorine. The diether and/or polyether can advantageously be cyclic or acyclic. Useful examples of diethers are 1,2-diethoxyethane. Useful examples of polyethers are glymes of the general
formula CH30(CH2CH20)nCH3 with n > 1 or crown ethers, for
example 12-crown-4, 15-crown-5, 18-crown-6, dibenzo-18-crown-6. Most preferably, the organic solvent is 1,2-dimethoxyethane.
The inventive process yields LiP02F2 with superior characteristics, especially in terms of crystallinity and/or purity. Thus, another aspect of the present invention concerns LiP02F2 obtainable using the inventive process as described above.
Yet another aspect of the present invention concerns crystalline LiP02F2 characterized by an X-ray powder diffraction pattern showing the two strongest peaks at 22.6 ± 0.2 and 27.3 ± 0.2 0 2-Theta, preferably characterized by an X-ray powder diffraction pattern showing the four strongest peaks at 19.9 ± 0.2, 20.6 ± 0.2, 22.6 ± 0.2, 27.3 ± 0.2 0 2-Theta.
Still another aspect of the present invention concerns crystalline LiP02F2 characterized by an X-ray powder diffraction pattern essentially as shown in Figure 1.
A further aspect concerns crystalline LiP02F2 characterized by a bulk density of < 500 g/1, preferably between 100 and 400 g/1, more preferably between 200 and 300 g/1.
Yet another aspect of the present invention concerns an electrolyte composition for lithium-ion batteries, lithium- sulfur batteries and/or lithium-
oxygen batteries comprising the crystalline L1PO2F2 according to this invention and further comprising a solvent suitable for electrolyte solutions for lithium-ion batteries, lithium- sulfur batteries and/or lithium-oxygen batteries.
Solvents suitable for electrolyte solutions for lithium- ion batteries, lithium- sulfur batteries and/or lithium-oxygen batteries are known in the art. Suitable examples include 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, 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, and fluorinated derivatives of the compounds mentioned in this paragraph, e.g. l-fluoroethyl methyl carbonate, 4-fluoroethylene carbonate or l-fluoroethyl allyl carbonate.
The concentration of the metal difluorophosphates of the invention in the electrolyte solution is preferably 1 ± 0.2 molar. Often, the electrolyte solution may comprise LiPF6 and L1PO2F2. In the case, the combined concentration of the two compounds in the electrolyte solution is preferably 1 ± 0.2 molar.
Should the disclosure of any of the patents, patent applications, and publications that are incorporated herein by reference be in conflict with the present description to the extent that it might render a term unclear, the present description shall take precedence.
Examples
Example 1 : Production of LiPOiFi
The reactor is charged with L13PO4 (5.8 kg, 50 mol) and cooled to 16°C.
POF3 (35.5 kg, 350 mol) is fed to a pressure of 14 bar(g) in the reactor while agitating the L13PO4. During addition of the POF3 the temperature rises continuously to 60°C. After 16 h, the excess POF3 is pumped off and can be recycled for the next batch. The reactor (double jacket) is then heated to 140°C to evaporate residual gas while under vacuum with an additional purge of 300 1/h nitrogen for 24 h. Subsequently, the reactor is cooled to room temperature and 38 kg MeOH is added. The solution is being processed by filtration through a 5 μιη Teflon® sieve.
The filtrate can be further treated by either
(A) Being transferred to a evaporation unit to produce crude L1PO2F2 in form of crystals. The crystals can be transferred to a glove box and milled to a fine
powder, which again is vacuum dried (100 °C and 100 mbar using a flow of nitrogen of 100 1/h) to remove residual solvent from the crystallization step. The accumulated yield is 85 %.
or
(B) Being spray dried under controlled and ex-proof condition, which results also in a 85 % yield of LiP02F2.
Analytical data
PXR (powder X-ray diffraction): Samples were analysed on a Broker AXS D8 Advance powder X-ray diffractometer. The wavelength of the radiation was 1.5406Λ.
Measurement conditions were as follows.
Position [° 2 Theta] Intensity [counts] Position [° 2 Theta] Intensity [counts]
13,03 538,88 46,08 310,03
19,91 7900, 17 46,52 101 1 ,01
20,64 9222,67 46,89 509,58
21 ,37 1732,4 47,55 1897,22
21 ,78 2100,5 48,29 272,25
22,55 17484,82 50,88 588, 15
23,32 631 ,65 51 ,81 479,78
26,27 2304,76 53,45 560,08
27,31 16984,9 54,33 464,72
27,86 6620,6 55, 12 674,57
28,45 729, 1 1 56,35 306,58
29,59 439,26 57,41 269,72
30,56 1769,7 57,72 302,43
32,25 885,48 59,08 343,91
32,51 1351 ,54 59,66 203,39
33,90 2813,27 60,61 544,44
35,42 426,98 62,45 340,32
37,64 245, 17 67,40 246,56
38, 13 1005,28 68,07 288,53
38,67 394,43 69,21 269,34
39,53 381 ,03 69,72 167,86
40,46 1695,09 71 ,07 206,26
42,01 549,94 71 ,84 280, 12
43,51 344,46 73,04 151 ,94
44,94 446,99
Table 1 : XRD data for the compound according to example 1(B)
19F-NMR (470.94 MHz; D6-acetone): -84.25 ppm (doublet, J= 926 Hz) The bulk density at ambient conditions of the L1PO2F2 according to example 1 was determined to be 280 g/1. In a comparable example, the bulk density of the L1PO2F2 prepared according to example 3 of WO 2012/016924 was determined to be 560 g/1.
Example 2 : Production of LiPOiFi
58 g Li3P04 was dried at 200°C for 18 h and subsequently placed in a Teflon® reactor equipped with a paddle mixer and a Teflon® condenser.
Dimethoxy ethane (500 ml) was added and the mixture was stirred at 200 rpm. The reaction vessel was subjected to a nitrogen atmosphere and subsequently, POF3 (103.4 g) was introduced into the mixture via an immersion tube at room temperature over a period of 4.5 h. After the introduction of POF3 was completed, reaction mixture and vessel were flushed with nitrogen gas for 30 min. 25 g lithium carbonate was added and stirring continued for another 10 min. The mixture was filtered through a 10 μιη Teflon® filter with suction (300 mbar on the filtrate side). The filtrate showed pH 6. Volatiles were removed by means of a spray dryer (Buechi B-295- Inert Loop) under the following conditions: inlet temperature 202°C, outlet temperature 115°C, feed rate 7 g/min.
The crude product is dried at 100°C and 100 mbar using a flow of nitrogen of 100 1/h for 18 h to yield 146 g (90 %) of the product.
Example 3 : Electrolyte solution for lithium ion batteries, lithium sulfur batteries and/or lithium-oxygen batteries
117 g LiPF6, 23 g LiP02F2 (obtained analogously to example 1),
50 g 4-fluoroethylene carbonate and propylene carbonate are mixed in amount such that a total volume of 1 liter is obtained. The resulting solution contains 0.77 mol LiPF6 and 0.23 mol LiP02F2.
Claims
1. A process for the production of a compound of general
formula MPO2F2, wherein M is Li, Na or K; comprising a reaction step (I) of a compound of the general formula M3PO4, M2CO3, MHCO3 or a mixture thereof, wherein each M is defined as above; with a phosphorous-containing reactant selected from the group consisting of POF3, PF5 and a mixture thereof; to form the compound of general formula MPO2F2, wherein the reaction is performed in the presence of an inorganic solvent.
2. The process according to claim 1 wherein M is Li.
3. The process according to claim 1 or 2 comprising the reaction step (I) is the reaction of L13PO4 with POF3 to form L1PO2F2.
4. The process according to any one of claims 1 to 3 wherein the reaction is performed under a pressure of equal to or higher than 6 bar, preferably equal to or higher than 8 bar, more preferably equal to of higher than 10 bar.
5. The process according to any one of claims 1 to 4 wherein the reaction is performed at a reaction temperature from 0 to 100°C, preferably from 10 to 70°C.
6. The process according to any one of claims 1 to 5 wherein the phosphorous-containing reactant is used as the inorganic solvent, preferably POF3 is used as the inorganic solvent.
7. The process according to any one of claims 1 to 6 wherein the phosphorous-containing reactant is used in an excess molar ratio.
8. The process according to any one of claims 1 to 6 wherein the reaction is performed in excess POF3.
9. The process according to claim 8 wherein the excess POF3 is recycled.
10. The process according to any one of claims 1 to 9 comprising a further reaction step (II) wherein the crude reaction product from reaction step (I) is dissolved in a solvent mixture comprising an alcohol, preferably comprising methanol.
11. L1PO2F2 obtainable using the process according to any one of claims 1 to 10.
12. Crystalline L1PO2F2 characterized by an X-ray powder diffraction pattern showing the two strongest peaks at 22.6 ± 0.2 and 27.3 ± 0.2 0 2-Theta.
13. The crystalline L1PO2F2 according to claim 12 characterized by an X-ray powder diffraction pattern showing the four strongest peaks at 19.9 ± 0.2, 20.6 ± 0.2, 22.6 ± 0.2, 27.3 ± 0.2 0 2-Theta.
14. Crystalline L1PO2F2 characterized by an X-ray powder diffraction pattern essentially as shown in Figure 1.
15. An electrolyte composition for lithium- ion batteries, lithium-sulfur batteries and/or lithium-oxygen batteries comprising the crystalline L1PO2F2 according to any one of the claims 11 to 14 and further comprising a solvent suitable for electrolyte composition for lithium-ion batteries, lithium-sulfur batteries and/or lithium-oxygen batteries.
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EP13182079.7A EP2842908A1 (en) | 2013-08-28 | 2013-08-28 | Production of metal difluorophosphates in liquid phase |
EP13182079.7 | 2013-08-28 | ||
EP14153455 | 2014-01-31 | ||
EP14153455.2 | 2014-01-31 |
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Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN106882782A (en) * | 2017-03-25 | 2017-06-23 | 山东永浩新材料科技有限公司 | A kind of synthetic method of difluorophosphate |
WO2018143057A1 (en) * | 2017-01-31 | 2018-08-09 | 三井化学株式会社 | Method for producing lithium difluorophosphate |
CN109133023A (en) * | 2017-06-27 | 2019-01-04 | 天津金牛电源材料有限责任公司 | The circulation utilization method of nonaqueous solvents in a kind of difluorophosphate preparation process |
CN112758904A (en) * | 2019-11-22 | 2021-05-07 | 多氟多化工股份有限公司 | Preparation method of lithium difluorophosphate |
WO2023120068A1 (en) * | 2021-12-21 | 2023-06-29 | 冨士色素株式会社 | Electrolyte solution |
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WO2012016924A1 (en) * | 2010-08-04 | 2012-02-09 | Solvay Sa | Manufacture of lipo2f2 from pof3 or pf5 |
WO2013023902A1 (en) * | 2011-08-16 | 2013-02-21 | Solvay Sa | Manufacture of mixtures comprising lipo2f2 and lipf6 |
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2014
- 2014-08-19 WO PCT/EP2014/067622 patent/WO2015028346A1/en active Application Filing
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
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WO2012016924A1 (en) * | 2010-08-04 | 2012-02-09 | Solvay Sa | Manufacture of lipo2f2 from pof3 or pf5 |
WO2013023902A1 (en) * | 2011-08-16 | 2013-02-21 | Solvay Sa | Manufacture of mixtures comprising lipo2f2 and lipf6 |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2018143057A1 (en) * | 2017-01-31 | 2018-08-09 | 三井化学株式会社 | Method for producing lithium difluorophosphate |
JPWO2018143057A1 (en) * | 2017-01-31 | 2019-11-07 | 三井化学株式会社 | Method for producing lithium difluorophosphate |
CN106882782A (en) * | 2017-03-25 | 2017-06-23 | 山东永浩新材料科技有限公司 | A kind of synthetic method of difluorophosphate |
CN109133023A (en) * | 2017-06-27 | 2019-01-04 | 天津金牛电源材料有限责任公司 | The circulation utilization method of nonaqueous solvents in a kind of difluorophosphate preparation process |
CN109133023B (en) * | 2017-06-27 | 2021-12-31 | 天津金牛电源材料有限责任公司 | Method for recycling non-aqueous solvent in lithium difluorophosphate preparation process |
CN112758904A (en) * | 2019-11-22 | 2021-05-07 | 多氟多化工股份有限公司 | Preparation method of lithium difluorophosphate |
WO2023120068A1 (en) * | 2021-12-21 | 2023-06-29 | 冨士色素株式会社 | Electrolyte solution |
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