253 results about "Difluorophosphoric acid" patented technology

A difluorophosphate salt, which is expensive and not readily available, can be produced with a high purity readily and efficiently from inexpensive and readily available materials. A nonaqueous electrolyte secondary battery that exhibits low-temperature discharge and heavy-current discharge characteristics and high-temperature preservation and cycle characteristics without impairing the battery safety. A hexafluorophosphate salt is reacted with a compound having a bond represented by the following formula (1) in the molecule:

Si—O—Si  (1)

A nonaqueous electrolyte used for nonaqueous electrolyte secondary batteries including a negative electrode and a positive electrode that can occlude and discharge ions, and a nonaqueous electrolyte is prepared from a mixture obtained by mixing at least one nonaqueous solvent, a hexafluorophosphate salt and a compound having a bond represented by the following formula (1), and removing low-boiling compounds newly formed in the system, the low-boiling compounds having a lower boiling point than that of the compound having the bond represented by the formula (1):

Si—O—Si  (1)

The invention discloses a high-capacity lithium-ion battery electrolyte of considering high-and-low temperature performance. The electrolyte comprises a non-aqueous solvent, lithium hexafluorophate, a negative film-forming additive, an inflatable inhibition additive and a low-impedance additive, wherein the negative film-forming additive is prepared from fluoroethylene carbonate which accounts for 3%-15% of total mass of the electrolyte; the inflatable inhibition additive is prepared from one or two of 1,3-propene sultone or anhydride compounds which account for 0.3%-5% of total mass of the electrolyte; and the low-impedance additive is prepared from one or two of lithium difluorophosphate and difluoride phosphate lithium oxalate which account for 0.2%-3% of total mass of the electrolyte. The electrolyte is suitable for a high-nickel positive electrode and silicon-carbon composite negative electrode lithium-ion battery; the high-temperature storage performance and the low-temperature discharge performance of the lithium-ion battery are improved while the room-temperature cycle performance is considered; and meanwhile, the invention further provides a preparation method of the electrolyte and the high-capacity lithium-ion battery of using the electrolyte.

A difluorophosphate effective as an additive for a nonaqueous electrolyte for secondary battery is produced by a simple method from inexpensive common materials.

The difluorophosphate is produced by reacting lithium hexafluorophosphate with a carbonate in a nonaqueous solvent. The liquid reaction mixture resulting from this reaction is supplied for providing the difluorophosphate in a nonaqueous electrolyte comprising a nonaqueous solvent which contains at least a hexafluorophosphate as an electrolyte lithium salt and further contains a difluorophosphate. Also provided is a nonaqueous-electrolyte secondary battery employing this nonaqueous electrolyte.

The invention discloses a high-voltage rate electrolyte with high-and-low temperature performance and a lithium ion battery using the electrolyte. The electrolyte comprises a non-aqueous solvent, a lithium salt dissolved in the non-aqueous solvent and additives, wherein the non-aqueous solvent comprises propylene carbonate (PC) and linear carboxylic ester; and the additives comprise citraconic anhydride, lithium difluorophosphate (LiPO<2>F<2>), fluoroethylene carbonate, ethylene sulfate and 1, 2-di(2-cyanoethoxyl)ethane. By applying the synergistic effect generated by the solvent system and the additive optimization combination to the lithium ion battery, excellent cycle life, low-temperature discharge characteristic and high-temperature storage characteristic of the battery still can be maintained at high-voltage rate.

A silicon carbon lithium ion battery electrolyte and a silicon carbon lithium ion battery using the same belong to the field of lithium ion battery materials. The electrolyte comprises a film-formingadditive accounting for 8% to 15% by weight of the total weight of the electrolyte. The film-forming additive comprises a phosphate ester/phosphite ester compound, fluoroethylene carbonate (FEC), ethylene sulfate (DTD) and lithium difluorophosphate (LiPO2F2). The electrolyte has excellent cycle performance. The phosphate ester/phosphite ester compound has chemical structural formulas shown by theformulas (I) and (II) which are described in the specifications.

A non-aqueous electrolyte for a battery comprises a non-aqueous solvent containing a specified cyclic phosphazene compound and a specified difluorophosphate compound, a specified aniline derivative and a support salt.

A lithium secondary cell which comprises a positive electrode and a negative electrode which have a specific composition and specific properties and a nonaqueous electrolytic solution containing a cyclic siloxane compound represented by the formula (1), a fluorosilane compound represented by the formula (2), a compound represented by the formula (3), a compound having an S-F bond, a nitric acid salt, a nitrous acid salt, a monofluorophosphoric acid salt, a difluorophosphoric acid salt, an acetic acid salt, or a propionic acid salt in an amount of at least 10 ppm of the whole nonaqueous electrolytic solution. The lithium secondary cell has a high capacity, long life, and high output. In the general formula (1), R<1> and R<2> each is a C1-12 organic group; and n is an integer of 3-10. In the general formula (2), R<3> to R<5> each is a C1-12 organic group; x is an integer of 1-3; and p, q, and r each is an integer of 0-3, provided that 1=p+q+r=3. In the general formula (3), R<6> to R<8> each is a C1-12 organic group; and A is a group constituted of H, C, N, O, F, S, Si, and/or P.

The invention provides a non-aqueous electrolyte and a lithium ion battery. The non-aqueous electrolyte comprises a solvent, an electrolyte lithium salt and a functional additive, and the functional additive comprises pentafluorophenyl vinyl sulfonate, 3-trifluoromethyl-5-methoxybenzonitrile and lithium difluorophosphate. When the electrolyte disclosed by the invention is applied to the lithium ion battery of a nickel-cobalt-manganese ternary material/graphite system, the high-voltage resistance of the lithium ion battery is improved, and the rate capability, the normal-temperature cycle, thehigh-temperature cycle and the high-temperature storage performance of the lithium ion battery are remarkably improved.

The invention discloses composite lithium ion battery electrolyte and a lithium ion battery comprising the same. The composite lithium ion battery electrolyte comprises an organic solvent, lithium salt and an additive. The organic solvent is at least two of propylene carbonate (PC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), allyl ethyl carbonate (AEC), allylmethyl carbonate (AMC) and the like; and the additive is selected from at least two of unsaturated carbonate, sulfur-containing organic matters, lithium borate dioxalate, lithium difluorophosphate and fluoro-imide salt. For the respective physical and chemical characteristics of the organic solvent and the additive, the types of the additive are screened and combined, by adjustment on an electrolyte additive, the ratio by which respective advantages can be played and respective shortcomings can also be suppressed is found out, the high-voltage capacity of the battery is improved, and the cycle life of the battery is prolonged.

The invention discloses a lithium ion battery electrolytic solution, which comprises a film-forming additive, wherein the film-forming additive comprises vinylene carbonate, ethylene sulfate, 1,3-propane sultone and lithium difluorophosphate, wherein the vinylene carbonate accounts for 0.2%-3% of the total mass of the electrolytic solution, the ethylene sulfate accounts for 0.5%-5% of the total mass of the electrolytic solution, the 1,3-propane sultone accounts for 0.2%-3% of the total mass of the electrolytic solution, and the lithium difluorophosphate accounts for 0.2%-2% of the total mass of the electrolytic solution. According to the invention, vinylene carbonate and ethylene sulfate in the electrolytic solution form a stable and compact SEI film on the surface of the negative electrode of the battery in the formation, charging and discharging processes, and 1,3-propane sultone and lithium difluorophosphate form a passive film on the surface of the positive electrode, so that the high-temperature gas production performance of the battery is improved, the damage to the negative electrode due to dissolution of positive electrode transition metal elements in the quick charge cycleprocess is inhibited, the film forming structure of the positive electrode and the negative electrode can be improved, the side reaction is reduced, and the battery is ensured to have good high-ratecharging performance and cycle life.

The invention discloses a method for preparing lithium difluorophosphate. The method comprises the following steps: dissolving lithium carbonate and lithium hexafluorophosphate in an aprotic solvent, uniformly mixing above substances and the solvent, filling a closed container with the obtained solution, carrying out a high-temperature and high-pressure reaction for a certain time, carrying out rotary evaporation to remove the solvent, and purifying the obtained reaction product through a washing process to obtain highly-pure lithium difluorophosphate. The method for preparing the lithium difluorophosphate through adopting a solvothermal technology has the advantages of realization of high-temperature rapid preparation of the lithium difluorophosphate, small dosage of the solvent, high easiness in purification, and very high purity of the target product.

A non-aqueous electrolyte for a battery comprises a non-aqueous solvent containing a specified cyclic phosphazene compound and a specified difluorophosphate compound, a dicarboxylic anhydride compound having a cyclic structure and a support salt.

The invention discloses a method for preparing lithium difluorophosphate. The synthesis principle is that difluorophosphate is subjected to a contact reaction with lithium hydroxide in a non-aqueous solvent, or difluorophosphate contacts is subjected to the contact reaction with lithium carbonate in the non-aqueous solvent, and specifically a reaction equation is that HPO2F2+LiOH=LiPO2F2+H2O, or 2HPO2F2+Li2CO3=2LiPO2F2+H2O+CO2. According to the method, difluorophosphate and lithium carbonate or lithium hydroxide are adopted as main raw materials, lithium hexafluorophosphate which is common inthe prior art is not used, and thus the reaction cost is reduced; in addition, in the preparation process, no harmful gas such as a fluorine gas is used, and the reaction process is easy to control, high in security coefficient and low in equipment cost; the reaction process is a solid-liquid reaction, the raw materials are target products are both free of gas, the raw materials and the products are easy in purity control and convenient to transport, and the raw material utilization rate is high, so that the cost can be lowered.

Provided is a method for producing difluorophosphate which is characterized by obtaining the difluorophosphate by reacting at least one salt, as a raw material, selected from a halide salt, a carbonate, a phosphate, a hydroxide and an oxide of an alkali metal, an alkali earth metal or an onium with a difluorophosphoric acid in the difluorophosphoric acid, then separating a precipitate from the difluorophosphoric acid by solid liquid separation, the precipitate being precipitated by crystallization operation in the difluorophosphoric acid, and distilling the difluorophosphoric acid contained in the precipitate.

The invention relates to a preparation method of lithium phosphate difluoride, in particular to a method for producing industrially and economically-superior lithium phosphate difluoride for producingnonaqueous electrolyte batteries. The preparation method of the lithium phosphate difluoride at least comprises the following steps: (1) performing a reaction on lithium halide, phosphorus pentahalide and lithium hexafluorophosphate to obtain tetra-halogen lithium phosphate difluoride; (2) making tetra-halogen lithium phosphate difluoride react with a substance containing active oxygen to obtainlithium phosphate difluoride.

The invention discloses a preparation method of high purity difluorophosphate. The preparation method comprises the following steps: dissolving meta-phosphoric acid in alcohol, then introducing hydrogen fluoride into the alcohol to carry out fluorination reactions to obtain monofluorophosphoric acid, reacting monofluorophosphoric acid with phosphorus oxyfluoride gas to obtain difluorophosphoric acid, then reacting difluorophosphoric acid with alkali metals or alkali-earth metal halides, and separating the reaction products to obtain high purity difluorophosphate. The preparation method has the advantages that the raw materials are cheap and easily-available, a homogenous reaction technology is adopted, thus the reaction speed is greatly increased; during the reaction process, the excess raw materials and solvents can be separated, recovered, and reused through fractionation, thus the amount of generated wastes is reduced; and during the whole process, no water is generated, so the product will not be hydrolyzed. The high purity difluorophosphate can be used to produce electronic chemicals.

The invention discloses a preparation method of difluorophosphoric acid alkali metal salt. In the method, the difluorophosphoric acid alkali metal salt is produced through a reaction of hexafluorophosphates of alkali metals and corresponding phosphates of the alkali metals in a solid phase or in a non-aqueous solvent, wherein the reaction equation is MPF6+M3PO4=2MPO2F2+2MF (M=Li, Na, K, Rb, Cs), the molar ratio of MPF6 to M3PO4 is 0.8-1.5:1, preferably 1.1-1.2:1, namely, the hexafluorophosphates of alkali metals is excessive properly to ensure reaction of the phosphates to be carried completely. The method can be used for preparing the difluorophosphoric acid alkali metal salt under safe situations, thereby improving safety of the preparation process and ensuring safety of preparation operators. The difluorophosphoric acid alkali metal salt is produced through a reaction of the hexafluorophosphates and the phosphates of the alkali metals, and the target product can be produced whether the reaction is carried out in solid phases or liquid phases under mild conditions without dangerous gas raw materials and generation of acidic gas or water which may damage performances of an electrolyte.

The invention relates to an electrolyte functional additive for a lithium ion battery, a lithium ion battery electrolyte and a lithium ion battery, and belongs to the technical field of lithium ion batteries. The electrolyte functional additive for the lithium ion battery is prepared from the following components in parts by weight: 0.2-2 parts of vinylene carbonate; 0.5-2.5 parts of ethylene sulfate; 0.2-1 part of lithium difluorophosphate; 0.2-1 part of a film-forming agent; and 0.5-2.5 parts of fluoroethylene carbonate. The film-forming agent is at least one of tris(trimethylsilane) borateand tris(trimethylsilane) phosphate. When the electrolyte functional additive for the lithium ion battery is used for the lithium ion battery made of a high-capacity ternary positive electrode material, excellent SEI films can be formed on the surfaces of the positive electrode and negative electrode of the lithium ion battery, so that direct contact between an electrolyte and the surface of the positive electrode can be effectively prevented, meanwhile, the dissolution of metal ions is reduced, and the cycle performance of the battery is obviously improved.

The invention provides a lithium ion battery electrolyte for a high-voltage system. The lithium ion battery electrolyte comprises a non-aqueous organic solvent, an electrolyte lithium salt and an additive; the additive comprises a trimethylsilane cyclic phosphate compound; R1 is at least one of a hydrogen atom, a halogen atom, an alkyl group, an alkylene group, a cyano group or a haloalkane; and R2 is at least one of a hydrogen atom, a halogen atom, an alkyl group, an alkylene group, a cyano group or a haloalkane. According to the lithium ion battery electrolyte for the high-voltage system, lithium difluorophosphate and the trimethylsilane cyclic phosphate compound are used as composite functional additives of the electrolyte; through the synergistic effect of the trimethylsilane cyclic phosphate compound and the lithium difluorophosphate, a compact and stable protective film (CEI film) can be formed on the surface of the positive electrode of the lithium ion battery, so that the high-temperature storage performance and high-temperature cycle performance of the lithium ion battery under high voltage are effectively improved.