A kind of preparation method of difluorophosphoric acid and lithium difluorophosphate

Abstract

The invention relates to a preparing method of difluorophosphoric acid and lithium difluorophosphate. The preparing method of lithium difluorophosphate comprises the following steps of 1, carrying outa reaction between dichloro phosphate and a fluorinated reagent to prepare the difluorophosphoric acid, wherein the fluorinated reagent is AsF3, NH4F, NH4HF2 and / or MFx, for MFx, x is equal to 1 or 2or 3, and M is hydrogen, alkali metal, alkaline-earth metal or transition metal; 2, carrying out a reaction between difluorophosphoric acid and a lithium source material in a non-aqueous agent. According to the preparing method of lithium difluorophosphate, dichloro phosphate, the fluorinated reagent and the lithium source material serve as raw materials to carry out the reactions to prepare lithium difluorophosphate, and the raw materials are wide in source and low in cost; a fluoridation reaction and a substitution reaction of the lithium source material easily take place, the side reactionis small, a crude product of lithium difluorophosphate with few impurities is conveniently obtained under the condition of a high conversion rate, and thus good conditions are created for obtaining high-quality products of lithium difluorophosphate at low cost.

Description

technical field

[0001] The invention belongs to the field of lithium ion battery additives, and in particular relates to a preparation method of difluorophosphoric acid and lithium difluorophosphate. Background technique

[0002] In recent years, lithium-ion power batteries and energy storage batteries have become one of the research hotspots in the field of new energy. At present, the anode materials of lithium-ion power batteries are mainly lithium iron phosphate and nickel-cobalt-manganese ternary materials, and the electrolyte is mainly a liquid electrolyte system composed of lithium hexafluorophosphate and carbonate organic solvents.

[0003] In the ternary positive electrode material system, adding an appropriate amount of lithium difluorophosphate can reduce the internal resistance of the battery, and form a protective film on the positive electrode of the battery, so that the cycle performance of the battery is significantly improved; at the same time, lithium iron p...

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