Preparation method of lithium bis(oxalate)borate and lithium tetrafluoroborate

The invention relates to a preparation method of electrolyte lithium salt used in the lithium ion battery industry, in particular to a preparation method of lithium bis(oxalate)borate and lithium tetrafluoroborate. The preparation method of the lithium bis(oxalate) borate and lithium tetrafluoroborate comprises the steps that (1) lithium difluorooxalate borate is dissolved in an inert atmosphere to form a solution; (2) an ionic coordination catalyst is added into the solution at the temperature of 0-105 DEG C and the pressure of 101-150 kpa to form a reaction product comprising the lithium bis(oxalate)borate and the lithium tetrafluoroborate. The preparation method of the lithium bis(oxalate) borate and lithium tetrafluoroborate has the advantages that the reaction rate is fast, the reaction condition is simple, the operation is convenient, and the yield is high; the raw material cost can be reduced, the material consumption and waste generation are reduced, the utilization rate, product yield and purity of r