Low temperature functional electrolyte of lithium-ion secondary battery and preparation method thereof

The invention mainly relates to a method for preparing low temperature functional electrolyte of a lithium titanate (Li4Ti5O12) lithium-ion secondary battery. The functional electrolyte has the advantage that the electrolyte is suitable for high multiplying power exertion of lithium titanate material at the low temperature (-20 DEG C), thus having extreme property. The method comprises: compounding commercial electrolyte lithium salt LiPF6 and lithium salts (such as LiBF4, LiN(SO2CF3) 2 and LiODFB) with excellent low temperature property, and optimizing an electrolyte low temperature system byreducing or abandoning film-forming solvent EC with poor low temperature property and increasing low boiling point solvents such as PC, EA, THF and the like with the excellent low temperature property aiming at the characteristic of no SEI film of the Li4Ti5O12 battery. Meanwhile, a small quantity of additive is added to stabilize the interface stability of the lithium salts.