Abstract: Et4NBF4/LiPF6-based electrolytes were investigated to study the effects of the electrolytes with blend solvent EC+PC+DMC on the interface characteristics of graphite electrode. Cyclic voltammetry (CV) and charge-discharge test were used to examine the compatibility between the electrolytes and graphite anode. FTIR spectroscopy was used to analyze the variational component of the solid electrolyte interface (SEI) film. The results showed that Et4NBF4 was concerned with the formation of SEI film. Irreversible capacity in the first circle remarkably reduced when the concentrations of Et4NBF4 were 0.2 and 0.5 mol·L-1, and the circle efficiencies rose to 76.0% and 81.6%, respectively. LiPF6/Et4NBF4 blend-salt electrolytes system can effectively improve the compatibility between PC-based electrolyte and graphite anode.

Key words: Li-ion battery, Eectrolyte, Blend salt, Et4NBF4, SEI film