Safe Electrolytes for Lithium-Ion Batteries Based on Ternary Mixtures of Triethylene Glycol Dimethylether, Fluoroethylene Carbonate and Non-Flammable Methyl-Nonafluorobutyl Ether

Abstract

New mixtures of triethylene glycol dimethylether, fluoroethylene carbonate and non-flammable methyl-nonafluorobutyl ether were introduced as safe electrolytes for lithium-ion batteries. It was discovered that only 10 wt% methyl-nonafluorobutyl ether was enough to ensure high safety of electrolyte and better wettability to electrodes and separator than the conventional electrolyte. The conductivity of these ternary electrolytes could reach 4.8 mS cm−1 at 25°C. Graphite/LiFePO4 coin cells with commercial electrodes were used to evaluate the electrochemical performances, and this kind of safe electrolytes could exhibit better rate and cycle performances than the conventional electrolyte. These results suggested that such ternary electrolytes composed of non-flammable hydrofluoroethers and solvents with high flash point had a great potential for practical application.