Elevated-Temperature Electrolytes for Li-Ion Batteries

Research progress and prospects of electrolytes used at elevated-temperature for lithium-ion batteries are summarized in this paper. The deficiency of current commercial electrolytes at high temperature is clarified according to the chemical stability of solutes and solvents. Some ideas are proposed to develop the thermal stability of lithium salts, ionic liquids and flame retardant additives. The deficiencies of the present lithium salts can be overcome through the modification of functional group or the structure composite, and new kind of lithium salt can be developed for elevated-temperature lithium ion battery. Non-carbonic acid ester showed poor performance when it was used alone, ionic liquids showed poor compatibility with commonly used anode and cathode materials. The most possible way for the application of high-temperature electrolyte is the blend of carbonates and flame retardants. Better flame retardant can be achieved by introducing flame-retardant elements into phosphate ester or modifying part of the functional group, which will improve the performance of electrolyte in high temperature.