Study on the Mixed Electrolyte of N,N-Dimethylacetamide/Sulfolane and Its Application in Aprotic Lithium–Air Batteries

Aprotic lithium–air batteries have recently drawn considerable attention due to their ultrahigh specific energy. However, the chemical and electrochemical instability of the electrolyte is one of the most critical issues that need to be overcome. To increase the stability and maintain a relatively high conductivity of the lithium ion, a mixed electrolyte of sulfolane (TMS) and N,N-dimethylacetamide (DMA) was evaluated and tested in an aprotic lithium–air battery. The physical and chemical characterizations showed that the mixed electrolyte exhibited a relatively low viscosity, high ionic conductivity and oxygen solubility, and good stability. In addition, it was found that lithium–air batteries with an optimized electrolyte composition (DMA/TMS = 20:80, % v/v) showed a better cycle life and lower charge overpotential as compared to those with electrolytes with a single solvent, either DMA or TMS.