Progress and prospects of electrolyte chemistry of calcium batteries

The increasing energy storage demand of portable devices, electric vehicles, and scalable energy storage has been driving extensive research for more affordable, more energy dense battery technologies than Li ion batteries. The alkaline earth metal, calcium (Ca), has been considered an attractive anode material to develop the next generation of rechargeable batteries. Herein, the chemical designs, electrochemical performance, and solution and interfacial chemistry of Ca²⁺ electrolytes are comprehensively reviewed and discussed. In addition, a few recommendations are presented to guide the development and evaluation of Ca²⁺ electrolytes in future.