Local Strong Solvation Electrolyte Trade‐Off between Capacity and Cycle Life of Li‐O 2 Batteries

Li‐O 2 batteries are promising energy storage devices with ultra‐high theoretical energy density. However, in practice they show severe capacity fading and limited cycle life, meaning that more suitable electrolytes are urgently needed. Here, solvents are combined with high donor number and low donor number, and a Li salt to produce a new local strong solvation effect electrolyte. High discharge capacity and good cycling performance are achieved when the optimized electrolyte is used in a Li‐O 2 battery. The optimized electrolyte inhibits side reactions within the battery and facilitates stable solid electrolyte interphase film formation on the surfaces of Li anode. This work opens a new route for the design of high‐performance electrolytes to increase both capacity and cycle life of Li‐O 2 batteries.