Lithium Salt Dissociation Promoted by 18‐Crown‐6 Ether Additive toward Dilute Electrolytes for High Performance Lithium Oxygen Batteries

Abstract

AbstractLithium‐oxygen batteries (LOBs) are well known for their high energy density. However, their reversibility and rate performance are challenged due to the sluggish oxygen reduction/evolution reactions (ORR/OER) kinetics, serious side reactions and uncontrollable Li dendrite growth. The electrolyte plays a key role in transport of Li+ and reactive oxygen species in LOBs. Here, we tailored a dilute electrolyte by screening suitable crown ether additives to promote lithium salt dissociation and Li+ solvation through electrostatic interaction. The electrolyte containing 100 mM 18‐crown‐6 ether (100‐18C6) exhibits enhanced electrochemical stability and triggers a solution‐mediated Li2O2 growth pathway in LOBs, showing high discharge capacity of 10 828.8 mAh gcarbon−1. Moreover, optimized electrode/electrolyte interfaces promote ORR/OER kinetics on cathode and achieve dendrite‐free Li anode, which enhances the cycle life. This work casts new lights on the design of low‐cost dilute electrolytes for high performance LOBs.