Versatile Halide Ester Enabling Li Anode Stability and High Rate Capability of Lithium‐Oxygen Batteries

Li‐O2 batteries are the ultimate candidates for next‐generation high‐energy‐density battery systems. However, the main bottleneck problems of Li‐O2 batteries include the poor rate capability of cathode in practical application and the instability of Li anode. Herein, an ester‐based liquid additive, namely, 2,2,2‐trichloroethyl chloroformate, was introduced into the conventional electrolyte of Li‐O2 battery. The versatile effects of this organic molecular on oxygen cathode and Li metal anode were realized. The Li‐O2 battery showed an outstanding rate capability of 2005 mAh g−1with a remarkable reduced charge potential at a large current density of 1000 mA g−1. The positive effect of the halide ester on rate capacity are associated with the improved solubility of Li2O2 in the electrolyte and the increased diffusion rate of O2. Meanwhile, this organic molecular also promote the formation of solid electrolyte interphase layer on the surface of Li metal, which restrain the loss and volume change of Li electrode during its stripping/plating, thereby achieving a stable cycle for 900 h with a Li capacity utilization of up to 10 mAh cm−2.

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