Highly Fluorinated Al-Centered Lithium Salt Boosting the Interfacial Compatibility of Li-Metal Batteries

Abstract

Formulating electrolytes is very powerful in protecting lithium (Li) anode from severe Li dendrites growth and pulverization. Herein, by a simple one-step and one-pot method, we innovatively synthesize a highly fluorinated (8-CF3) aluminum (Al)-centered lithium salt of lithium perfluoropinacolatoaluminate (LiFPA). The as-formulated LiFPA-based electrolytes enable practical Li/LiCoO2 (areal capacity 1.98 mAh cm–2) and Li/LiNi0.6Co0.2Mn0.2O2 (areal capacity 3.5 mAh cm–2) Li metal batteries (LMBs) with good cycling stability. On the one hand, LiFPA salt can reduce electrolyte surface tension, improve electrolyte wettability, and ultimately suppress Li dendrites growth. On the other hand, the LiFPA salt will facilitate the formation of a protective passivating interphase layer on both electrodes. Our work states the importance of synthesizing of lithium salts with good interfacial compatibility for high performance LMBs.