Forming robust and highly Li-ion conductive interfaces in high-performance lithium metal batteries using chloroethylene carbonate additive

Developing high-rate Li metal batteries (LMBs) is challenging because of dendrite growth and irreversible parasitic reactions of the Li metal. Herein, a robust and highly ion-conductive solid electrolyte interphase (SEI) layer is designed on a Li metal anode and a Ni-rich layered cathode by incorporating chloroethylene carbonate (ClEC) as an additive in fluoroethylene carbonate-based electrolytes. ClEC induces the formation of LiCl, which facilitates Li-ion diffusion in the robust LiF-rich SEI layer, thereby improving the cycle stability of the Li metal anode and suppressing microcracking of the Ni-rich layered cathode, especially during charging and discharging at high current densities. By using the newly developed combination of electrolyte solution, an LMB featuring the Li[Ni${}_{0.78}$Co${}_{0.1}$Mn${}_{0.12}$]O${}_2$ cathode (2.3 mAh cm${}^{-2}$, 0.1 C) affords a superior capacity retention of 80.2% over 400 cycles at high charge and discharge current densities of 2.0 C (3.6 mA cm${}^{-2}$) and 5.0 C (9.0 mA cm${}^{-2}$). This study provides insights into the use of ClEC as an electrolyte additive and highlights the importance of constructing robust and highly ion-conductive interfaces on both Li metal anodes and Ni-rich cathodes for high-performance LMBs. (© 2023 The Authors. Advanced Energy and Sustainability Research published by Wiley‐VCH GmbH)