Constructing LiF/Li2CO3-rich heterostructured electrode electrolyte interphases by electrolyte additive for 4.5 V well-cycled lithium metal batteries

The cycling performance of promising high-voltage Li||LiNi0.8Co0.1Mn0.1O2 (NCM811) batteries is deter-mined by the interfacial stability between electrodes and electrolyte. However, it is challenging to achieve them under high voltage. Herein, we stabilized 4.5 V Li||NCM811 batteries via electrolyte engi-neering with pentafluorostyrene (PFBE) as the additive. PFBE contributes to the formation of highly Li+ conductive and mechanically robust LiF/Li2CO3-rich heterostructured interphases on NCM811 cathode and Li metal anode (LMA) surfaces. Such electrode-electrolyte interphases (EEIs) obviously alleviate irre-versible phase transition, microcracks induced by stress accumulation and transition metal dissolution in the Ni-rich layered cathode. Meanwhile, the growth of Li dendrites on the LMA surface is effectively con-trolled. As expected, 4.5 V Li||NCM811 batteries sustain a capacity retention rate of 61.27% after 600 cycles at 0.5 C (100 mA g-1). More importantly,-6.69 Ah Li||NCM811 pouch cells with such electrolytes could represent a stable energy density of-485 Wh kg-1 based on all cell components.& COPY; 2023 Science China Press. Published by Elsevier B.V. and Science China Press. All rights reserved.