Multi-dimensional hybrid flexible films promote uniform lithium deposition and mitigate volume change as lithium metal anodes

Lithium metal is the ultimate anode material for next-generation high-energy batteries. Yet, the practical application of lithium metal anodes is limited by the formation of Li dendrites and large volume changes. Herein, an effective multi-dimensional hybrid flexible film (MD-HFF) composed of iodine ion (0 dimension), CNTs (1 dimension) and graphene (2 dimensions) is designed for regulating Li deposition and mitigating volume changes. The multi-dimensional components serve separate roles: (1) iodine ion enhances the conductivity of the electrode and provides lithiophilic sites, (2) CNTs strengthen interlaminar conductance and mechanical strength, acting as a spring in the layered structure to alleviate volume changes during Li plating and stripping and (3) graphene provides mechanical flexibility and electrical conductivity. The resulting MD-HFF material supports stable Li plating/stripping and high Coulombic efficiency (99%) over 230 cycles at 1 mA cm(-2) with a deposition capacity of 1 mAh cm(-2). Theoretical calculations indicate that LiI contributes to the lateral growth of Li on the MD-HFF surface, thereby inhibiting the formation of Li dendrites. When paired with a typical NCM811 cathode, the assembled MD-HFF parallel to NCM811 cell exhibit improved capability and stable cycling performance. This research serves to guide material design in achieving Li anode materials that do not suffer from dendrite formation and volume changes. (C) 2021 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

Automated summary

This study presents a multi-dimensional hybrid flexible film (MD-HFF) designed to regulate lithium deposition and mitigate volume changes, resulting in stable lithium plating/stripping with high Coulombic efficiency. The various components in MD-HFF play separate roles and together contribute to the superior performance of the material.