Insulative Ion-Conducting Lithium Selenide as the Artificial Solid-Electrolyte Interface Enabling Heavy-Duty Lithium Metal Operations.

Ma, Yong; Wei, Le; Gu, Yuting; Zhao, Liang; Jing, Yixiang; Mu, Qiaoqiao; Su, Yanhui; Yuan, Xuzhou et al. · Nano Lett · 2021

basic_science · Level V

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Abstract

The deployment of Li metal batteries has been significantly tethered by uncontrollable lithium dendrite growth, especially in heavy-duty operations. Herein, we implement an <i>in situ</i> surface transformation tactic exploiting the vapor-phase solid-gas reaction to construct an artificial solid-electrolyte interphase (SEI) of Li<sub>2</sub>Se on Li metal anodes. The conformal Li<sub>2</sub>Se layer with high ionic diffusivity but poor electron conductivity effectively restrains the Li/Li<sup>+</sup> redox conversion to the Li/Li<sub>2</sub>Se interface, and further renders a smooth and chunky Li deposition through homogenized Li<sup>+</sup> flux and promoted redox kinetics. Consequently, the as-fabricated Li@Li<sub>2</sub>Se electrodes demonstrate superb cycling stability in symmetric cells at both high capacity and current density. The merits of inhibited dendrite growth and side reactions on the stabilized Li@Li<sub>2</sub>Se anode are further manifested in Li-O<sub>2</sub> batteries, greatly extending the cycling stability and energy efficiency.