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

The deployment of Li metal batteries has been significantly tethered by uncontrollable lithium dendrite growth, especially in heavy-duty operations. Herein, we implement an in situ surface transformation tactic exploiting the vapor-phase solid–gas reaction to construct an artificial solid-electrolyte interphase (SEI) of Li2Se on Li metal anodes. The conformal Li2Se layer with high ionic diffusivity but poor electron conductivity effectively restrains the Li/Li+ redox conversion to the Li/Li2Se interface, and further renders a smooth and chunky Li deposition through homogenized Li+ flux and promoted redox kinetics. Consequently, the as-fabricated Li@Li2Se 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@Li2Se anode are further manifested in Li–O2 batteries, greatly extending the cycling stability and energy efficiency.