Facile Electrodeposition Method for Constructing Li2S as Artificial Solid Electrolyte Interphase for High‐Performance Li Metal Anode

Abstract Designing current collectors and constructing efficient artificial solid electrolyte interphase (SEI) layers are promising strategies for achieving dendrite‐free Li deposition and practical applications in Li metal batteries (LMBs). Electrodeposition is advantageous for large‐scale production and allows the direct formation of current collectors without binders, making them immediately usable as electrodes. In this study, an adherent Cu 2 S thin‐layer on Cu foil is synthesized through anodic electrodeposition from a Na 2 S solution in a one‐step process, followed by the generation of Li 2 S layers as artificial SEI layers via a conversion reaction (3DLi 2 S‐Cu foil). The Li 2 S layers move from the 3D Cu surface to the deposited Li surface, facilitating uniform and dense Li deposition. The 3DLi 2 S‐Cu foil structure demonstrates stable cycling performance over 350 cycles in an asymmetric cell, with a capacity of 1 mAh cm −2 at 1 mA cm −2 . Moreover, symmetric cells with 5 mAh cm −2 of deposited Li exhibit a stable cycle life for over 1200 h. When paired with commercial LiFePO 4 (LFP), the full cells show substantially enhanced cyclability, regardless of the amount of deposited Li. This study provides new insights into the construction of artificial SEIs for facilitating commercial applications.