Decreasing Interfacial Pitfalls with Self‐Grown Sheet‐Like Li2S Artificial Solid‐Electrolyte Interphase for Enhanced Cycling Performance of Lithium Metal Anode

Abstract Constructing a 3D composite Li metal anode (LMA) along with the engineering of artificial solid electrolyte interphase (SEI) is a promising strategy for achieving dendrite‐free Li deposition and high cycling stability. The nanostructure of artificial SEI is closely related to the performance of the LMA. Herein, the self‐grown process and morphology of in situ formed Li 2 S during lithiation of Cu x S is studied systematically, and a large‐sized sheet‐like Li 2 S layer as an artificial SEI is in situ generated on the inner surface of a 3D continuous porous Cu skeleton (3DCu@Li 2 S‐S). The sheet‐like Li 2 S layer with few interfacial pitfalls (Cu/Li 2 S heterogeneous interface) possesses enhanced diffusion of Li ions. And the continuous porous structure provides transport channels for lithium‐ion transport. As a result, the 3DCu@Li 2 S‐S presents a high Coulombic efficiency (99.3%), long cycle life (500 cycles), and high‐rate performance (10 mA cm −2 ). Furthermore, Li/3DCu@Li 2 S anode fabricated by thermal infusion method inherits the synergistic advantages of sheet‐like Li 2 S and continuous porous structure. The Li/3DCu@Li 2 S anode shows significantly enhanced cycling life in both liquid and solid electrolytes. This work provides a new concept to design artificial SEI for LMA with high safe and high performance.