Decreasing Interfacial Pitfalls with Self-Grown Sheet-Like Li 2 S Artificial Solid-Electrolyte Interphase for Enhanced Cycling Performance of Lithium Metal Anode.

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.