A Dual-Protective Artificial Interface for Stable Lithium Metal Anodes

Constructing an advanced artificial solid electrolyte interphase (SEI) on lithium metal anodes is a promising strategy to protect Li anodes and enable them to maintain long-term cycling stability and safety. Herein, the development of a dual-protective interface as an artificial SEI with high ionic conductivity and appropriate mechanical strength to protect Li anodes from parasitic reactions and dendrite formation is reported. The dual-protective interface consists of a Prussian blue (PB) inner layer and a reduced graphene oxide (rGO) outer layer. The compact and uniform PB layer with abundant Li-ion diffusion channels facilitates fast and uniform Li-ion flux to or from the surface of the Li metal anode, guiding uniform Li deposition without dendrite formation. In addition, the flexible rGO layer on the top of the PB layer enhances the structural integrity of the PB film against severe volume change during repeated Li plating and stripping. As a result, the Li metal anodes with the dual-protective interfaces show significantly improved cycling stability with high Coulombic efficiency and dendrite-free morphology. This work provides a new strategy to enhance the stability and safety of Li metal anodes for lithium metal batteries.