Grain-Boundary-Rich Artificial SEI Layer for High-Rate Lithium Metal Anodes

The sluggish lithium diffusion at the electrode/electrolyte interface is one of the main obstacles to achieve superior rate capability of Li metal anodes for rechargeable batteries. Herein, a dense and uniform inorganic solid electrolyte interface (SEI) layer composed of ZrO₂, Li₂O, Li₃N, and LiN_xO_y is constructed on the surface of Li metal via the spontaneous reaction between Li metal and zirconyl nitrate (ZrO(NO₃)₂) solution in dimethyl sulfoxide. The abundant grain boundaries in the artificial SEI created by the multicomponent enable the rapid diffusion of Li ions at the interface. As a result, the Li metal anode treated with zirconyl nitrate (LiZrO(NO₃)₂@Li) delivers a stable cycle performance of over 550 h at a high current density of 10 mA cm⁻² and a high areal capacity of 10 mAh cm⁻². When paired with a high-loading LiCoO₂ cathode (19 mg cm⁻²), the LiZrO(NO₃)₂@Li anode shows much enhanced rate performance and long-term cycle stability without Li dendrite formation. The construction of an inorganic SEI layer with a high density of grain boundary provides new insights for the design of high-rate and dendrite-free Li metal anodes for high-energy-density batteries.