An Artificial Protective Coating toward Dendrite-Free Lithium-Metal Anodes for Lithium-Sulfur Batteries

Metallic lithium (Li) has attracted considerable interest as a high-capacity anode material for the next-generation Li-metal batteries, yet its commercial availability is still challenged by its strong reactivity with electrolyte and uncontrollable growth of Li dendrites. Herein, a tuned Li anode is fabricated through a facile surface modification strategy. The LiF-dominant artificial coating layer, due to its low surface-diffusion energy barrier and excellent chemical stability against Li and electrolyte, is efficient in stabilizing the solid-electrolyte interphase (SEI) and directing homogeneous Li stripping/plating upon repeated cycling. Therefore, it significantly mitigates the corrosion reaction on the anode side and restrains the Li dendrite growth, contributing to suppressed anode degradation. As a result, the tuned Li metal achieves high symmetric cell performance, delivering a substantially decreased voltage overpotential of 37 mV over 3000 h of cycling (>4 months) at high current density (up to 8 mA cm(-2)). Moreover, the assembled high-loading Li-S pouch cells (200 mg of sulfur) using the tuned Li anode approach a high capacity (up to 189 mA h) together with good electrochemical cyclability. This work presents a viable route to regulate the Li surface chemistry and interface property for dendrite-free Li-metal anodes.