Tuning Li Stripping/Plating Routes by Crystalline Engineering of LiMg Alloys for High-Energy–Density Li-Metal Batteries

Commercial applications of Li-metal batteries are hindered by structure challenges and safety concerns of metallic Li anodes. Regulating Li stripping/plating routes is critical for restraining volume-stress change and realizing dendrite-free deposition. In this work, it is found that α-LiMg alloy exhibits higher adsorption capability and lower migration barrier to Li ions than the pure Li metal. On this basis, the reversible phase transformation between β-LiMg and α-LiMg alloys, accompanied by preferred migration paths, facilitates homogeneous and fast stripping/plating cycles. Systematic studies disclose the correlation between phase transformation facet adjustment and Li migration path optimization, confirming β-LiMg alloy electrodes with excellent electrochemical properties. Two representative Li-metal battery systems, Li─S and Li─O₂ batteries using β-LiMg alloy anodes exhibit significantly improved electrochemical performance, especially long-term cyclability, compared to their counterparts in the pure Li metal batteries. A typical β-LiMg─S/C battery shows a high-capacity retention of 80.6% after 600 cycles at 1.0 A g⁻¹, while a β-LiMg−RuO₂─O₂ battery maintains 160-cycle cycle-life at a high current density of 0.5 A g⁻¹.