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

Abstract 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─O 2 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−RuO 2 ─O 2 battery maintains 160‐cycle cycle‐life at a high current density of 0.5 A g −1 .