A 3D Framework with an In Situ Generated Li₃N Solid Electrolyte Interphase for Superior Lithium Metal Batteries

Abstract The practical application of lithium (Li) metal for next‐generation rechargeable batteries is still hampered by uncontrolled growth of Li dendrite and severe volume change under repeated plating/stripping. Introducing a 3D structure to reserve space for Li storage and inducing uniform plating/stripping by a lithophilic interface layer are effective strategies to solve these problems. Herein, a novel 3D composite Li anode (Fe‐N@SSM‐Li) is constructed via an in situ reaction between Li and lithiophilic Fe₂N/Fe₃N (Fe‐N) uniformly anchored on a stainless‐steel mesh (SSM). The unique lithiophilic‐conductive structure of the Fe‐N@SSM‐Li can stabilize the Li anode by effectively inducing uniform and dense deposition and confining Li deposition inside the Fe‐N@SSM‐Li to alleviate volume changes. The Fe‐N@SSM‐Li displays a distinguished electrochemical performance, with superior lifespan of 5000, 2250, and 1350 h under 1 mA cm⁻²/1 mAh cm⁻², 5 mA cm⁻²/3 mAh cm⁻², and 20 mA cm⁻²/3 mAh cm⁻² in symmetric cells, respectively. Combined with this highly stable Fe‐N@SSM‐Li, the full cells using LiFePO₄ (LFP) and S/C cathodes both show significantly improved electrochemical performances. This work provides a low‐cost and scalable strategy for the construction of high‐efficiency Li anode with a novel 3D structure, offers new insights to the research of Li metal batteries and beyond.