Li₃N-Enriched Solid Electrolyte Interphase Derived From Interfacial Catalysis Toward High-Performance Lithium Metal Batteries.

Abstract

The commercialization of lithium metal batteries (LMBs) is fundamentally challenged by Li dendrite growth, which originates from an unstable solid electrolyte interphase (SEI). Engineering a Li₃N-enriched SEI is highly desirable for achieving high conductivity and mechanical strength, but the kinetic barrier of the LiNO₃-to-Li₃N conversion remains a major obstacle. Here, we report a catalytic approach to engineer Li₃N-enriched SEI layers by accelerating LiNO₃ reduction using transition metal single-atom catalysts supported on nitrogen-doped carbon (M/NC, M = Cr, Mn, Fe, Co, Ni, Zn). Among them, Co/NC exhibits the highest catalytic activity, leading to an SEI with significantly enhanced mechanical robustness and ionic transport. Theoretical calculations reveal that the superior performance of Co/NC stems from the minimal energy difference between its frontier molecular orbitals and those of the key LiNO intermediate, facilitating the electron transfer process. Consequently, the symmetric battery using Co/NC catalyst achieves exceptional cyclability for over 2500 h (1 mA cm^-2, 1 mAh cm^-2). When applied in full cells, the Co/NC-modified current collector also yields a dramatically prolonged cycle life. This work underscores the profound role of interfacial catalysis in designing high-performance SEI for practical LMBs.