Lithiophilic low-valence-state metal oxides enable high-performance 3D lithium metal anodes

Li metal anodes (LMAs) are deemed as a pragmatic approach for the next-generation high-energy-density devices. Yet, their implementation is plagued by low Coulombic efficiency and inferior cycling stability. Herein, we explore a 3D LMA design strategy through the single-displacement reaction with metal oxides. By incorporating lithiophilic nickel oxides with various valence states into the anode fabrication process, we observe that NiO consumes a small amount of Li while Ni₂O₃ opposes. Upon the charging/discharging procedures, LN2N effectively regulates Li plating/stripping and stabilizes the solid electrolyte interface to deliver great Li electrochemistry. In contrast, the partially available LN3N due to the overreaction with Li delivers poor electrochemical performance. In long-term testing of full cells, LN2N demonstrates an high coulombic efficiency (CE) of 99 % and stable cycling behavior for LFP and NCM cathodes at a 1C rate. This work brings to light the application of metallic compounds at different valence states as lithiophilic sites for practical lithium metal batteries.