Heterogeneous Nitride Interface Enabled by Stepwise‐Reduction Electrolyte Design for Dense Li Deposition in Carbonate Electrolytes

Stable solid electrolyte interphase (SEI) with high Li+‐ion conductivity is desperately desired for lithium (Li) metal anodes. However, it remains challenging to build a robust SEI rationally for the Li‐metal anodes in carbonate electrolytes. Herein, a heterogeneous nitride‐rich SEI that consists of organic nitrides on the surface and inorganic nitrides inside by stepwise‐reduction electrolyte design is constructed. The heterogeneous structure endows SEI with the capability to capture and distribute Li+ on the surface and facilitate internal Li+ transportation, leading to the redistributed Li+ flux and uniform Li electrodeposition. With the newly‐formulated carbonate electrolyte, Li||Cu cells deliver a high Coulombic efficiency of 98.0% after 300 cycles at 0.5 mA cm‐2 and 0.5 mAh cm‐2. Meanwhile, superb cycling stability is also determined with full Li‐metal cells using LiNi1/3Mn1/3Co1/3O2 and high‐loading LiFePO4 (12.0 mg cm−2) cathodes. This study provides a promising strategy to regulate the SEI components and stabilize the Li anodes by rational electrolyte design. A new carbonate electrolyte is formulated, in which LiNO3 additive and DMA solvent can be reduced one by one during the Li plating process, leading to the formation of a heterogeneous nitride solid electrolyte interphase on the surface of Li‐metal anodes. With the as‐designed electrolyte, the Li||Li, Li||Cu, Li||NCM111, and Li||LiFePO4 (LFP) cells demonstrate significantly‐improved electrochemical performance.