Construction of Organic–Inorganic Solid Electrolyte Interphase by Gas‐Liquid Plasma for High Performance Lithium Metal Anodes

The construction of high-quality solid electrolyte interphase (SEI) on Li metal is one of the key strategies to improve the performance of Li metal anodes. Herein, we propose a novel gas-liquid hybrid source plasma technology to construct composite SEI consisting of organic lithium methyl carbonate (LMC) and inorganic lithium nitride (Li₃N) and lithium oxide (Li₂O) on the lithium metal. Supported by the theoretical calculation, the inorganic Li₃N and Li₂O phases possess low diffusion barrier potentials, favorable for fast Li⁺ transportation, and enhanced lithophilicity. Meanwhile, the organic LMC can effectively accommodate the volume expansion of lithium metal due to its high mechanical flexibility. Accordingly, the lithium metal anode modified by plasma-made SEI has a low overpotential of 11.4 mV at 1 mAh cm^-2 for 950 h with an average Coulombic efficiency of 99.7%, superior to the unmodified Li metal anode. When coupled with LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) cathode, the assembled full cell is proven with a higher capacity retention of 87.77% after 100 cycles at 0.5 C, indicating its significantly enhanced cycling stability due to the synergistic effect between Li₃N, Li₂O, and LMC in the composite SEI. This research demonstrates that plasma is a unique method for constructing high-quality SEI to achieve enhanced lithium anodes for energy storage.