Anion-Reduction-Catalysis Induced LiF-Rich SEI Construction for High-Performance Lithium-Metal Batteries

Abstract

The practical application of lithium-metal batteries (LMBs) remains impeded by uncontrollable Li dendrite growth and unstable solid-state electrolyte interphase (SEI) on lithium-metal anodes. Constructing the inorganic-rich SEI is considered as an effective strategy to realize the dense Li deposition and inhibit interfacial side reactions, thereby improving the lifespans of LMBs. Herein, an anion-reduction-catalysis mechanism is proposed to design a LiF-rich SEI utilizing 2D tellurium (Te) nanosheets as catalysts, which are homogenously implanted on the substrate. Lithiophilic Te nanosheets can induce uniform Li nucleation and deposition through in situ lithiation reactions, while the resulting product Li₂Te can reduce the energy barrier for anion decomposition and promote the generation of LiF in the SEI. Consequently, Li dendrite growth and interfacial side reactions are effectively suppressed, enabling long-cycle-life LMBs. The Te-modified electrode in half-cells delivers superior cycle life exceeding 500 cycles and a high average Coulombic efficiency of 97.8% at 5 mAh cm⁻². The high-energy-density (405 Wh kg⁻¹) pouch cells pairing the Te-modified Li anodes with high-mass-loading LiNi_0.9Co_0.05Mn_0.05O₂ (NCM90) cathodes exhibit stable cycling performance with a high average Coulombic efficiency of 99.3% in carbonate electrolytes. This work provides a promising anion catalyst design for LiF-rich SEI and paves the way for developing high-energy-density LMBs.