Stabilizing the Interphase in an Ultra-High-Nickel Cathode Enabling High-Performance Lithium-Ion Batteries

High-nickel (Ni ≥ 90%) cathodes which have a high specific capacity hold great potential for next-generation lithium-ion batteries (LIBs). However, their practical application is restricted by their high interfacial reactivity because of the presence of residual lithium (Li) compounds on the surface. Herein, the LiNi_0.9Co_0.06Mn_0.04O₂ (NCM90) cathode is surface-modified with sulfur (S) via a simple and feasible dry mixing and low-temperature heat treatment, converting the residual lithium compound on the surface into inactive lithium sulfate (Li₂SO₄). This induces the formation of a stable inorganic enriched electrode-electrolyte interface on the cathode surface and inhibits the occurrence of side reactions, ultimately inhibiting lattice collapse and the dissolution of transition metal ions. After modifying, the capacity retention rates of NCM90/Li and NCM90/graphite cells are both greatly enhanced after long cycling. This work provides a new idea for the rational design of the electrode-electrolyte interface of high-nickel cathodes.