Strategies for improving cathode electrolyte interphase in high-performance dual-ion batteries.

Dual-ion batteries (DIBs) offer high energy density due to the ability to intercalate both anions and cations, thereby increasing the cutoff voltage and battery capacity. Graphite, with its ordered layered structure and cost-effectiveness, is commonly employed as the cathode material for DIBs. However, the discharge capacity of graphite cathodes is relatively low, and their cycling stability is poor, limiting the practical applications of DIBs. The formation of cathode electrolyte interphase (CEI) on the graphite cathode surface is closely related to anion behavior. Constructing a stable cathode electrolyte interface is crucial for improving the stability of anion storage. Therefore, we introduce a series of strategies to enhance the quality of the CEI layer, including additives, binders, main salts or solvents, high-concentration electrolytes, doping elements, artificial CEI, and graphite surface modifications. These strategies improve the CEI by enhancing anion transport rates, increasing anion solvation capabilities, and improving the structural stability of graphite cathodes, which is of profound significance for increasing the capacity and stability of DIBs. This review provides inspiration for future CEI research, encouraging further exploration of resources of CEI components and improvement strategies to further promote the development of DIBs technology.