Protective CaSO ₄ ‐Rich Interphase in Dual‐Intercalated Vanadium‐Based Cathodes for Zinc‐Ion Battery Performance Enhancement

The practical application of vanadium oxide‐based cathodes in high‐performance aqueous zinc‐ion batteries (AZIBs) is impeded by inherent interfacial instability, material dissolution, structural degradation, and sluggish kinetics. This study proposes a dual‐functional stabilization strategy combining dual‐ion pre‐intercalation with electrolyte optimization. This approach involves the fabrication of Ca 2+ /Na + co‐inserted CaNaVO electrodes and use of an electrolyte enriched with trace SO 4 2− , which collectively enhance the structural stability and reaction kinetics of the electrode material. Additionally, it promotes the in situ formation of a CaSO 4 ‐rich interphase layer via differential ion migration, achieving simultaneous improvement in both interfacial protection and bulk stability. Density functional theory (DFT) calculations confirm the superior electrical conductivity and accelerated ion transport of CaNaVO. The CaNaVO||Zn cell demonstrates exceptional electrochemical performance, exhibiting over 20 000 cycles at 10 A g −1 with minimal capacity decay (87.4%, only 0.00063% per cycle). Additionally, it demonstrates significant areal capacity (10 mA cm −2 , 2.3 mAh cm −2 ) and cycle life under high mass loading conditions. Notably, the battery operates effectively with a low‐concentration electrolyte (2 m ), offering significant cost advantages. This work provides an innovative approach to improving the structural stability and long‐term cycling performance of AZIBs.