Cu²⁺ Intercalation and Structural Water Enhance Electrochemical Performance of Cathode in Zinc-Ion Batteries

This study investigates the performance of Cu-intercalated V₃O₇·H₂O (CuVOH) as a cathode material for aqueous zinc-ion batteries (AZIBs). DFT calculations were conducted to explore the effects of Cu2+ incorporation and structural water on the electrochemical performance of VOH. The results indicated that Cu2+ and structural water enhance Zn2+ diffusion by reducing electrostatic resistance and facilitating faster transport. Based on these insights, CuVOH nanobelts were synthesized via a one-step hydrothermal method. The experimental results confirmed the DFT predictions, demonstrating that CuVOH exhibited an initial discharge capacity of 336.1 mAh g−1 at 0.2 A g−1 and maintained a high cycling stability with 98.7% retention after 1000 cycles at 10 A g−1. The incorporation of Cu2+ pillars and interlayer water improved the structural stability and Zn2+ diffusion, offering enhanced rate performance and long-term cycling stability. The study highlights the effective integration of computational and experimental methods to optimize cathode materials for high-performance AZIBs, providing a promising strategy for the development of stable and efficient energy storage systems.