Empirical Confirmation of Theoretical Predictions for Amorphous H/VO₄ Cathodes: Advancing Durability and Efficiency in Zinc‐Ion Batteries

Advancing cathode materials is crucial for the broader application of aqueous zinc-ion batteries (ZIBs) in energy storage systems. This study presents amorphous H/VO₄ (HVO), a novel cathode material engineered by substituting H⁺ for Mg²⁺ in Mg₂VO₄ (MgVO), designed to enhance performance of ZIBs. Initial exploration of MgVO through ab initio molecular dynamics (AIMD) simulations and density functional theory (DFT) calculations revealed a favorable Mg²⁺ and Zn²⁺ exchange mechanism. This mechanism notably reduces electrostatic interactions and facilitates ion diffusion within the host lattice. Building upon these findings, in this work, theoretical calculations analysis indicated that amorphous HVO offers a higher diffusion coefficient for Zn²⁺ ions and fewer electrostatic interactions compared to its crystalline MgVO precursor. Subsequent empirical validation is achieved by synthesizing amorphous HVO using a rapid ion-exchange process, effectively replacing Mg²⁺ with H⁺ ions. The synthesized amorphous HVO demonstrated 100% capacity retention after 18000 cycles at a current density of 2 A g^-1 and exhibited exceptional rate performance. These findings underscore the significant potential of HVO cathodes to enhance the durability and efficiency of aqueous ZIBs, positioning them as promising candidates for future energy storage technologies.