"Dual- Engineering" Strategy to Regulate NH₄ V₄ O₁₀ as Cathodes for High-Performance Aqueous Zinc Ion Batteries

Aqueous zinc ion batteries (AZIBs) have attracted attention as a promising candidate for secondary battery energy storage due to their safety and environmental benefits. However, the vanadium-based cathode material NH₄ V₄ O₁₀ has the problem of structural instability. In this paper, it is found by density functional theory calculation that excessive NH₄ ⁺ located in the interlayer will repel the Zn²⁺ during the process of Zn²⁺ insertion. This results in the distortion of the layered structure, further affects the diffusion of Zn²⁺ and reduces the reaction kinetics. Therefore, part of the NH₄ ⁺ is removed by heat treatment. In addition, the introduction of Al³⁺ into the material by hydrothermal method is able to further enhance its zinc storage properties. This dual-engineering strategy shows excellent electrochemical performance (578.2 mAh g^-1 at 0.2 A g^-1 ). This study provides valuable insights for the development of high performance AZIBs cathode materials.