"Dual- Engineering" Strategy to Regulate NH4V4O10 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 NH4V4O10 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.