Novel aluminum vanadate as a cathode material for high-performance aqueous zinc-ion batteries

Rechargeable aqueous zinc-ion batteries (AZIBs) have garnered widespread attention as a new large-scale energy storage candidate owing to their low cost and high theoretical capacity. Because of the unique divalent state of Zn²⁺and the existence of a strong electrostatic repulsion phenomenon, researchers are currently focusing on how to prepare high-performance cathode materials. In this study, we synthesized aluminum vanadate (AlV₃O₉) as a cathode material for AZIBs using a solvothermal method. Al³⁺acted as a pillar in the resultant structure and stabilized it. Furthermore, this large interlayer spacing enhanced the ion diffusion coefficient and accelerated the ion transport process. Because of these advantages, the AlV₃O₉(AVO) cathode exhibited excellent electrochemical performance, including a high capacity of 421.0 mA h g^-1at 0.1 A g^-1and a stable rate capability of 348.2 mA h g^-1at 1 A g^-1. Moreover, it exhibited a specific capacity of 202 mA h g^-1even at a high current density of 3 A g^-1(the capacity retention rate reached 84.38% after 1600 cycles). The prepared ZIBs presented a high power density of 366.6 W kg^-1at an energy density of 286 W h kg^-1. These extraordinary results indicate the great application potential of AVO as a cathode material for AZIBs.