<p>Ammonium vanadate, possessing large capacity, excellent rate capability, and lightweight, stands out as a potential cathode material for aqueous zinc-ion batteries (AZIBs). Nevertheless, regulating the ammonium vanadate needed for synthesis remains a difficulty. In this paper, diverse kinds of ammonium vanadate were successfully fabricated by modifying the hydrothermal reaction time. With the prolongation of time, the morphology and crystalline phase of the products transformed from dendrite to rod-like and then to lamellar. The interlayer spacing of the material is increased from 9.81 to 10.57&#xa0;Å, thereby markedly diminishing the diffusion barrier for Zn²⁺. This structural optimization facilitates the acceleration of ion migration and enhances the rate of redox reactions. NVO-2 exhibits an exceptional specific capacity of 517 mAh g⁻¹ at 0.1 A g⁻¹, and a remarkable capacity retention of 96.8% after enduring 2000 cycles at 5 A g⁻¹. NVO-2 possesses a stable open-skeleton layered structure, a considerable (001) plane spacing, and a distinctive rod-like structure, which promote its highly reversible Zn²⁺ storage behavior. This research introduces an innovative approach to strategically developing superior cathode materials for AZIBs.</p> Graphical Abstract <p>Optimized hydrothermal synthesis yields NVO-2 with improved (001) spacing and rod-like shape, enhancing Zn²⁺ storage.</p> <p></p>