<p>Rechargeable aqueous zinc-ion batteries (AZIBs) are regarded as promising candidates for large-scale energy storage systems owing to their low cost, high inherent safety, and eco-friendliness. However, developing superior cathode materials with long cycle life and high capacity remains a key challenge for the practical application of AZIBs. Herein, we adopt a facile one-step hydrothermal strategy by regulating solution pH to synthesize high-performance three-dimensional (3D) hierarchical porous ammonium tetravanadate ((NH₄)₂V₄O₉) cathode material constructed from interlaced nanosheet clusters for AZIBs. The morphological evolution of (NH₄)₂V₄O₉ is driven by the solution pH (3.5, 4.5 and 5.5), where 1D nanorods are initially formed, followed by the self-assembly of 2D nanosheets into 3D clusters and finally the random aggregation of nanosheets with uneven dispersion. At an optimal pH of 4.5, the as-prepared hierarchical porous (NH₄)₂V₄O₉ nanosheet clusters feature a large specific surface area of 35.4 m² g^− 1, which effectively mitigates volume expansion/contraction, provides abundant Zn²⁺ storage sites, and shortens ion diffusion pathways. Electrochemical tests demonstrate that the (NH₄)₂V₄O₉ nanosheet clusters exhibits an ultrahigh discharge capacity of 448.7 mAh g^− 1 at 0.1&#xa0;A g^− 1, along with excellent cycling stability—retaining 97.4% capacity after 100 cycles at 0.5&#xa0;A g^− 1 and 90.1% capacity over 8000 cycles at an ultrahigh current density of 15&#xa0;A g^− 1, benefiting from the capacitive-dominated reaction kinetics, good reversibility of Zn²⁺ (de)intercalation, as well as fast charge transfer and Zn²⁺ diffusion ability. This work provides a feasible pH-dependent morphological design strategy for fabricating high-capacity and long-lifespan (NH₄)₂V₄O₉ cathodes for AZIBs.</p>