Atomically thin vanadium oxide nanosheets via top-down exfoliation for ultrafast-charging zinc-ion batteries

Aqueous zinc-ion batteries (ZIBs) are a promising energy storage solution due to their high safety, environmental friendliness and low cost. Although the high ionic conductivity of aqueous electrolytes and fast kinetics of zinc plating/stripping hold promise for fast discharge/charge processes, the rate capability of AZIBs remains limited due to poor ion and electron transport in cathode materials. This study addresses this challenge by developing atomically thin vanadium oxide nanosheets (∼2 nm thickness) through a top-down exfoliation strategy using bulk ZnV₆O₁₆·nH₂O. Driven by small-molecule-assisted interlayer interactions, a mild wet ball-milling and ultrasonication process effectively disrupts interlayer hydrogen bonding and enables efficient layer separation. Benefiting from the reduced thickness (layers) and weakened interlayer interactions, the exfoliated ZnV₆O₁₆·nH₂O nanosheets deliver a solid-state ion diffusion coefficient nearly eight times higher than the bulk, together with a decreased diffusion barrier (84.6 meV versus 187.5 meV), promoting rapid charge storage. Finally, a high capacity of 346 mAh g^-1 (4.5 times that of the bulk) at 50 A g^-1 and excellent cycling stability (77% capacity retention after 30 000 cycles at 100 A g^-1) are achieved in coin-type cells based on ultrathin ZVO nanosheets. Moreover, a 45 cm² pouch cell maintains 98% capacity retention over 550 cycles, highlighting the strong potential for scalable preparation and practical application. These findings demonstrate a promising strategy for designing high-performance, fast-charging batteries, advancing grid-scale energy storage solutions.