Synergistic Pre-Intercalation and Architectural Tuning to Suppress Vanadium Dissolution for Enhanced Aqueous Zinc-Ion...

The inherent dissolution and stability issues of pristine vanadium (V) based cathodes limit their performance in rechargeable aqueous zinc-ion (Zn²⁺) batteries (RAZIBs). Herein, we report a morphology-controlled V-based hollow microsphere cathode (hRVO-G) conceived via guest pre-intercalation (Ru), architectural tuning, and rGO encapsulation strategy. The Ru pre-intercalation expands the interlayer spacing of the V host, promotes the Zn^{2 +} (de)intercalation, and induces the V─O─Ru interfacial bonding, which lowers the valence state of the V. The existence of reversible dynamic V─O─Ru bond and lower Zn diffusion barrier in hRVO-G, is further confirmed by theoretical studies. The hollow microsphere architecture mitigates volume changes and internal stress, ensuring structural stability during prolonged cycling. The rGO functionalization improves conductivity, suppresses the Ru-V oxide agglomeration, and explores the maximum active site. Consequently, hRVO-G delivers a high specific capacity of 399.8 mAh g^{- 1} at a current density of 0.1 A g^{- 1} (vs. 170.8 mAh g^-1 for pristine stacked V₂O₅) and achieves 73.1% capacity retention over 1000 cycles, with the charge storage dominated by the capacitive contributions. This work highlights the synergistic interfacial modulation through pre-intercalation and architectural tuning to address dissolution and stability concerns in the V-based cathodes for RAZIBs.