Activating H₃O⁺ Intercalation Chemistry in Aqueous Zn-VO₂(B) Batteries via Tungsten Doping and Oxygen Vacancies

Vanadium-based materials have shone brightly in aqueous Zn metal batteries due to their high theoretical capacity and excellent high-rate capability. However, the severe vanadium dissolution attacked by H⁺ during cycling has persistently resulted in unsatisfactory cycling stability at low current density (generally ≤0.5 A g^-1). To address this critical issue, a reversible H₃O⁺ intercalation chemistry in tunnel-structured VO₂(B) materials is herein reported, which is activated by disordered substitution doping of V⁴⁺ by W^5+/6+ ions while simultaneously introducing oxygen vacancies. Both experiments and theoretical calculations demonstrate that H₃O⁺ exhibits stronger adsorption energy on the (110) plane of synthesized W_0.05V_0.95O_1.94(B) electrode than H⁺. Moreover, the synergy between W^5+/6+ dopants and oxygen vacancies can effectively improve the distribution of adsorption sites for H₃O⁺, contributing to an enhanced utilization of surface-active sites. As a result, this cathode chemistry delivers a high specific capacity of 407 mAh g^-1 at 0.1 A g^-1 and maintains 357 mAh g^-1 with almost no capacity decay after 100 cycles at 0.5 A g^-1. These findings offer a promising pathway for developing rechargeable long-life vanadium-based cathodes.