Activating H ₃ O ⁺ Intercalation Chemistry in Aqueous Zn‐VO ₂ (B) Batteries via Tungsten Doping and Oxygen Vacancies

Abstract 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 H ₃ O ⁺ intercalation chemistry in tunnel‐structured VO ₂ (B) materials is herein reported, which is activated by disordered substitution doping of V ⁴⁺ by W ^5+/6+ ions while simultaneously introducing oxygen vacancies. Both experiments and theoretical calculations demonstrate that H ₃ O ⁺ exhibits stronger adsorption energy on the (110) plane of synthesized W _0.05 V _0.95 O _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 H ₃ O ⁺ , 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.