Self‐Adaptive Proton Intercalation‐Enabled High Capacity and Cycling Stability of Vanadium Oxide Cathodes in Aqueous Zn‐Ion Batteries

Abstract Intercalation of metal ions and organic molecules into vanadium‐based cathodes is recognized as an effective strategy to enhance the performance of zinc‐ion batteries. However, in many studies, the role of intercalated organic molecules has been oversimplified and attributed to structural modulation or improved Zn 2+ transfer. The electrochemical characteristics of the organic molecules themselves are not sufficiently investigated. Herein, acetone (AC) molecules are employed as probes and co‐intercalated with Mn 2+ into layered V 2 O 5 ·nH 2 O to investigate their respective functions. Mn 2+ form strong coordinative interactions, reinforcing the structural integrity of framework. Meanwhile, the polar groups of AC act as redox‐active sites for H + intercalation. This balanced coordination environment enables a dynamic structural evolution during extended cycling, which self‐adaptively enhances the contribution of H + rather than Zn 2+ . This self‐adaptive H + intercalation allows the material to simultaneously maintain structural robustness and improve charge storage performance. Consequently, this cathode achieves a high specific capacity of 409 mAh g −1 at 0.1 A g −1 , and under 5 A g −1 it increases to 379 mAh g −1 after 3000 cycles before settling at 279 mAh g −1 (126.8% retention) after 7400 cycles.