Achieving Near‐Zero‐Strain via Volumetric Neutralization in an H 2 V 3 O 8 /MXene/VO 2 Cathode for Durable Zinc‐Ion Batteries

ABSTRACT Aqueous zinc‐ion batteries have gained broad attention in electrochemical energy storage due to their intrinsic safety and low cost. However, significant volume changes during Zn 2+ insertion/extraction remain a major barrier to limiting its application. Inspired by near‐zero thermal expansion achieved by combining materials with opposite expansion coefficients, we integrate two materials exhibiting opposite volume changes during cycling to realize a volumetric neutralization effect within the battery system. In situ X‐ray diffraction confirms the stable volumetric behavior of the H 2 V 3 O 8 /Ti 3 C 2 T x MXene/VO 2 composite. The composite electrode delivers strong electrochemical performance, including a discharge specific capacity of 457 mAh g −1 at 0.1 A g −1 , fast charge/discharge capability with a maximum capacity of 428 mAh g −1 at 10 A g −1 , and long‐term stability with 352 mAh g −1 retained after 5000 cycles at 10 A g −1 . Crucially, real‐time strain monitoring via an embedded fiber optic sensor directly records a near‐zero macroscopic volume change during cycling, validating the effectiveness of the synergistic neutralization design. These results demonstrate that the volumetric neutralization strategy is a powerful material design principle for mitigating structural degradation. This work provides a new pathway for developing high‐performance, structurally robust cathodes for durable aqueous zinc‐ion batteries.