Crystalline‐Amorphous Phase and Oxygen Vacancies Synergistically Regulate Vanadium Electronic States for Unleashing Zinc‐Ion Storage Performance
Jingyu Sun, Li Zhang, Fengbo Li, Fajun Yang, Meiyu Liu, Shaobin Li, Deqing Zhang
Abstract
Abstract Zinc‐ion capacitors (ZICs) are emerging as a compelling choice for energy storage in future, promising high power and energy densities coupled with eco‐friendly characteristics. This work presents a novel approach to enhance the performance of ZICs by employing a one‐step solvothermal synthesis to growth V‐MOF on the surface of V 2 CT X ‐MXene, followed by annealing to fabricate a 3D cross‐linked VO X /V 2 CT X ‐MXene‐x(VO X /MXene‐x) composite. The unique structure demonstrates excellent conductivity and high redox reaction activity, which significantly shortens the Zn 2+ diffusion path. Moreover, the intertwined crystalline‐amorphous structure efficiently suppresses lattice volume expansion during Zn 2+ (de)intercalation. Density functional theory (DFT) reveals that the amorphous V 2 O 5 enhances conductivity, lowers the Zn 2+ capture energy barrier, and improves charge transfer efficiency. The introduction of oxygen vacancies further enhances the electronic transport. The VO X /MXene‐4 composite exhibits a specific capacity of 336.39 mAh g −1 at 1 A g −1 , maintaining 213.06 mAh g −1 at 10 A g −1 , indicating outstanding rate performance, along with an energy density of 356.27 Wh kg −1 and a power density of 1280 W kg −1 . This work offers novel insights for the design of electrode materials that feature intertwined crystalline‐amorphous phases, providing valuable insights into ion transport mechanisms and strategies to enhance Zn 2+ diffusion kinetics.