Carboxymethyl Cellulose‐Induced Phase Transformation of Metal‐Organic Framework‐Derived Vanadium Oxides for High‐Rate and High‐Capacity Zinc Storage

Conventional synthesis of metal oxides from metal‐organic frameworks (MOFs) precursors typically relies on high‐temperature pyrolysis, which inherits the structural advantages of MOFs but is energy‐intensive. Herein, we report a low‐energy hydrothermal transformation strategy to fabricate two phase‐pure vanadium oxides (VO 2 and V 3 O 7 ·H 2 O) without high temperature treatment. The tunnel‐structured VO 2 nanobelts with high oxygen vacancy defects can be obtained by the function of water‐soluble polymer sodium carboxymethyl cellulose (CMC), which plays a critical phase‐directing role by coordinating with released vanadium ions on the V‐MOF surface. As a cathode for aqueous zinc‐ion batteries (AZIBs), the VO 2 nanobelts deliver high specific capacities of 320.8 mAh g −1 at 0.1 g −1 and 242.2 mAh g −1 at 10 A g −1 , significantly outperforming the CMC‐free V 3 O 7 ·H 2 O counterpart (309.5 and 162.3 mAh g −1 ). Moreover, VO 2 exhibits a high‐capacity retention of 73.6% after 1400 cycles at 10 A g −1 . The enhanced electrochemical behavior arises from the synergistic effects of the tunnel structure, uniform nanobelt morphology, and abundant oxygen vacancies, which facilitate Zn 2+ diffusion and electronic conduction. This work not only provides a high‐performance VO 2 cathode for AZIBs but also establishes a general, low‐cost, and scalable hydrothermal route for phase‐engineered MOF‐derived metal oxides.