Vanadium Cation Exchange‐Driven Reconstruction of MOF‐Derived Cobalt Hydroxide Electrodes for Electrocatalysis and Energy Storage

ABSTRACT The development of earth‐abundant oxygen evolution reaction (OER) electrocatalysts remains challenging because structural reconstruction and electronic/defect modulation are often addressed separately. Herein, a room‐temperature vanadium cation exchange strategy that enables structural reconstruction and electronic/defect modulation is reported. Vanadium cation exchange removes organic ligands and drives the phase transformation to mesoporous cobalt hydroxide using ZIF‐67 grown on nickel foam, while high‐valence vanadium incorporation increases the cobalt oxidation state and promotes oxygen vacancy formation. The optimized V _20– Co(OH) ₂ electrode exhibits current densities of 50 mA cm ⁻² and 100 mA cm ⁻² at overpotentials of 268 and 293 mV, respectively, in 1.0 M KOH, and maintains stable operation for 150 h. In situ Raman and post‐stability analyses reveal the formation of a CoOOH‐like active surface during OER operation, while oxygen vacancy‐related features and a high cobalt oxidation state are largely retained after operation. Spectroscopic, electrochemical, and kinetic analyses reveal an increased contribution from lattice oxygen participation during OER. The defect‐engineered electrode exhibits enhanced performance in supercapacitors and zinc–air batteries, demonstrating a generalizable electrode engineering strategy for energy storage and conversion systems.