Electron‐Polaron‐Enriched Fe‐Doped Co 3 O 4 Nanoneedle Arrays Enabled by Tip Curvature and Vacancy Engineering for Efficient Oxygen Evolution

ABSTRACT The oxygen evolution reaction (OER) is a key process in various renewable energy conversion systems, yet its sluggish kinetics severely limit overall efficiency. Herein, we co‐engineer polaron density and localization through morphology‐induced field concentration in V O ‐Fe‐Co 3 O 4 nanoneedles. Fe doping increases tip curvature, concentrating fields and charge, while oxygen vacancies donate carriers and promote small‐polaron formation. Tip‐localized polarons enrich mobile carriers, strengthen electronic coupling, and optimize * OH/ * O/ * OOH adsorption, lowering charge‐transfer resistance and accelerating proton‐coupled electron transfer. Consequently, the V O ‐Fe‐Co 3 O 4 achieves an overpotential of merely 240 mV at 10 mA cm −2 with an ultra‐low Tafel slope of 30.05 mV dec −1 , and > 300 h stability at 100 mA cm −2 in alkaline media. A zinc‐air battery based on V O ‐Fe‐Co 3 O 4 exhibits excellent stability for more than 400 cycles at a current density of 10 mA cm −2 . This work identifies directional polaron control as an effective route to high‐activity OER electrocatalysts.