Core–Shell Co@v‐CoO x /C Electrocatalysts With Balanced Intermediate Adsorption for High‐Performance Rechargeable Zinc–Air Batteries

Vacancy engineering offers an effective route to tailoring Co‐based oxygen electrocatalysts, yet vacancy‐rich sites can also intensify oxygen‐intermediate binding and impede active‐site regeneration if their polarized coordination environments are not properly regulated. Herein, a metal‐core‐buffered vacancy‐shell strategy is proposed by coupling ultrasmall metallic Co nanodots with a Co‐vacancy‐rich CoO x /C shell within a conductive mesoporous carbon framework. The metallic Co core serves as a nanoscale electron reservoir, while the vacancy‐rich CoO x /C shell provides adsorption‐regulating Co─O─C motifs for oxygen intermediates. Structural and spectroscopic characterizations confirm the formation of a carbon‐confined Co/CoO x core–shell architecture with abundant vacancy‐related defects. In situ Raman spectroscopy and density functional theory calculations reveal that interfacial electronic coupling buffers the vacancy‐induced polarized Co─O─C motifs, downshifts the Co 3d‐band center, and weakens excessive *OH binding, thereby balancing oxygen‐species activation with active‐site regeneration. As a result, Co@v‐CoO x /C delivers a high ORR half‐wave potential of 0.871 V, an OER overpotential of 319 mV at 10 mA cm −2 , and a small bifunctional potential gap of 0.678 V. Rechargeable Zn‐air batteries based on Co@v‐CoO x /C achieve a peak power density of 184 mW cm −2 and stable cycling for approximately 3200 h, while flexible devices also show high power output and mechanical tolerance.