Boosting BifunctionalElectrocatalysis via SynergisticTip and Vacancy Engineering for Advanced Zinc-Air Batteries

Abstract The development of catalysts capable of synergistically accelerating redox and mass transport kinetics is essential for high-performance zinc-air batteries (ZABs) yet remains a formidable challenge. Herein, we pioneer for the first time the integration of ultrahigh curvature and atomic defects into a needlelike Co3O4 electrocatalyst (needle VO-Co3O4), enabling the construction of a reactant-enriched and transport-favorable interfacial microenvironment in ZABs. The high-curvature needlelike morphology induces pronounced tip effects, which generate intensified local electric fields that enrich OH– ion species and promote rapid gas-bubble detachment at the tips, thereby minimizing active-site blockage and sustaining high-rate operation. Moreover, the introduced oxygen vacancies effectively tailor the electronic structure of Co centers, optimizing the adsorption of oxygenated intermediates and reducing the reaction energy barrier, which collectively boosts the intrinsic catalytic activity. Benefiting from this advantage, the needle VO-Co3O4 exhibits outstanding bifunctional performance with a low redox overpotential gap (ΔE) of 0.824 V. When implemented as a cathode catalyst in ZABs, it delivers a high specific capacity of 869.1 mAh gZn–1 and a peak power density of 172.8 mW cm–2. This work unveils the coupled effects of curvature-induced field enhancement and vacancy engineering in tailoring interfacial reaction environments, offering a generalizable strategy for designing next-generation electrocatalysts.