Local Electric Field‐Driven Reaction Pathway Regulation via Ru Single Atoms on Highly Curved Carbon Sphere for Stable Li–O ₂ Batteries

Single-atom catalysts (SACs) are extensively employed in Li-O₂ batteries owing to their exceptional atomic utilization efficiency and precise active-site control, which collectively enhance battery performance. However, weak metal-support interactions impede effective anchoring and electronic state modulation, leading to suboptimal catalytic activity, selectivity, and stability. Herein, we report a Ru single-atom/onion-like carbon sphere (Ru SACs/OCS) catalyst designed to accelerate oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) kinetics. This enhancement stems from the interplay of the local electric field induced by the tip effect, facilitating rapid mass transport of reactive species. Density functional theory (DFT) calculations and experimental results demonstrate that precise modulation of substrate nanostructure curvature significantly amplifies the local electric field intensity surrounding SACs on the support surface. This augmentation elevates surface charge density and active-site concentration of the catalyst, thereby promoting the preferential disproportionation of reaction intermediates at the catalyst surface. The proposed strategy offers a streamlined and effective approach to engineer SACs with highly curved heterostructures, enabling enhanced catalytic reactions in metal-air battery technologies.