Graphical AbstractVerifiedPrecision design of asymmetric cobalt single-atom catalysts for high-performance zinc-air batteries
The commercial viability of zinc-air batteries (ZABs) is constrained by the sluggish kinetics of the oxygen reduction reaction (ORR), which necessitates robust, cost-effective catalysts. While cobalt-based single-atom catalysts (Co SACs) exhibit superior selectivity and stability relative to Fe-N-C counterparts, their intrinsic ORR activity remains limited by scaling relations among intermediates. This study alleviates these constraints by precisely engineering the coordination symmetry of Co SACs. Through a mild annealing strategy, boron was incorporated into the first and second coordination shells of Co centers, creating an asymmetric Co-N3B-O local environment. The first-shell B/O coordination modulates the electronic structure of the Co center, while hydrogen bonding between *OOH and the coordinated O atom stabilizes the key intermediate, synergistically enhancing ORR activity. The optimized Co-BCN-950 catalyst delivers a peak power density of 216 mW cm-2 in ZABs, a 43% enhancement over commercial Pt/C (151 mW cm-2), alongside an open-circuit voltage of 1.43 V and a specific capacity of 790 mAh g-1. These findings establish a paradigm for tailoring the local coordination of SACs, enabling next-generation high-stability energy storage systems.
