In Situ Synthesized Cobalt Nanocrystal via Bipyridine Ligand Cobaltic Borate Annealing Method for High‐performance Zinc‐air Battery

Abstract A “butterfly‐like” metal templated borate, [Co 2 (bpy) 4 (C 2 O 4 )]·[B 5 O 6 (OH) 4 ] 2 ·py 2 (1, bpy = 2,2′‐bipyridine, py = pyridine), was synthesized via a solvothermal method. For the first time, the coordination of Co 2+ ions with (C 2 O 4 ) 2− ions in borate systems was observed. Notably, upon pyrolyzing precursor compound 1 , high‐resolution transmission electron microscopy (HRTEM) revealed a catalyst with a carbon‐supported Co nanocrystal structure, which significantly enhanced the oxygen reduction reaction (ORR) performance, achieving a half‐wave potential comparable to that of Pt/C. More importantly, the catalyst outperformed Pt/C when applied in a zinc‐air battery.