Novel coal-based carbon encapsulating Co-N-C derived from ZIF-67 composite as an efficient chainmail electrocatalyst for zinc-air batteries.

Energy shortages and the global climate crisis have led researchers to develop renewable clean energy sources. Zinc-air batteries have attracted much attention due to their high theoretical energy density, safety, and conversion efficiency. However, the cathodic oxygen reduction reaction (ORR) exhibits slow reaction kinetics and high reaction energy barriers, which require catalysts with high activity, selectivity, and stability to improve the reaction rate. Chainmail catalysts have attracted attention in the field of energy conversion and storage due to their structural stability. In this paper, coal-based carbon encapsulating Co-N-C chainmail electrocatalysts are designed and constructed, which can effectively reduce the thermal crumpling phenomenon of the framework structure, enhance the defect content and provide active sites for ORR. The results show that G/Co-N-C-0.025 exhibits a higher half-wave potential than that of Pt/C, with a high ultimate current density of 4.6 mA cm−2, good cycling stability, and high methanol resistance. A primary zinc-air battery is assembled, with an open-circuit voltage of 1.417 V and a maximum power density of 82 mW cm−2. The specific capacity is 789.2 mAh g−1 at a current of 20 mA cm−2. This work provides new ideas for the design and application of high-performance chainmail electrocatalysts. [Display omitted] • Coal-based carbon encapsulating Co-N-C chainmail electrocatalysts are designed. • It exhibits the excellent catalytic activity for 4e oxygen reduction reactions. • The performance of assembled zinc-air battery is comparable to that of Pt/C. [ABSTRACT FROM AUTHOR]