N, S dual-doped carbon aerogels-supported Co9S8 nanoparticles as efficient oxygen reduction reaction electrocatalyst for zinc-air battery

Abstract

The innovative design of highly active and noble-metal-free electrocatalysts for the oxygen reduction reaction (ORR) is urgently required for the widespread application of Zinc-air batteries (ZABs). This study presents a porous composite, Co9S8 @NSC, which integrates N and S co-doped carbon aerogels with Co9S8 nanoparticles to create ideal ORR electrocatalysts. The porous carbon aerogels posesess a high specific surface area, which offers abundant catalytic sites and efficient channels for the reactants and electrolytes, while maintaining a uniform distribution of nanoparticles during long-term operation. The collaboration of ORR-active Co9S8 nanoparticles and N and S co-doped carbon aerogels significantly improves ORR performance. Co9S8 @NSC demonstrates a competitive ORR activity, including a high half-wave potential (E1/2, 0.85 V), fast electron transfer kinetics (Tafel slop, 53.3 mV dec−1), and prominent long-term stability. When utilized as an air cathode catalyst in primary Zn-air batteries, the Co9S8 @NSC electrode displays a power density of 150.9 mW cm−2 and a specific capacity of 735 mAh gzn−1. Overall, this work presents a promising electrocatalyst design for ORR, which could greatly benefit the development of ZABs.