Engineering hollow structured bimetal incorporated carbon towards oxygen reduction/evolution reaction for zinc-air battery

Oxygen electrode is the key component that hinders the performance of zinc-air battery. In this work, hollow structured bimetal incorporated carbon catalyst is designed by incorporating bimetallic Fe/Co in polystyrene microspheres with different functional groups. The results reveal that the Fe/Co-N@NCs synthesized using polystyrene microspheres with amide groups shows the best electrochemical activity. The prepared Fe/Co-N@NCs delivers an onset potential of 0.90 V and half-wave potential of 0.82 V for oxygen reduction reaction. Also, Fe/Co-N@NCs shows oxygen evolution potential of 1.66 V at 10 mA cm −2 . Moreover, the oxygen electrode activity based on Fe/Co-N@NCs is 0.85 V, demonstrating a good bifunctional performance. A voltage and capacity of 1.43 V and 807 mAh·g −1 are obtained based on the battery using Fe/Co-N@NCs, outperforming that using Pt/C + RuO 2 (1.40 V and 803 mAh·g −1 ). Furthermore, a power density of 81 mW cm −2 is realized using the battery with Fe/Co-N@NCs, higher that with Pt/C + RuO 2 (79 mW cm −2 ). In all, this work provide an alternative pathway for designing hollow structured bimetal incorporated carbon as electrocatalysts in zinc-air battery. • Hollow structured bimetal doped carbon as oxygen reduction/evolution catalyst. • High catalytic activity of Fe/Co-N@NCs for oxygen reduction/evolution reaction. • Mechanism of oxygen reduction/evolution based on density functional theory. • Better zinc-air battery performance using Fe/Co-N@NCs, compared to Pt/C + RuO 2 . • Long-term stability of Fe/Co-N@NCs as a cathode in zinc-air batteries.