Dispersed cobalt nanoparticles in the nitrogen doped carbon black as efficient catalysts for oxygen reduction reaction and Zinc-Air batteries

Abstract

Developing an effective and durable Pt-free oxygen reduction reaction (ORR) catalyst for Zinc-Air batteries (ZABs) is propitious to easing the energy and pollution crisis. Herein, we have prepared Co nanoparticles/N-doped carbon (Co/N/C) with tunable Co contents by the pyrolysis of polydopamine-coated cobalt phthalocyanine/carbon black precursors. Benefiting from the well-dispersed Co nanoparticles and the formation of various active sites (i.e. pyridinic, graphitic N and Co-Nx), the resulting Co/N/C-2.86 wt% catalysts possess a half-wave potential of 0.84 V and a mass activity of 5.18 A/g, illustrating the superior ORR performance. Noteworthy, the ZABs with the cathode of Co/N/C-2.86 wt% display an outstanding cell performance with a large open-circuit voltage (1.542 V), a high specific discharge capacity (744 mAh g−1) and an excellent maximum power density (236 mW cm−2). This work offers a promising approach to rationally design and fabricate high-performance ORR electrocatalysts for advanced ZABs.