Carbon Nanotube-Encapsulated Cobalt for High-Efficiency Zinc-Air Flow Battery: Integration of Single Atom Catalysis and Space Confinement

Abstract

Abstract To meet the practical demand of zinc-air battery cathode noble metal catalyst substitutes are required. Herein, we integrating non-precious single-atom catalysis and space confinement present an effective approach for the large-scale, in-situ growth of CoN3-doped carbon nanotubes (CNTs) coated with Co nanoparticles (Co@CoN3/CNTs), without adding additional additives. The in-situ grown CNTs serves a dual purpose by acting as a matrix for dispersed atomic CoN3 sites and providing a space confinement effect on Co nanoparticles, resulting in lower energy barriers and superior mass transport capability. Furthermore, Co3C species derived from the Co-based zeolitic imidazolate frameworks (Co-ZIFs) act as catalysts for the direct arrangement of surrounding C-N groups. The resulting Co@CoN3/CNTs-800 displays remarkable oxygen reduction reaction (ORR) performance, with a half-wave potential of 0.84 V surpassing that of Pt/C counterparts. Moreover, the rechargeable zinc-air flow battery exhibits a peak power density of 169.5 mW cm-2 and superior recyclability.