Double-Activator Modulation of Ultrahigh Surface Areas on Doped Carbon Catalysts Boosts the Primary Zn-Air Battery Performance

Abstract

The exploration of high-performance and low-cost carbon-based catalysts as an excellent substitute for Pt-based catalysts for the oxygen reduction reaction (ORR) is key to solve the commercialization of metal-air batteries. Herein, we report an efficient strategy to design a porous-rich N, F-codoped carbon-based ORR catalyst (A-NFCF-950) by double-activator (ZnCl2, NH4F) modulation of the specific surface area and pore structure. Among them, ZnCl2 as a pore modifier can help to produce an ultrahigh specific surface area (up to 2251 m2 g-1) and also facilitate the exposure of more doping active sites. Furthermore, the NH4F modifier can be convenient for the charge density regulation of adjoining carbon atoms, which further significantly promotes the graphitization degree and accelerates oxygen dissociation at the catalyst. The electrochemical results indicate that the ORR activity and cycling stability of A-NFCF-950 are comparable to those of the Pt/C catalyst in a 0.1 M KOH electrolyte. In addition, the assembled Zn-air battery using A-NFCF-950 shows a higher power density (220 mW cm-2) and a larger capacity energy density (872 Wh kg-1 Zn). This work opens a way to synthesize doped carbon materials with ultrahigh surface areas serving for conventional Pt-based materials toward the ORR in metal-air batteries.