Heteroatom-doped carbon sheets as metal-free electrocatalysts for promoting the oxygen reduction reaction in Zn-air batteries.

Zn-air batteries are promising energy devices for future sustainable development. It is crucial to promote the cathodic reaction, oxygen reduction reaction (ORR), by applying active electrocatalysts. Herein, a metal-free ORR electrocatalyst has been fabricated by doping S and N atoms into carbon sheets (S-N-C), and it displays high ORR activity and outstanding performance in Zn-air batteries. The S-N-C electrocatalyst exhibits remarkable ORR activity with a half-wave potential of 0.89 V, which is far exceeding that of the commercial Pt/C benchmark and most reported carbon-based electrocatalysts. A full-cell Zn-air battery device with S-N-C as a cathode catalyst is demonstrated, which delivers high power density and good durability.