A graphite/amorphous diamond coupled framework with high ORR and OER performance applied as a cathode catalyst in zinc–air batteries

Abstract

With the consumption of fossil energy, the energy crisis is becoming more and more serious. Chitosan, as a green energy source, can solve this problem. In this paper, renewable chitosan is used as a carbon and nitrogen source and boric acid as a B source. A B,N co-doped graphite/amorphous diamond coupling framework was designed to increase the amount of sp³ carbon inside the material, construct the sp²/sp³ carbon interface and use the unique electron deficient properties of B atoms to adsorb more OH*, O*, OOH* and O₂. The test result in 0.1 M KOH solution shows that mesoporous carbon has an initial potential of 0.924 V, a half-wave potential of 0.821 V and a limiting current density of 5.26 mA cm⁻². At the same time, the corresponding overpotential is 285 mV at 10 mA cm⁻² and the bifunctional potential (ΔE = E_j=10 − E_1/2) of mesoporous carbon is 0.694 V. Zinc–air battery test results show that the maximum peak density is 116.2 mW cm⁻² at 170 mA cm⁻² and that it also has a specific capacity of 812 mA h g_Zn⁻¹ at 10 mA cm⁻². This showed that the catalyst has good ORR and OER properties and a good prospect in practical application.