Ultrafast Preparation of Defective Nitrogen-Doped Carbon by Carbon Thermal Shock Method with Efficient Oxygen Reduction Reaction Activity for Zn-Air Battery

Abstract

Developing effective strategies to improve the electrocatalytic activity of carbon-based materials is significant for Zn-air batteries (ZABs). Herein, nitrogen-doped carbon with abundant sp3-hybridized carbon defects (NC-CTS) were synthesized through a nonthermodynamic equilibrium carbonization process called carbon thermal shock (CTS). The NC-CTS catalyst exhibited a superior oxygen reduction reaction (ORR) activity with a half-wave potential of 0.81 V vs RHE and good stability in alkaline electrolyte, exceeding the NC-Furnace catalyst, which was fabricated by a thermodynamic equilibrium process. The better ORR performance originated from the increased density of sp3-hybridized carbon defects as the active sites and the optimized adsorption energy of intermediate species. The sp3-hybridized carbon defects were attributed to the obstruction of atom mobility and aggregation due to the ultrashort duration time of CTS. Furthermore, the ZABs using NC-CTS catalysts as the cathode showed good discharge performance and high cycling stability with a power density of 110 mW cm–2. This study demonstrated an effective strategy to modulate the ratio of sp3/sp2 of carbon-based electrocatalysts for the development of advanced carbon-based electrocatalysts to enhance the ORR performance and for the development of ZABs.