Easy Preparation of N-Doped Graphene-like Nanosheets as Excellent Metal-Free Cathodic Electrocatalysts of Zn-Air Battery

Carbon-based materials have been paid much attention due to their own good electroactivity and resources availability. Herein, we reported a simple and versatile synthesis strategy for the preparation of nitrogen-doped and metal-free carbon catalysts with excellent oxygen reduction reaction (ORR) electroactivity. Using dicyandiamide (DCD) as nitrogen source and sucrose, beta-cyclodextrin and chitosan as different carbon sources, N-doped graphene-like nanosheet samples CN-nanosh(suc), CN-nanosh(cyc) and CN-nanosh(ch) were prepared by an easy pyrolysis of their mixture. The samples exhibited outstanding ORR electroactivity in alkaline media with a comparable performance to the benchmark Pt/C. Alkaline Zn-air battery with the prepared sample CN-nanosh(suc) as the cathodic catalyst displayed the maximum power density of 201.33 mW.cm(-2), and its discharge time can last for more than 50 h at a constant current density of 100 mW.cm(-2), which is close to the optimum values of the similar Zn-air battery with the metal-free cathodic electrocatalysts reported so far.