COF-derived Co nanoparticles@N-doped carbon electrocatalysts for high performance Zn-air batteries

Precise modulation of the structure and composition of electrocatalysts is critical for promoting the kinetically sluggish process of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Covalent organic frameworks (COF) offer a novel way to create highly efficient electrocatalysts due to their tunable composition, structure and surface area. Herein, we report a high-efficiency bifunctional electrocatalyst comprising Co nanoparticles embedded within N-doped carbons (Co@NCs) for Zn-air batteries (ZABs). The Co@NC is yielded via the coordination of a triazine COF with Co-containing precursors and subsequent calcination under inert atmosphere. The as-prepared Co@NC exhibits remarkable ORR/OER performance and great potential in rechargeable ZABs. The liquid ZAB constructed with Co@NC provides both high specific capacity and power density. Remarkably, the ZAB exhibits a voltage gap of 0.8 V during discharge and charge cycles and high stability for 220 h compared to the Pt/C-assembled battery. This strategy for regulating electrocatalytic activities of COF-derived carbon materials could be expanded for creating various carbon catalysts.