Triazine organic framework derived Fe single-atom bifunctional electrocatalyst for high performance zinc air batteries

Owing to their adjustable local structure and coordination environment, Fe single-metal site electrocatalysts become superior alternatives to the precious metal-based systems for oxygen reduction reactions (ORR) and oxygen evolution reactions (OER). However, they often suffer from complicated preparation methods. The optimized conditions hide in a narrow window and require a large amount of screening work. Moreover, the porous support may collapse during high temperature, resulting in dead volume and low atomic usage efficiency. Herein we report a facile build-up of atomically dispersed Fe single metal site (Fe–N–C) derived from Fe-doped thermalized covalent triazine frameworks (TTF) towards bifunctional ORR/OER catalysts. The TTF-derived carbon provides a platform for the formation and uniform dispersion of single-atom Fe–N catalytic centers. A high electrocatalytic behavior towards ORR (E1/2 = 0.891 V) and OER (Ej = 10 = 1.543 V) in alkaline medium is achieved with excellent stability and anti-methanol poisoning activity. Impressively, its metal mass activity is 62 times higher than commercial 20 wt% Pt/C. The Zn-air battery (ZAB) based on the catalyst achieves a high capacity of 783.2 mAh g−1, a low voltage gap of 0.55 V and an outstanding rechargeability of 1650 cycles (∼550 h), placing it as one of the best-performing ZABs.