Fe, Zn Co-Doped Porous Carbon Nanofiber-Based Rechargeable Zinc Air Batteries with Stable Operation over 1600 h

Rational design of effective non-noble metal-based electrocatalysts with high conductivity, abundant active sites, and superior stability for zinc–air batteries (ZABs) with long-term cycling ability is highly demanded. A suitable carrier that can provide a high specific surface and porous structure to facilitate the exposure of active sites and the diffusion of reactants, products, and charges is of great importance. Herein, one-dimensional (1D) Fe–Zn-doped porous carbon fibers (Fe–Zn@NCF) are prepared from a polymer fiber matrix encapsulated with Fe-doped ZIF-8 nanocrystals by pyrolysis. The Fe–Zn@NCF exhibits good performance toward the oxygen reduction reaction or oxygen evolution reaction. Impressively, the assembled ZAB with Fe–Zn@NCF as the catalyst delivers a maximum peak power density of 184.6 mW cm–2, excellent rechargeability with a round-trip efficiency of 66.5%, and stable operation over 1600 h (800 cycles). These excellent electrocatalytic performances can be attributed to the Fe/Zn-based dual catalytic active sites and the 1D carbon fiber support of the catalyst with a hierarchical porous structure, a large surface area, and high conductivity that can facilitate fast mass and electron transportation and maintain the structural stability of the catalyst during cycling.