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.

Automated summary

This study aims to develop non-noble metal-based electrocatalysts for zinc-air batteries with long-term cycling ability. Fe-Zn-doped porous carbon fibers (Fe-Zn@NCF) are synthesized and found to have excellent performance in oxygen reduction and oxygen evolution reactions. The assembled ZAB with Fe-Zn@NCF as the catalyst demonstrates outstanding electrochemical performance with high power density, good rechargeability, and stable operation over a long period. These excellent performances can be attributed to the active sites and hierarchical porous structure of the Fe-Zn@NCF catalyst.