Self-standing electrospun Co/Zn@N-doped carbon nanofiber electrode for highly stable liquid and solid-state rechargeable zinc-air batteries and performance evaluated by scanning electrochemical microscopy at various temperatures

Zinc-air batteries (ZABs) as promising energy storage technologies have shown immense advantages of high energy density, abundant zinc reserves, low cost, and high safety. However, the sluggish oxygen reduction reaction (ORR) kinetics at the cathode still limits their overall performances. Herein, we fabricated a self-supported N-doped Co/Zn-carbon nanofiber membrane (Co/Zn@NCF) with superior activity and durability for the ORR. The liquid ZABs based on Co/Zn@NCF catalysts exhibited a cycling life of over 666 h with a charge/discharge voltage difference of 0.64 V and a voltage efficiency of 66 %. The fabricated flexible solid-state ZAB enables it to be stably charged and discharged under different bending angles. Strikingly the temperature-controlled scanning electrochemical microscopy (SECM) was developed to probe the local activity and selectivity of membrane-like Co/Zn@NCF at a submicrometer scale. This study provides an effective way for the development of self-supported catalysts for energy conversion devices and offers the in-operando technique for the analysis of catalysts in various operating temperatures.