Graphite Nanoarrays-Confined Fe and Co Single-Atoms within Graphene Sponges as Bifunctional Oxygen Electrocatalyst for Ultralong Lasting Zinc-Air Battery
2020
Chen, Chang | Li, Yifan | Cheng, Dan | He, Hua | Zhou, Kebin
The inferior stability of bifunctional oxygen electrocatalysts in the air cathode is one of the main obstacles that impedes the commercialization of zinc-air batteries (ZABs). This work describes a self-assembly technique combined with subsequent calcination to prepare a bifunctional oxygen electrocatalyst of graphite nanoarrays-confined Fe and Co single-atoms within graphene sponges (FeCo-NGS). Specifically, graphene sponges overspread with graphite nanoarrays as a structure regulation, which can prevent the metal single-atoms from aggregating and accelerate the mass/electron transfer, provides a guarantee for the long-term operation. Furthermore, M-N₄ (M = Fe/Co) as the intrinsic activity regulation can effectively drive the heterogeneous oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) catalytic processes. Thanks to the rationally designed regulations, FeCo-NGS shows both extraordinary electrocatalytic activity for ORR and OER, even outperforming commercial Pt/C and IrO₂. Remarkably, ZABs with FeCo-NGS air cathode demonstrate a record-breaking cycle lifetime of more than 1500 h (over 9000 cycles) at 10 mA cm–² with a small charge–discharge gap.
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