Fe,N-modulated carbon fibers aerogel as freestanding cathode catalyst for rechargeable Zn-Air battery

Freestanding air cathode catalyst with exceptional catalytic bifunctions for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is highly desirable for exploring rechargeable Zn-air batteries (ZABs) with low cost and high reliability. Here, a facile and scalable approach is demonstrated to prepare efficient and robust freestanding cathode catalyst that consists of dispersed Fe3C nanoparticles, rich Fe-N-x/N-C species and carbon fibers networks with large specific surface area, which is based on one-pot in-situ coupling of Fe and N induced active sites within bacterial cellulose-derived carbon fibers networks. Its bifunctional activity parameter (Delta E) for ORR and OER is 0.79 V, superior to those of single Fe- or N- modulated counterparts, and comparable to the state-of-the-art Pt/C + RuO2 catalyst (0.79 V). This material can be directly used as freestanding and binder-free catalyst layer, and as-assembled ZABs exhibit a larger peak power density (173 mW cm(-2)), higher specific capacity (717 mA h g(-1), 10 mA cm(-2)) and better cycle stability (negligible activity decay after 165 h charge/discharge cycles) than those of Pt/ C + RuO2-based devices, representing their potential applications in advanced energy conversion systems. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

A freestanding air cathode catalyst with exceptional catalytic bifunctions for both ORR and OER has been prepared using a facile and scalable method, showing superior performance compared to single Fe- or N-modulated counterparts and comparable to state-of-the-art Pt/C + RuO2 catalyst. This material exhibits potential applications in advanced energy conversion systems, with higher peak power density, specific capacity, and cycle stability than traditional Pt/C + RuO2-based devices.