Synergizing Single-Atom and Carbon-Encapsulated Nanoparticle Of Fe For Efficient Oxygen Reduction and Durable Zn-Air Batteries

Abstract

Addressing the sluggish oxygen reduction reaction (ORR) bottleneck in Zn-air batteries is crucial for their large-scale deployment. Fe-N/C catalysts emerge as promising alternatives to precious Pt-based counterparts. Herein, carbon-encapsulated Fe nanoparticles decorated with Fe-N/C (denoted as FeNPs@Fe-N/C) are rationally designed and synthesized via controlled pyrolysis. The FeNPs@Fe-N/C catalyst achieves excellent ORR performance in alkaline solution with a half-wave potential (E1/2) of 0.914 VRHE. This work reveals that the precise incorporation of carbon-encapsulated Fe nanoparticles substantially improves the catalytic activity of Fe-N/C catalysts. Meanwhile, the FeNPs@Fe-N/C as the of Zn-air battery cathode delivers an impressive peak power density of 175.7 mW cm-2 and excellent stability over 500h, surpassing the Pt/C benchmarks. Density functional theory calculations reveal that the introduced carbon-encapsulated Fe nanoparticles facilitate electron transfer to the catalytic site via d-band center modulation, thus boosting ORR performance. This research paves the way for future design strategies employing nanoparticle engineering for highly efficient electrocatalysts.

Keywords: Fe-N/C, ORR, Zn-air battery, nanoparticle