Hierarchical peony-like FeCo-NC with conductive network and highly active sites as efficient electrocatalyst for rechargeable Zn-air battery

作者：Yiyan Wang, Anuj Kumar, Mang Ma, Yin Jia, Yu Wang, Ying Zhang, Guoxin Zhang, Xiaoming Sun, Zifeng Yan · 发表于：Nano Research · 年份：2020 · DOI：10.1007/s12274-020-2751-7 · 被引用次数：117 · 研究领域：Electrocatalysts for Energy Conversion、Advanced battery technologies research、Supercapacitor Materials and Fabrication

Carbon materials featuring hierarchical pores and atomically dispersed metal sites are promising catalysts for energy storage and conversion applications. Herein, we developed a facile strategy to construct functional carbon materials with a fluffy peony-like structure and dense binary FeCo-N x active sites (termed as f-FeCo-CNT). By regulating the metal content in precursors, a three-dimensional (3D) interconnected conductive carbon nanotubes network was in-situ formed throughout the atomically dispersed FeCo-NC matrix during pyrolysis. Taking advantage of rich pore hierarchy and co-existence of highly active FeCo-N x sites and beneficial FeCo alloy nanoparticles, the f-FeCo-CNT material exhibited excellent bifunctional performance towards oxygen reduction reaction/oxygen evolution reactions (ORR/OER) with respect to the atomically dispersed FeCo-NC (SA-f-FeCo-NC) and commercial Pt/C+RuO 2 mixture, surpassing the SA-f-FeCo-NC with a 20 mV higher ORR half-wave potential and a 100 mV lower OER overpotential (at 10.0 mA/cm 2 ). Remarkably, the f-FeCo-CNT-assembled Zn-air battery (ZAB) possessed a maximum specific power of 195.8 mW/cm 2 , excellent rate capability, and very good cycling stability at large current density of 20.0 mA/cm 2 . This work provides a facile and feasible synthetic strategy of constructing low-cost cathode materials with excellent comprehensive ZAB performance.