Tuning the coordination environment of Fe atoms enables 3D porous Fe/N-doped carbons as bifunctional electrocatalyst for rechargeable zinc-air battery

Yaling Huang; Yafei Zhang; Jiayu Hao; Yanqiu Wang; Jiawen Yu; Yang Liu; Zhongliang Tian; Ting-Shan Chan; Min Liu; Wenzhang Li; Jie Li

doi:10.1016/j.jcis.2022.09.066

Tuning the coordination environment of Fe atoms enables 3D porous Fe/N-doped carbons as bifunctional electrocatalyst for rechargeable zinc-air battery

J Colloid Interface Sci. 2022 Dec 15;628(Pt A):1067-1076. doi: 10.1016/j.jcis.2022.09.066. Epub 2022 Sep 16.

Authors

Yaling Huang¹, Yafei Zhang², Jiayu Hao¹, Yanqiu Wang¹, Jiawen Yu¹, Yang Liu¹, Zhongliang Tian³, Ting-Shan Chan⁴, Min Liu⁵, Wenzhang Li⁶, Jie Li⁷

Affiliations

¹ School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China.
² School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China; Changsha Uranium Geology Research Institute, China National Nuclear Corporation, China.
³ School of Metallurgy and Environment, Central South University, Changsha 410083, China.
⁴ National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan.
⁵ School of Physics and Electronics, Central South University, Changsha 410083, China.
⁶ School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China; Hunan Provincial Key Laboratory of Chemical Power Sources, Central South University, Changsha 410083, China. Electronic address: liwenzhang@csu.edu.cn.
⁷ School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China. Electronic address: lijieliu@csu.edu.cn.

PMID: 36163054
DOI: 10.1016/j.jcis.2022.09.066

Abstract

As one of the most promising candidates for power sources, the rechargeable Zn-air batteries have attracted much attention due to their high energy density. However, Zn-air batteries suffer from sluggish kinetics of oxygen reduction (ORR) and oxygen evolution reaction (OER) during the discharge and charge process. Herein, a FeN₂-doped carbon with a unique three-dimensional (3D) porous structure (CeO₂-FeNC-5) was synthesized as an electrocatalyst for Zn-air batteries by one-step pyrolysis and introducing CeO₂ to tune the coordination environment of Fe atoms. Extended X-ray absorption fine structure (EXAFS) results indicate that the introduction of CeO₂ can convert FeN₃ moieties into FeN₂ moieties. The CeO₂-FeNC-5 exhibits a more positive half-wave potential of 0.902 V for ORR, and a low overpotential of 0.327 V at 10 mA cm^-2 for OER. Furthermore, the Zn-air battery with CeO₂-FeNC-5 achieve a maximum power density (169 mW cm^-2), a high open voltage platform (1.47 V) and superior cycling stability (200 h). The unique 3D porous structure provides channels for mass transport and exposes sufficient active sites to facilitate the ORR and OER processes. Calculations prove that FeN₂ moieties are beneficial to O₂ adsorption on Fe/N-doped carbon surface. This work provides an effective strategy for designing and synthesizing FeN_x-doped carbon matrix electrocatalysts for sustainable metal-air batteries.

Keywords: 3D porous carbon; CeO(2); FeN(2) moieties; Oxygen reduction reaction; Zinc-air battery.