Deep-Breathing Honeycomb-like Co-Nx-C Nanopolyhedron Bifunctional Oxygen Electrocatalysts for Rechargeable Zn-Air Batteries

Zhaoqiang Li; Gaopeng Jiang; Ya-Ping Deng; Guihua Liu; Dezhang Ren; Zhen Zhang; Jianbing Zhu; Rui Gao; Yi Jiang; Dan Luo; Yanfei Zhu; Dai-Huo Liu; Altamash M Jauhar; Huile Jin; Yongfeng Hu; Shun Wang; Zhongwei Chen

doi:10.1016/j.isci.2020.101404

Deep-Breathing Honeycomb-like Co-N_x-C Nanopolyhedron Bifunctional Oxygen Electrocatalysts for Rechargeable Zn-Air Batteries

iScience. 2020 Aug 21;23(8):101404. doi: 10.1016/j.isci.2020.101404. Epub 2020 Jul 23.

Authors

Zhaoqiang Li¹, Gaopeng Jiang², Ya-Ping Deng², Guihua Liu², Dezhang Ren², Zhen Zhang², Jianbing Zhu², Rui Gao², Yi Jiang², Dan Luo², Yanfei Zhu², Dai-Huo Liu², Altamash M Jauhar², Huile Jin³, Yongfeng Hu⁴, Shun Wang⁵, Zhongwei Chen⁶

Affiliations

¹ College of Chemistry and Materials Engineering, Institute of New Materials and Industrial Technologies, Wenzhou University, Wenzhou, Zhejiang 325035, P. R. China; Department of Chemical Engineering, Waterloo Institute for Nanotechnology, Waterloo Institute for Sustainable Energy, University of Waterloo, Waterloo, ON N2L 3G1, Canada.
² Department of Chemical Engineering, Waterloo Institute for Nanotechnology, Waterloo Institute for Sustainable Energy, University of Waterloo, Waterloo, ON N2L 3G1, Canada.
³ College of Chemistry and Materials Engineering, Institute of New Materials and Industrial Technologies, Wenzhou University, Wenzhou, Zhejiang 325035, P. R. China.
⁴ Canadian Light Source, University of Saskatchewan Saskatoon, Saskatchewan S7N 2V3, Canada.
⁵ College of Chemistry and Materials Engineering, Institute of New Materials and Industrial Technologies, Wenzhou University, Wenzhou, Zhejiang 325035, P. R. China. Electronic address: shunwang@wzu.edu.cn.
⁶ Department of Chemical Engineering, Waterloo Institute for Nanotechnology, Waterloo Institute for Sustainable Energy, University of Waterloo, Waterloo, ON N2L 3G1, Canada. Electronic address: zhwchen@uwaterloo.ca.

Abstract

Metal organic framework (MOF) derivatives have been extensively used as bifunctional oxygen electrocatalysts. However, the utilization of active sites is still not satisfactory owing to the sluggish mass transport within their narrow pore channels. Herein, interconnected macroporous channels were constructed inside MOFs-derived Co-N_x-C electrocatalyst to unblock the mass transfer barrier. The as-synthesized electrocatalyst exhibits a honeycomb-like morphology with highly exposed Co-N_x-C active sites on carbon frame. Owing to the interconnected ordered macropores throughout the electrocatalyst, these active sites can smoothly "exhale/inhale" reactants and products, enhancing the accessibility of active sites and the reaction kinetics. As a result, the honeycomb-like Co-N_x-C displayed a potential difference of 0.773 V between the oxygen evolution reaction potential at 10 mA cm^-2 and the oxygen reduction reaction half-wave potential, much lower than that of bulk-Co-N_x-C (0.842 V). The rational modification on porosity makes such honeycomb-like MOF derivative an excellent bifunctional oxygen electrocatalyst in rechargeable Zn-air batteries.

Keywords: Inorganic materials; catalysis; electrochemical energy storage.