Molten-salt-assisted synthesis of onion-like Co/CoO@FeNC materials with boosting reversible oxygen electrocatalysis for rechargeable Zn-air battery

Yingjie Chen; Chong Gong; Zhihao Shi; Di Chen; Xing Chen; Qian Zhang; Beili Pang; Jianguang Feng; Liyan Yu; Lifeng Dong

doi:10.1016/j.jcis.2021.03.145

Molten-salt-assisted synthesis of onion-like Co/CoO@FeNC materials with boosting reversible oxygen electrocatalysis for rechargeable Zn-air battery

J Colloid Interface Sci. 2021 Aug 15:596:206-214. doi: 10.1016/j.jcis.2021.03.145. Epub 2021 Mar 29.

Authors

Yingjie Chen¹, Chong Gong¹, Zhihao Shi¹, Di Chen², Xing Chen¹, Qian Zhang¹, Beili Pang¹, Jianguang Feng³, Liyan Yu⁴, Lifeng Dong⁵

Affiliations

¹ College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042, China.
² Shandong Engineering Research Center of Green and High-value Marine Fine Chemical, Weifang University of Science and Technology, Shouguang 262700, China.
³ College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042, China. Electronic address: fengjg@qust.edu.cn.
⁴ College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042, China. Electronic address: liyanyu@qust.edu.cn.
⁵ College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042, China; Department of Physics, Hamline University, St. Paul 55104, USA. Electronic address: DongLifeng@qust.edu.cn.

PMID: 33845228
DOI: 10.1016/j.jcis.2021.03.145

Abstract

A melt-salt-assisted method is utilized to construct an onion-like hybrid with Co/CoO nanoparticles embedded in graphitic Fe-N-doped carbon shells (Co/CoO@FeNC) as a bifunctional electrocatalyst. The iron-polypyrrole (Fe-PPy) is firstly prepared with a reverse emulsion. Direct pyrolysis of Fe-PPy yields turbostratic Fe-N-doped carbon (FeNC) with excellent oxygen reduction reaction (ORR) electrocatalysis, while the melt salt (CoCl₂) mediated pyrolysis of Fe-PPy obtains onion-like Co/CoO@FeNC with a reversible overvoltage value of 0.695 V, largely superior to Pt/C and IrO₂ (0.771 V) and other Co-based catalysts reported so far. The ORR activity is mainly due to the graphitic FeNC and further enhanced by CoN_x bonds, whereas the oxygen evolution reaction (OER) activity is principally due to the Co/CoO composite. Concurrently, Co/CoO@FeNC as cathode catalyst enables Zn-air battery with a high open circuit voltage of 1.42 V, a peak power density of 132.8 mW cm^-2, a specific capacity of 813 mAh g_Zn^-1, and long-term stability.

Keywords: Core-shell; Molten salt; Onion-like carbon; Oxygen evolution reaction (OER); Oxygen reduction reaction (ORR).