Mussel-inspired one-pot synthesis of transition metal and nitrogen co-doped carbon (M/N-C) as efficient oxygen catalysts for Zn-air batteries

Bing Li, Ye Chen, Xiaoming Ge, Jianwei Chai, Xiao Zhang, T. S.Andy Hor, Guojun Du, Zhaolin Liu, Hua Zhang, Yun Zong

Research output: Journal article publicationJournal articleAcademic researchpeer-review

85 Citations (Scopus)

Abstract

Transition metal and nitrogen co-doping into carbon is an effective approach to promote the catalytic activities towards the oxygen reduction reaction (ORR) and/or oxygen evolution reaction (OER) in the resultant electrocatalysts, M/N-C. The preparation of such catalysts, however, is often complicated and in low yield. Herein we report a robust approach for easy synthesis of M/N-C hybrids in high yield, which includes a mussel-inspired polymerization reaction at room temperature and a subsequent carbonization process. With the introduction of selected transition metal salts into an aqueous solution of dopamine (DA), the obtained mixture self-polymerizes to form metal-containing polydopamine (M-PDA) composites, e.g. Co-PDA, Ni-PDA and Fe-PDA. Upon carbonization at elevated temperatures, these metal-containing composites were converted into M/N-C, i.e. Co-PDA-C, Ni-PDA-C and Fe-PDA-C, respectively, whose morphologies, chemical compositions, and electrochemical performances were fully studied. Enhanced ORR activities were found in all the obtained hybrids, with Co-PDA-C standing out as the most promising catalyst with excellent stability and catalytic activities towards both ORR and OER. This was further proven in Zn-air batteries (ZnABs) in terms of discharge voltage stability and cycling performance. At a discharge-charge current density of 2 mA cm-2 and 1 h per cycle, the Co-PDA-C based ZnABs were able to steadily cycle up to 500 cycles with only a small increase in the discharge-charge voltage gap which notably outperformed Pt/C; at a discharge current density of 5 mA cm-2, the battery continuously discharged for more than 540 h with the discharge voltage above 1 V and a voltage drop rate of merely 0.37 mV h-1. With the simplicity and scalability of the synthetic approach and remarkable battery performances, the Co-PDA-C hybrid catalyst is anticipated to play an important role in practical ZnABs.

Original languageEnglish
Pages (from-to)5067-5075
Number of pages9
JournalNanoscale
Volume8
Issue number9
DOIs
Publication statusPublished - 7 Mar 2016
Externally publishedYes

ASJC Scopus subject areas

  • Materials Science(all)

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