Self-Recovery Chemistry and Cobalt-Catalyzed Electrochemical Deposition of Cathode for Boosting Performance of Aqueous Zinc-Ion Batteries

Yijun Zhong; Xiaomin Xu; Jean-Pierre Veder; Zongping Shao

doi:10.1016/j.isci.2020.100943

Self-Recovery Chemistry and Cobalt-Catalyzed Electrochemical Deposition of Cathode for Boosting Performance of Aqueous Zinc-Ion Batteries

iScience. 2020 Mar 27;23(3):100943. doi: 10.1016/j.isci.2020.100943. Epub 2020 Feb 27.

Authors

Yijun Zhong¹, Xiaomin Xu¹, Jean-Pierre Veder², Zongping Shao³

Affiliations

¹ WA School of Mines: Minerals, Energy and Chemical Engineering (WASM-MECE), Curtin University, Perth, WA 6845, Australia.
² John de Laeter Centre, Curtin University, Perth, WA 6102, Australia.
³ WA School of Mines: Minerals, Energy and Chemical Engineering (WASM-MECE), Curtin University, Perth, WA 6845, Australia; State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing, Jiangsu 210009, P.R. China. Electronic address: zongping.shao@curtin.edu.au.

Abstract

Rechargeable Zn-ion batteries working with manganese oxide cathodes and mild aqueous electrolytes suffer from notorious cathode dissolution during galvanostatic cycling. Herein, for the first time we demonstrate the dynamic self-recovery chemistry of manganese compound during charge/discharge processes, which strongly determines the battery performance. A cobalt-modified δ-MnO₂ with a redox-active surface shows superior self-recovery capability as a cathode. The cobalt-containing species in the cathode enable efficient self-recovery by continuously catalyzing the electrochemical deposition of active Mn compound, which is confirmed by characterizations of both practical coin-type batteries and a new-design electrolyzer system. Under optimized condition, a high specific capacity over 500 mAh g^-1 is achieved, together with a decent cycling performance with a retention rate of 63% over 5,000 cycles. With this cobalt-facilitated deposition effect, the battery with low concentration (0.02 M) of additive Mn²⁺ in the electrolyte (only 12 atom % to the overall Mn) maintains decent capacity retention.

Keywords: Catalysis; Electrochemical Energy Storage; Electrochemical Materials Science.