Charge-Compensation in a Displacement Mg2+ Storage Cathode through Polyselenide-Mediated Anion Redox

Xuelian Qu; Aobing Du; Tao Wang; Qingyu Kong; Guodong Chen; Zhonghua Zhang; Jingwen Zhao; Xin Liu; Xinhong Zhou; Shanmu Dong; Guanglei Cui

doi:10.1002/anie.202204423

Charge-Compensation in a Displacement Mg²⁺ Storage Cathode through Polyselenide-Mediated Anion Redox

Angew Chem Int Ed Engl. 2022 Jul 18;61(29):e202204423. doi: 10.1002/anie.202204423. Epub 2022 May 18.

Authors

Xuelian Qu^{1

2}, Aobing Du¹, Tao Wang¹, Qingyu Kong³, Guodong Chen^{1

2}, Zhonghua Zhang⁴, Jingwen Zhao^{1

5}, Xin Liu^{1

2

6}, Xinhong Zhou⁷, Shanmu Dong^{1

5}, Guanglei Cui^{1

6}

Affiliations

¹ Qingdao Industrial Energy Storage Research Institute, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, P. R. China.
² School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing, 100190, P. R. China.
³ Société Civile Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192, GIF-sur-Yvette CEDEX, France.
⁴ College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, 266042, P. R. China.
⁵ Shandong Energy Institute, Qingdao, 266101, P. R. China.
⁶ School of Future Technology, University of Chinese Academy of Sciences, Beijing, 100190, P. R. China.
⁷ College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, 266042, P. R. China.

PMID: 35419905
DOI: 10.1002/anie.202204423

Abstract

Chalcogenides have been viewed as important conversion-type Mg²⁺ -storage cathodes to fulfill the high volumetric energy density promise of magnesium (Mg) batteries. However, the low initial Columbic efficiency and the rapid capacity degradation remain challenges for the chalcogenide cathodes, as the clear Mg²⁺ -storage mechanism has yet to be clarified. Herein, we illustrate that the charge storage mechanism of the Cu_2-x Se cathode is a reversible displacement reaction along with a polyselenide (PSe) mediated solution process of anion-compensation. The unique anion redox improves charge storage, while the dissolution of PSe also leads to performance degradation. To address this issue, we introduce Mo₆ S₈ into the Cu_2-x Se cathode to immobilize PSe, which significantly improves performance, especially the reversible capacity (from 140 mAh g^-1 to 220 mAh g^-1 ). This work provides inspiration for the modification of the Mg²⁺ -storage cathode, which is a milestone for high-performance Mg batteries.

Keywords: Anion Compensation; Displacement Reaction; Electrochemistry; Magnesium Batteries; Polyselenide.

Abstract

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