Magnesium-regulated oxygen vacancies of cobalt-nickel layered double hydroxide nanosheets for ultrahigh performance asymmetric supercapacitors

Guolang Zhou; Xiaoliang Gao; Shizheng Wen; Xinglong Wu; Lili Zhang; Tianshi Wang; Pusu Zhao; Jingzhou Yin; Wenshuai Zhu

doi:10.1016/j.jcis.2021.12.087

Magnesium-regulated oxygen vacancies of cobalt-nickel layered double hydroxide nanosheets for ultrahigh performance asymmetric supercapacitors

J Colloid Interface Sci. 2022 Apr 15:612:772-781. doi: 10.1016/j.jcis.2021.12.087. Epub 2021 Dec 29.

Authors

Guolang Zhou¹, Xiaoliang Gao², Shizheng Wen³, Xinglong Wu⁴, Lili Zhang⁵, Tianshi Wang², Pusu Zhao², Jingzhou Yin⁶, Wenshuai Zhu⁷

Affiliations

¹ School of Chemistry and Chemical Engineering, Huaiyin Normal University, Huai'an, Jiangsu 223001, PR China; School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, PR China.
² School of Chemistry and Chemical Engineering, Huaiyin Normal University, Huai'an, Jiangsu 223001, PR China.
³ School of Physics and Electronic Electrical Engineering, Huaiyin Normal University, Huai'an, Jiangsu 223001, PR China.
⁴ School of Chemistry, Northeast Normal University, Changchun, Jilin 130024, PR China.
⁵ School of Chemistry and Chemical Engineering, Huaiyin Normal University, Huai'an, Jiangsu 223001, PR China. Electronic address: zll@hytc.edu.cn.
⁶ School of Chemistry and Chemical Engineering, Huaiyin Normal University, Huai'an, Jiangsu 223001, PR China. Electronic address: jingzhouyin@hytc.edu.cn.
⁷ School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, PR China. Electronic address: zhuws@ujs.edu.cn.

PMID: 35032928
DOI: 10.1016/j.jcis.2021.12.087

Abstract

Rational design of layered double hydroxide (LDH) electrodes is of great significance for high-performance supercapacitors (SCs). Herein, ultrathin cobalt-nickel-magnesium layered double hydroxide (CoNiMg-LDH) nanosheets with plentiful oxygen vacancies are synthesized via sacrificial magnesium-based replacement reaction at room temperature. Self-doping and mild reduction of magnesium can significantly increase the concentration of oxygen vacancies in CoNiMg-LDH, which promotes the electrochemical charge transfer efficiency and enhances the adsorption ability of electrolytes. Density functional theory (DFT) calculations also indicate that Mg²⁺ doping can decrease the formation energy of oxygen vacancies in CoNiMg-LDH nanosheets, which increases the concentration of oxygen vacancies. Thus, the assembled asymmetric supercapacitor CoNiMg-LDH//Actived Carbon accomplishes a superior capacity of ∼ 333 C g^-1 (208 F g^-1) at 1 A g^-1 and presents a gravimetric energy density of 73.9 Wh kg^-1 at 0.8 kW kg^-1. It presents only 13% capacity loss at 20 A g^-1 after 5000 cycles. This discovery emphasizes the positive role of magnesium in regulating oxygen vacancies to improve the performance of supercapacitors, which should be beneficial for extending the scope of superior SCs active materials.

Keywords: CoNiMg-LDH; Magnesium; Oxygen vacancies; Supercapacitors.