Oxygen-vacancy-rich nickel-cobalt layered double hydroxide electrode for high-performance supercapacitors

Haoyan Liang; Henan Jia; Tiesong Lin; Zhaoyue Wang; Chun Li; Shulin Chen; Junlei Qi; Jian Cao; Weidong Fei; Jicai Feng

doi:10.1016/j.jcis.2019.06.095

Oxygen-vacancy-rich nickel-cobalt layered double hydroxide electrode for high-performance supercapacitors

J Colloid Interface Sci. 2019 Oct 15:554:59-65. doi: 10.1016/j.jcis.2019.06.095. Epub 2019 Jun 29.

Authors

Haoyan Liang¹, Henan Jia¹, Tiesong Lin¹, Zhaoyue Wang¹, Chun Li¹, Shulin Chen¹, Junlei Qi², Jian Cao¹, Weidong Fei¹, Jicai Feng¹

Affiliations

¹ State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China.
² State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China. Electronic address: jlqi@hit.edu.cn.

PMID: 31279273
DOI: 10.1016/j.jcis.2019.06.095

Abstract

The introduction of oxygen vacancies into electrode materials has been proven to be a valid way to enhance the electrochemical performance. However, the traditional methods to introduce oxygen vacancies require severe conditions that may be harmful to hydroxides. Herein, the oxygen vacancy-rich nickel-cobalt (NiCo) layered double hydroxide (denoted as V_o-NiCo LDH) nanowire array electrode is synthesized using the chemical reduction method. Owing to the reduction of NaBH₄ solution, we can create oxygen vacancies under milder conditions, thus avoiding any damage to the hydroxide. The as-synthesized electrode shows a specific capacitance of 1563.1 F g^-1 at 1 A g^-1, which is much higher than that of the pristine electrode (995.4 F g^-1 at 1 A g^-1). Moreover, the cycling performance and rate performance are also enhanced. The as-fabricated asymmetric supercapacitor (V_o-NiCo LDH//Fe₂O₃) is able to deliver a maximum energy density of 56.2 W h kg^-1 at a power density of 800 W kg^-1 with a voltage window of 1.6 V.

Keywords: Chemical reduction; NiCo LDH; Oxygen vacancies; Supercapacitor.