Defective core-shell NiCo2S4/MnO2 nanocomposites for high performance solid-state hybrid supercapacitors

Jinhe Wei; Fei Hu; Xiong Shen; Bingkun Chen; Lin Chen; Zhongming Wang; Chenglong Lv; Qiuyun Ouyang

doi:10.1016/j.jcis.2023.06.088

Defective core-shell NiCo₂S₄/MnO₂ nanocomposites for high performance solid-state hybrid supercapacitors

J Colloid Interface Sci. 2023 Nov:649:665-674. doi: 10.1016/j.jcis.2023.06.088. Epub 2023 Jun 19.

Authors

Jinhe Wei¹, Fei Hu¹, Xiong Shen¹, Bingkun Chen¹, Lin Chen¹, Zhongming Wang¹, Chenglong Lv¹, Qiuyun Ouyang²

Affiliations

¹ Key Laboratory of In-Fiber Integrated Optics, Ministry Education of China, and College of Physics and Optoelectronic Engineering, Harbin Engineering University, Harbin 150001, China.
² Key Laboratory of In-Fiber Integrated Optics, Ministry Education of China, and College of Physics and Optoelectronic Engineering, Harbin Engineering University, Harbin 150001, China. Electronic address: qyouyang@hrbeu.edu.cn.

PMID: 37379790
DOI: 10.1016/j.jcis.2023.06.088

Abstract

The roles of oxygen vacancies to enhance the electrochemical performance were not clearly explained in comprehensive research. Herein, the vertically oriented NiCo₂S₄/MnO₂ core-shell nanocomposites are in situ grown on the nickel foam (NF) surface and activated by oxygen vacancy engineering via a chemical reduction method. The scanning electron microscope (SEM) and transmission electron microscope (TEM) results show the shell-MnO₂ is well coated on the core-NiCo₂S₄. The hierarchical core-shell nanostructures synergistically increase conductivity and provide rich faradaic redox chemical reactions. Moreover, the density functional theory (DFT) calculations further indicate that the electronic properties and structure properties in NiCo₂S₄/MnO₂ electrode of reduction for 60 min (NiCo₂S₄/MnO₂-60) are effectively adjusted by introducing oxygen vacancies. Impressively, the NiCo₂S₄/MnO₂-60 electrode delivers substantially appreciable areal capacity of 2.13 mAh·cm^-2 couple with superior rate capability. The as-prepared high-performance electrode material can assemble into solid-state hybrid supercapacitor. The fabricated NiCo₂S₄/MnO₂-60//AC device exhibits an exceptional energy density of 43.16 Wh·kg^-1 at a power density of 384.21 W·kg^-1 and satisfactory cyclic stability of 92.1 % at current density of 10 mA·cm^-2 after 10,000 cycles. In general, the work demonstrates the significance of NiCo₂S₄/MnO₂-60 as a highly redox active electrode material for future practical application in supercapacitors.

Keywords: Defect engineering; Density functional theory; Hybrid supercapacitor; NiCo(2)S(4)/MnO(2); Oxygen vacancy.