Unusual formation of NiCo2O4@MnO2/nickel foam/MnO2 sandwich as advanced electrodes for hybrid supercapacitors

Chunli Guo; Jie Li; Yanting Chu; Haibo Li; Huaiping Zhang; Lifeng Hou; Yinghui Wei; Jing Liu; Shenglin Xiong

doi:10.1039/c9dt00696f

Unusual formation of NiCo₂O₄@MnO₂/nickel foam/MnO₂ sandwich as advanced electrodes for hybrid supercapacitors

Dalton Trans. 2019 Jun 7;48(21):7403-7412. doi: 10.1039/c9dt00696f. Epub 2019 Apr 17.

Authors

Chunli Guo¹, Jie Li¹, Yanting Chu², Haibo Li³, Huaiping Zhang¹, Lifeng Hou¹, Yinghui Wei¹, Jing Liu⁴, Shenglin Xiong²

Affiliations

¹ College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan, Shanxi 030024, P.R. China.
² Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, and State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, PR China. chexsl@sdu.edu.cn.
³ School of Materials Science and Engineering, Liaocheng University, Liaocheng, Shandong 252059, PR China.
⁴ College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042, China.

PMID: 30994136
DOI: 10.1039/c9dt00696f

Abstract

A facile three-step method is designed for large-scale preparation of a NiCo₂O₄@MnO₂/nickel foam/MnO₂ sandwich architecture with robust adhesion as an advanced electrode for high-performance supercapacitors. The synthesis contains the hydrothermal reaction of a cobalt-nickel hydroxide precursor on a nickel foam (NF) support and subsequent thermal conversion into spinel mesoporous NiCo₂O₄ nanowire arrays, followed by a hydrothermal oxidation reaction to synthesize NiCo₂O₄@MnO₂/nickel foam/MnO₂ sandwiches. Moreover, the tactics reported in this study enable easy control of the growth of NiCo₂O₄ on one side of the NF and MnO₂ nanosheets on both sides of the NF to obtain novel NiCo₂O₄@MnO₂/nickel foam/MnO₂ sandwiches. Because of the unusual structural and compositional features, the obtained NiCo₂O₄@MnO₂/nickel foam/MnO₂ sandwiches manifest excellent performance with high specific capacitance (1.70 C cm^-2 at 2 mA cm^-2), exceptional rate capability (78.5% retention at 20 mA cm^-2) and ultralong cycling stability (91% retention over 30 000 cycles at 20 mA cm^-2) as a battery-type electrode material for supercapacitors. When further assembled into an aqueous hybrid supercapacitor, it can deliver an energy density of 53.5 W h kg^-1 at a power density of 80 W kg^-1 and 20.7 W h kg^-1 at 8 kW kg^-1. This novel sandwich electrode provides a new idea for improving the electrochemical performance of hybrid supercapacitors.