Supercapacitor performance of porous nickel cobaltite nanosheets

Xin Chen; Rui Xie; Hui Li; F Jaber; F Musharavati; E Zalnezhad; S Bae; K S Hui; K N Hui

doi:10.1038/s41598-020-75946-1

Supercapacitor performance of porous nickel cobaltite nanosheets

Sci Rep. 2020 Nov 3;10(1):18956. doi: 10.1038/s41598-020-75946-1.

Authors

Xin Chen¹, Rui Xie², Hui Li³, F Jaber⁴, F Musharavati⁵, E Zalnezhad⁶, S Bae⁷, K S Hui⁸, K N Hui⁹

Affiliations

¹ Department of Mechanical Convergence Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul, 04763, South Korea.
² Department of Electronic Information, Shandong Xiandai University, Jinan, 250000, People's Republic of China.
³ Department of Chemical Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul, 04763, South Korea.
⁴ Department of Biomedical Engineering, Ajman University, 2758, Ajman, UAE.
⁵ Department of Mechanical and Industrial Engineering, College of Engineering, Qatar University, 2713, Doha, Qatar.
⁶ Department of Chemical and Biomedical Engineering, University of Texas At San Antonio, San Antonio, TX, USA. erfan.zalnezhad@utsa.edu.
⁷ Department of Architectural Engineering, Hanyang University, Seoul, 04763, Korea. sbae@hanyang.ac.kr.
⁸ School of Engineering, University of East Anglia, Norwich, NR4 7TJ, UK.
⁹ Joint Key Laboratory of the Ministry of Education, Institute of Applied Physics and Materials Engineering, University of Macau, Avenida da Universidade, Taipa, Macau SAR, 999078, China.

Abstract

In this work, nickel cobaltite (NiCo₂O₄) nanosheets with a porous structure were fabricated on nickel foam as a working electrode for supercapacitor applications. The nanosheets were fabricated by electrochemical deposition of nickel-cobalt hydroxide on the nickel foam substrate at ambient temperature in a three-electrode cell followed by annealing at 300 °C to transform the coating into a porous NiCo₂O₄ nanosheet. Field emission scanning electron microscopy and transmission electron microscopy revealed a three-dimensional mesoporous structure, which facilitates ion transport and electronic conduction for fast redox reactions. For one cycle, the NiCo₂O₄ electrodeposited nickel foam has a high specific capacitance (1734.9 F g^-1) at a current density (CD) of 2 A g^-1. The electrode capacitance decreased by only approximately 12.7% after 3500 cycles at a CD of 30 A g^-1. Moreover, a solid-state asymmetric supercapacitor (ASC) was built utilising the NiCo₂O₄ nanosheets, carbon nanotubes, and a polyvinyl alcohol-potassium hydroxide gel as the anode, cathode, and solid-state electrolyte, respectively. The ASC displayed great electrochemical properties with a 42.25 W h kg^-1 energy density at a power density of 298.79 W kg^-1.