Hierarchically structured electrode materials derived from metal-organic framework/vertical graphene composite for high-performance flexible asymmetric supercapacitors

Mingliang He and Gan Jet Hong Melvin and Mingxi Wang and Wanli Fan and Jingwen Lin and Xiaobo Chen and Keng Xu and Cailei Yuan and Yongyi Zhang and Fei Zhang and Zhipeng Wang (2023) Hierarchically structured electrode materials derived from metal-organic framework/vertical graphene composite for high-performance flexible asymmetric supercapacitors. Journal of Energy Storage, 70. pp. 1-10. ISSN 2352-152X

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Abstract

Low conductivity of metal-organic frameworks limits their applications in electrochemical energy storage and conversion. To overcome this shortcoming, we synthesized the zeolitic imidazolate framework-67 on the vertical graphene (VG) surface with abundant defects grown on carbon cloth (ZIF-67-VG-CC). Based on “one-for-two” strategy, the Co₃O₄ nanoparticles (Co3O4-VG-CC) and nanoporous carbon (NC-VG-CC) can be derived from ZIF67-VG-CC via selective pyrolysis in the controlled atmospheres. In the hierarchically structured Co₃O₄ -VG-CC and NC-VG-CC, the Co₃O₄ nanoparticles with a size of 20 nm and N-doped porous carbons were uniformly dispersed on the VG surface, as confirmed by electron microscopies. Both the Co₃O₄ -VG-CC and NC-VG-CC yield high specific capacitance and excellent rate capability. After assembling these two electrodes to make an asymmetric supercapacitor, the Co₃O₄ -VG-CC//NC-VG-CC delivered a maximum energy density of 43.75 Wh/kg at a power density of 5.2 kW/kg as well as excellent cycling stability with 91.5 % specific capacitance retained after 20,000 charge-discharge cycles. All these results should be ascribed to that the VG sheets possess their high electrical conductivity and 3D network structure, and provide the hierarchical supports for the uniform distribution of the ZIF-67-dervied Co₃O₄ nanoparticles and NC materials, which are beneficial to the fast electron and ion transfer in the electrodes.

Item Type:	Article
Keyword:	Vertical graphene, Metal-organic framework, Hierarchical structure electrodes, Flexible asymmetric supercapacitor
Subjects:	Q Science > QD Chemistry > QD1-999 Chemistry > QD146-197 Inorganic chemistry T Technology > TK Electrical engineering. Electronics Nuclear engineering > TK1-9971 Electrical engineering. Electronics. Nuclear engineering > TK7800-8360 Electronics
Department:	FACULTY > Faculty of Engineering
Depositing User:	SITI AZIZAH BINTI IDRIS -
Date Deposited:	17 Jun 2025 10:30
Last Modified:	17 Jun 2025 10:30
URI:	https://eprints.ums.edu.my/id/eprint/44162

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