A novel approach to fabricate carbon-sphere-intercalated holey graphene electrode for high-energy-density electrochemical capacitors

Wu, Shuxing, San Hui, Kwan ORCID: https://orcid.org/0000-0001-7089-7587, Nam Hui, Kwun, Moon Yun, Je and Ho Kim, Kwang (2017) A novel approach to fabricate carbon-sphere-intercalated holey graphene electrode for high-energy-density electrochemical capacitors. Chemical Engineering Journal, 317. 461–470. ISSN 1385-8947

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Abstract

Desirable porous structure and huge ion-accessible surface area are crucial for rapid electronic and ionic pathway electrodes in high-performance graphene-based electrochemical capacitors. However, graphene nanosheets tend to aggregate and restack because of van der Waals interaction among graphene sheets, resulting in the loss of ion-accessible surface area and unsatisfactory electrochemical performance. To resolve this daunting challenge, a novel approach is developed for the self-assembly of holey graphene sheets intercalated with carbon spheres (H-GCS) to obtain freestanding electrodes by using a simple vacuum filtration approach and a subsequent KOH activation process. Through the introduction of carbon spheres as spacers, the restacking of reduced graphene oxide (rGO) sheets during the filtration process is mitigated efficiently. Pores on rGO sheets produced by subsequent KOH activation also provide rapid ionic diffusion kinetics and high ion-accessible electrochemical surface area, both of which favor the formation of electric double-layer capacitance. Furthermore, a higher degree of graphitization of CSs in H-GCS thin film improves the electrical conductivity of the H-GCS electrode. The H-GCS electrode exhibits 207.1 F g−1 of specific capacitance at a current density of 1 A g−1 in 6 M KOH aqueous electrolyte. Moreover, the symmetric electrochemical capacitor assembled with H-GCS electrodes and organic electrolyte is capable of delivering a maximum energy density of 29.5 Wh kg−1 and a power density of 22.6 kW kg−1.

Item Type:	Article
Uncontrolled Keywords:	electrochemical capacitor,high-energy-density,holey graphene,carbon sphere
Faculty \ School:	Faculty of Science > School of Mathematics (former - to 2024)
UEA Research Groups:	Faculty of Science > Research Groups > Energy Materials Laboratory
Related URLs:	http://linkinghub.elsevier.com/retrieve/...
Depositing User:	Pure Connector
Date Deposited:	11 Feb 2017 02:17
Last Modified:	27 Nov 2024 10:19
URI:	https://ueaeprints.uea.ac.uk/id/eprint/62432
DOI:	10.1016/j.cej.2017.02.040

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