Porous 3D graphene/multi-walled carbon nanotubes electrodes with improved mass transport and kinetics towards VO2+/VO2+ redox couple

Maryam AlNahyan, Ibrahim Mustafa, Amal Alghaferi, Faisal Almarzooqi

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Conventionally, production of 3D graphene (3DG) results in non-uniform particle size and random structures. Although important, the effect of the 3DG particle size on the kinetics of CNT electrodes toward the Vanadium Redox Flow Battery (VRFB) electrolyte has not been investigated. Herein, we manipulate in-lab fabricated CNT sheets with variable particle sizes of electroactive porous 3D graphene (3DG) additives, resulting in variable porous characteristics due to the spacing effect of the 3DG within the as-fabricated CNT fibers. We show that the particle size of 3DG affects both the kinetics and the mass transport capabilities of buckypaper electrodes. The results show that the 3DG additives did not only act as spacers between the CNT fibers opening up channels for increased mass flow to occur, but also improved the heterogeneous rate constants of the reactions. The improvement in kinetics, however, became more significant as the 3DG particle size decreased. Nevertheless, the results also suggest that the use of electroactive materials with controlled particle sizes is a promising strategy for the preparation of porous CNT materials for VRFBs.

Original languageBritish English
Article number138449
JournalElectrochimica Acta
Volume385
DOIs
StatePublished - 20 Jul 2021

Keywords

  • 3D graphene
  • Buckypaper
  • Multiwalled carbon nanotube
  • Vanadium redox flow battery

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