Improvement of the pseudocapacitive performance of cobalt oxide-based electrodes for electrochemical capacitors

Mojtaba Mirzaeian*, Nazym Akhanova, Maratbek Gabdullin, Zhanar Kalkozova, Aida Tulegenova, Shyryn Nurbolat, Khabibulla Abdullin*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

30 Citations (Scopus)
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Abstract

Cobalt oxide nanopowders are synthesized by the pyrolysis of aerosol particles of water solution of cobalt acetate. Cobalt nanopowder is obtained by subsequent reduction of obtained cobalt oxide by annealing under a hydrogen atmosphere. The average crystallite size of the synthesized porous particles ranged from 7 to 30 nm, depending on the synthesis temperature. The electrochemical characteristics of electrodes based on synthesized cobalt oxide and reduced cobalt oxide are investigated in an electrochemical cell using a 3.5 M KOH solution as the electrolyte. The results of electrochemical measurements show that the electrode based on reduced cobalt oxide (Re-Co3O4) exhibits significantly higher capacity, and lower Faradaic charge–transfer and ion diffusion resistances when compared to the electrodes based on the initial cobalt oxide Co3O4. This observed effect is mainly due to a wide range of reversible redox transitions such as Co(II) ↔ Co(III) and Co(III) ↔ Co(IV) associated with different cobalt oxide/hydroxide species formed on the surface of metal particles during the cell operation; the small thickness of the oxide/hydroxide layer providing a high reaction rate, and also the presence of a metal skeleton leading to a low series resistance of the electrode.
Original languageEnglish
Article number5228
Number of pages16
JournalEnergies
Volume13
Issue number19
DOIs
Publication statusPublished - 8 Oct 2020

Keywords

  • cobalt oxide nanoparticles
  • reduced cobalt oxide
  • core-shell nanoparticles
  • electrode material
  • supercapacitor

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