Dissecting graphene capacitance in electrochemical cell

Sheng Sun, Yue Qi, Tong Yi Zhang

Research output: Contribution to journalArticle

  • 10 Citations

Abstract

Quantum capacitance of graphene plays a significant role for graphene's applications in electrochemical devices and sensors, while the determination of these basic characters of Dirac point, Fermi energy, quantum capacitance, etc is still a subject of considerable debate in both experiments and simulations. Here, we report joint first-principles/continuum calculations (JFPCCs) on a monolayer graphene electrode immersed in an electrolyte coupled with a reference electrode under an applied potential. The JFPCCs gave the Fermi level, charge density on graphene, Dirac point energy, electrostatic potential, electric double layer etc as a function of the applied potential with respect to the reference electrode. These results revealed the strongly coupled relationship between Fermi level change and Dirac point shift in electrochemical cell. The total capacitance of the electrochemical cell was dissected into the quantum capacitance of the graphene electrode and the capacitance of the electric double layer. Furthermore, simple and analytic formulas were proposed for the three capacitances, which predicted, in sufficient accuracy, the behavior of capacitance versus potential. These findings deepen the understanding of quantum capacitance of graphene, which will stimulate novel experimental and theoretical studies and boost the applications of graphene in electrochemical and energy areas.

LanguageEnglish (US)
Pages296-302
Number of pages7
JournalElectrochimica Acta
Volume163
DOIs
StatePublished - May 1 2015

Profile

Graphite
Electrochemical cells
Graphene
Capacitance
Fermi level
Electrodes
Charge density
Electrolytes
Electrostatics
Monolayers
Sensors
Electric potential

Keywords

  • Dirac point shift
  • Electrode/electrolyte interface
  • Graphene
  • Joint first-principles/continuum calculations
  • Quantum capacitance

ASJC Scopus subject areas

  • Electrochemistry
  • Chemical Engineering(all)

Cite this

Dissecting graphene capacitance in electrochemical cell. / Sun, Sheng; Qi, Yue; Zhang, Tong Yi.

In: Electrochimica Acta, Vol. 163, 01.05.2015, p. 296-302.

Research output: Contribution to journalArticle

Sun, Sheng ; Qi, Yue ; Zhang, Tong Yi. / Dissecting graphene capacitance in electrochemical cell. In: Electrochimica Acta. 2015 ; Vol. 163. pp. 296-302
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