Release Time:2019-03-12  Hits:

Indexed by:Journal Article

Date of Publication:2018-01-01

Journal:Chemphyschem : a European journal of chemical physics and physical chemistry

Included Journals:SCIE、PubMed

Volume:19

Issue:13

Page Number:1579-1583

ISSN:1439-7641

Key Words:density functional calculations; electrochemistry; graphene oxide; quantum capacitance; supercapacitors

Summary:Graphene oxide has become an attractive electrode-material candidate for supercapacitors thanks to its higher specific capacitance compared to graphene. The quantum capacitance makes relative contributions to the specific capacitance, which is considered as the major limitation of graphene electrodes, while the quantum capacitance of graphene oxide is rarely concerned. This study explores the quantum capacitance of graphene oxide, which bears epoxy and hydroxyl groups on its basal plane, by employing density functional theory (DFT) calculations. The results demonstrate that the total density of states near the Fermi level is significantly enhanced by introducing oxygen-containing groups, which is beneficial for the improvement of the quantum capacitance. Moreover, the quantum capacitances of the graphene oxide with different concentrations of these two oxygen-containing groups are compared, revealing that more epoxy and hydroxyl groups result in a higher quantum capacitance. Notably, the hydroxyl concentration has a considerable effect on the capacitive behavior. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.