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Substrate Effects in Graphene‐Based Electric Double‐Layer Capacitors: The Pivotal Interplays between Ions and Solvents
Author(s) -
Yang Huachao,
Bo Zheng,
Yang Jinyuan,
Kong Jing,
Chen Xia,
Yan Jianhua,
Cen Kefa
Publication year - 2017
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.201700733
Subject(s) - graphene , capacitance , materials science , capacitor , wetting , ion , chemical physics , substrate (aquarium) , nanotechnology , chemical engineering , composite material , chemistry , voltage , organic chemistry , physics , electrode , engineering , oceanography , quantum mechanics , geology
Abstract Graphene has been considered as a promising active material for electric double‐layer capacitors (EDLCs), primarily owing to its extraordinary monolayer properties, whereas the interfacial behaviors are conspicuously impacted by underlying substrates. In this work, substrate effects on the interfacial wettability, EDL structure, and capacitive behavior of graphene‐based EDLCs are delineated with numerical simulation. Unlike previous studies, a partial wetting transparency of topmost graphene is recognized for hydrophilic supports. In particular, a virtually identical capacitance is demonstrated for graphene with various supports, albeit the substantially different EDL structures stemmed from substrate effects. The achieved invariant capacitance is prominently attributed to the counterbalancing correlations between ions and proximal solvents, going beyond traditional views of modulating capacitance preferentially through ion structural evolutions. Specifically, the suppressed permittivity of apparently ordered water dipoles (i. e. detrimental solvent effects) attenuates the beneficial ionic influences (i. e. reinforced population and closer approach) on shielding the external electric fields. The as‐obtained findings demonstrate the paramount importance of the substrate in mediating interfacial behaviors within electrified EDLC systems and highlight that exploiting the pivotal interplay between ions and solvents could be a novel avenue to further manipulate electrochemical performances.