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Title: Quantum Effects on the Capacitance of Graphene-Based Electrodes

Abstract

We recently measured quantum capacitance for electric double layers (EDL) at electrolyte/graphene interfaces. However, the importance of quantum capacitance in realistic carbon electrodes is not clear. Toward understanding that from a theoretical perspective, here we studied the quantum capacitance and total capacitance of graphene electrodes as a function of the number of graphene layers. The quantum capacitance was obtained from electronic density functional theory based on fixed band approximation with an implicit solvation model, while the EDL capacitances were from classical density functional theory. We found that quantum capacitance plays a dominant role in total capacitance of the single-layer graphene both in aqueous and ionic-liquid electrolytes but the contribution decreases as the number of graphene layers increases. Moreover, the total integral capacitance roughly levels off and is dominated by the EDL capacitance beyond about four graphene layers. Finally, because many porous carbons have nanopores with stacked graphene layers at the surface, this research provides a good estimate of the effect of quantum capacitance on their electrochemical performance.

Authors:
 [1];  [1];  [1];  [1]
  1. Univ. of California, Riverside, CA (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1265780
Grant/Contract Number:  
AC05-00OR22725
Resource Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. C
Additional Journal Information:
Journal Volume: 119; Journal Issue: 39; Journal ID: ISSN 1932-7447
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Zhan, Cheng, Neal, Justin, Wu, Jianzhong, and Jiang, De-en. Quantum Effects on the Capacitance of Graphene-Based Electrodes. United States: N. p., 2015. Web. doi:10.1021/acs.jpcc.5b05930.
Zhan, Cheng, Neal, Justin, Wu, Jianzhong, & Jiang, De-en. Quantum Effects on the Capacitance of Graphene-Based Electrodes. United States. doi:10.1021/acs.jpcc.5b05930.
Zhan, Cheng, Neal, Justin, Wu, Jianzhong, and Jiang, De-en. Tue . "Quantum Effects on the Capacitance of Graphene-Based Electrodes". United States. doi:10.1021/acs.jpcc.5b05930. https://www.osti.gov/servlets/purl/1265780.
@article{osti_1265780,
title = {Quantum Effects on the Capacitance of Graphene-Based Electrodes},
author = {Zhan, Cheng and Neal, Justin and Wu, Jianzhong and Jiang, De-en},
abstractNote = {We recently measured quantum capacitance for electric double layers (EDL) at electrolyte/graphene interfaces. However, the importance of quantum capacitance in realistic carbon electrodes is not clear. Toward understanding that from a theoretical perspective, here we studied the quantum capacitance and total capacitance of graphene electrodes as a function of the number of graphene layers. The quantum capacitance was obtained from electronic density functional theory based on fixed band approximation with an implicit solvation model, while the EDL capacitances were from classical density functional theory. We found that quantum capacitance plays a dominant role in total capacitance of the single-layer graphene both in aqueous and ionic-liquid electrolytes but the contribution decreases as the number of graphene layers increases. Moreover, the total integral capacitance roughly levels off and is dominated by the EDL capacitance beyond about four graphene layers. Finally, because many porous carbons have nanopores with stacked graphene layers at the surface, this research provides a good estimate of the effect of quantum capacitance on their electrochemical performance.},
doi = {10.1021/acs.jpcc.5b05930},
journal = {Journal of Physical Chemistry. C},
number = 39,
volume = 119,
place = {United States},
year = {2015},
month = {9}
}

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Cited by: 24 works
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