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Title: Can ionophobic nanopores enhance the energy storage capacity of electric-double-layer capacitors containing nonaqueous electrolytes?

Abstract

The ionophobicity effect of nanoporous electrodes on the capacitance and the energy storage capacity of nonaqueous-electrolyte supercapacitors is studied by means of the classical density functional theory (DFT). It has been hypothesized that ionophobic nanopores may create obstacles in charging, but they store energy much more efficiently than ionophilic pores. In this paper, we find that, for both ionic liquids and organic electrolytes, an ionophobic pore exhibits a charging behavior different from that of an ionophilic pore, and that the capacitance–voltage curve changes from a bell shape to a two-hump camel shape when the pore ionophobicity increases. For electric-double-layer capacitors containing organic electrolytes, an increase in the ionophobicity of the nanopores leads to a higher capacity for energy storage. Without taking into account the effects of background screening, the DFT predicts that an ionophobic pore containing an ionic liquid does not enhance the supercapacitor performance within the practical voltage ranges. However, by using an effective dielectric constant to account for ion polarizability, the DFT predicts that, like an organic electrolyte, an ionophobic pore with an ionic liquid is also able to increase the energy stored when the electrode voltage is beyond a certain value. We find that the critical voltagemore » for an enhanced capacitance in an ionic liquid is larger than that in an organic electrolyte. Finally, our theoretical predictions provide further understanding of how chemical modification of porous electrodes affects the performance of supercapacitors.« less

Authors:
 [1];  [2];  [1];  [3];  [4]
  1. East China Univ. of Science and Technology, Shanghai (China). State Key Lab. of Chemical Engineering
  2. (United States). Dept. of Chemical and Environmental Engineering
  3. Brigham Young Univ., Provo, UT (United States). Dept. of Chemistry and Biochemistry
  4. Univ. of California, Riverside, CA (United States). Dept. of Chemical and Environmental Engineering
Publication Date:
Research Org.:
Brigham Young Univ., Provo, UT (United States); Univ. of California, Riverside, CA (United States); East China Univ. of Science and Technology, Shanghai (China)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); Chinese Scholarship Council; National Natural Science Foundation of China (NNSFC)
OSTI Identifier:
1340472
Grant/Contract Number:
AC05-00OR22725; 91334203; B08021
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Physics. Condensed Matter
Additional Journal Information:
Journal Volume: 28; Journal Issue: 41; Journal ID: ISSN 0953-8984
Publisher:
IOP Publishing
Country of Publication:
United States
Language:
English
Subject:
25 ENERGY STORAGE; energy storage; nonaqueous electrolytes; ionophobic nanopore; electrical double layer; classical density functional theory

Citation Formats

Lian, Cheng, Univ. of California, Riverside, CA, Liu, Honglai, Henderson, Douglas, and Wu, Jianzhong. Can ionophobic nanopores enhance the energy storage capacity of electric-double-layer capacitors containing nonaqueous electrolytes?. United States: N. p., 2016. Web. doi:10.1088/0953-8984/28/41/414005.
Lian, Cheng, Univ. of California, Riverside, CA, Liu, Honglai, Henderson, Douglas, & Wu, Jianzhong. Can ionophobic nanopores enhance the energy storage capacity of electric-double-layer capacitors containing nonaqueous electrolytes?. United States. doi:10.1088/0953-8984/28/41/414005.
Lian, Cheng, Univ. of California, Riverside, CA, Liu, Honglai, Henderson, Douglas, and Wu, Jianzhong. Mon . "Can ionophobic nanopores enhance the energy storage capacity of electric-double-layer capacitors containing nonaqueous electrolytes?". United States. doi:10.1088/0953-8984/28/41/414005. https://www.osti.gov/servlets/purl/1340472.
@article{osti_1340472,
title = {Can ionophobic nanopores enhance the energy storage capacity of electric-double-layer capacitors containing nonaqueous electrolytes?},
author = {Lian, Cheng and Univ. of California, Riverside, CA and Liu, Honglai and Henderson, Douglas and Wu, Jianzhong},
abstractNote = {The ionophobicity effect of nanoporous electrodes on the capacitance and the energy storage capacity of nonaqueous-electrolyte supercapacitors is studied by means of the classical density functional theory (DFT). It has been hypothesized that ionophobic nanopores may create obstacles in charging, but they store energy much more efficiently than ionophilic pores. In this paper, we find that, for both ionic liquids and organic electrolytes, an ionophobic pore exhibits a charging behavior different from that of an ionophilic pore, and that the capacitance–voltage curve changes from a bell shape to a two-hump camel shape when the pore ionophobicity increases. For electric-double-layer capacitors containing organic electrolytes, an increase in the ionophobicity of the nanopores leads to a higher capacity for energy storage. Without taking into account the effects of background screening, the DFT predicts that an ionophobic pore containing an ionic liquid does not enhance the supercapacitor performance within the practical voltage ranges. However, by using an effective dielectric constant to account for ion polarizability, the DFT predicts that, like an organic electrolyte, an ionophobic pore with an ionic liquid is also able to increase the energy stored when the electrode voltage is beyond a certain value. We find that the critical voltage for an enhanced capacitance in an ionic liquid is larger than that in an organic electrolyte. Finally, our theoretical predictions provide further understanding of how chemical modification of porous electrodes affects the performance of supercapacitors.},
doi = {10.1088/0953-8984/28/41/414005},
journal = {Journal of Physics. Condensed Matter},
number = 41,
volume = 28,
place = {United States},
year = {Mon Aug 22 00:00:00 EDT 2016},
month = {Mon Aug 22 00:00:00 EDT 2016}
}

Journal Article:
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