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Title: On the hydrophilicity of electrodes for capacitive energy extraction

Journal Article · · Journal of Physics. Condensed Matter
 [1];  [1];  [2];  [1]
  1. Univ. of California, Riverside, CA (United States). Dept. of Chemical and Environmental Engineering. Dept. of Mathematics
  2. East China Univ. of Science and Technology, Shanghai (China). State Key Lab. of Chemical Engineering
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The so-called Capmix technique for energy extraction is based on the cyclic expansion of electrical double layers to harvest dissipative energy arising from the salinity difference between freshwater and seawater. Its optimal performance requires a careful selection of the electrical potentials for the charging and discharging processes, which must be matched with the pore characteristics of the electrode materials. While a number of recent studies have examined the effects of the electrode pore size and geometry on the capacitive energy extraction processes, there is little knowledge on how the surface properties of the electrodes affect the thermodynamic efficiency. In this paper, we investigate the Capmix processes using the classical density functional theory for a realistic model of electrolyte solutions. The theoretical predictions allow us to identify optimal operation parameters for capacitive energy extraction with porous electrodes of different surface hydrophobicity. Finally, in agreement with recent experiments, we find that the thermodynamic efficiency can be much improved by using most hydrophilic electrodes.

Research Organization:
Univ. of California, Riverside, CA (United States); East China Univ. of Science and Technology, Shanghai (China); Energy Frontier Research Centers (EFRC) (United States). Fluid Interface Reactions, Structures and Transport Center (FIRST)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES); Chinese Scholarship Council
Contributing Organization:
Tsinghua Univ., Beijing (China)
Grant/Contract Number:
AC05-00OR22725
OSTI ID:
1340470
Alternate ID(s):
OSTI ID: 1324475
Journal Information:
Journal of Physics. Condensed Matter, Vol. 28, Issue 46; ISSN 0953-8984
Publisher:
IOP PublishingCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 8 works
Citation information provided by
Web of Science

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Cited By (4)

Direct Electricity Generation Mediated by Molecular Interactions with Low Dimensional Carbon Materials—A Mechanistic Perspective journal October 2018
Time-dependent density functional theory for the charging kinetics of electric double layer containing room-temperature ionic liquids journal November 2016
Study of a water-graphene capacitor with molecular density functional theory journal September 2019
Computational Insights into Materials and Interfaces for Capacitive Energy Storage journal April 2017

Figures / Tables (5)

Figure 1(p. 17)figure Figure 1
Figure 2(p. 18)figure Figure 2
Figure 3(p. 19)figure Figure 3
Figure 4(p. 20)figure Figure 4
Figure 5(p. 21)figure Figure 5

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Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
energy extraction
salinity exchange
electric double layer
classical density functional theory