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Title: Current rectification for transport of room-temperature ionic liquids through conical nanopores

Here, we studied the transport of room-temperature ionic liquids (RTILs) through charged conical nanopores using a Landau-Ginzburg-type continuum model that takes steric effect and strong ion-ion correlations into account. When the surface charge is uniform on the pore wall, weak current rectification is observed. When the charge density near the pore base is removed, the ionic current is greatly suppressed under negative bias voltage while nearly unchanged under positive bias voltage, thereby leading to enhanced current rectification. These predictions agree qualitatively with prior experimental observations, and we elucidated them by analyzing the different components of the ionic current and the structural changes of electrical double layers (EDLs) at the pore tip under different bias voltages and surface charge patterns. These analyses reveal that the different modifications of the EDL structure near the pore tip by the positive and negative bias voltages cause the current rectification and the observed dependence on the distribution of surface charge on the pore wall. The fact that the current rectification phenomena are captured qualitatively by the simple model originally developed for describing EDLs at equilibrium conditions suggests that this model may be promising for understanding the ionic transport under nonequilibrium conditions when the EDL structuremore » is strongly perturbed by external fields.« less
Authors:
 [1] ;  [2] ;  [2]
  1. Argonne National Lab. (ANL), Lemont, IL (United States)
  2. Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)
Publication Date:
Grant/Contract Number:
AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. C
Additional Journal Information:
Journal Volume: 120; Journal Issue: 8; Journal ID: ISSN 1932-7447
Publisher:
American Chemical Society
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22) Materials Sciences and Engineering Division; National Science Foundation (NSF)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1339300

Jiang, Xikai, Liu, Ying, and Qiao, Rui. Current rectification for transport of room-temperature ionic liquids through conical nanopores. United States: N. p., Web. doi:10.1021/acs.jpcc.5b11522.
Jiang, Xikai, Liu, Ying, & Qiao, Rui. Current rectification for transport of room-temperature ionic liquids through conical nanopores. United States. doi:10.1021/acs.jpcc.5b11522.
Jiang, Xikai, Liu, Ying, and Qiao, Rui. 2016. "Current rectification for transport of room-temperature ionic liquids through conical nanopores". United States. doi:10.1021/acs.jpcc.5b11522. https://www.osti.gov/servlets/purl/1339300.
@article{osti_1339300,
title = {Current rectification for transport of room-temperature ionic liquids through conical nanopores},
author = {Jiang, Xikai and Liu, Ying and Qiao, Rui},
abstractNote = {Here, we studied the transport of room-temperature ionic liquids (RTILs) through charged conical nanopores using a Landau-Ginzburg-type continuum model that takes steric effect and strong ion-ion correlations into account. When the surface charge is uniform on the pore wall, weak current rectification is observed. When the charge density near the pore base is removed, the ionic current is greatly suppressed under negative bias voltage while nearly unchanged under positive bias voltage, thereby leading to enhanced current rectification. These predictions agree qualitatively with prior experimental observations, and we elucidated them by analyzing the different components of the ionic current and the structural changes of electrical double layers (EDLs) at the pore tip under different bias voltages and surface charge patterns. These analyses reveal that the different modifications of the EDL structure near the pore tip by the positive and negative bias voltages cause the current rectification and the observed dependence on the distribution of surface charge on the pore wall. The fact that the current rectification phenomena are captured qualitatively by the simple model originally developed for describing EDLs at equilibrium conditions suggests that this model may be promising for understanding the ionic transport under nonequilibrium conditions when the EDL structure is strongly perturbed by external fields.},
doi = {10.1021/acs.jpcc.5b11522},
journal = {Journal of Physical Chemistry. C},
number = 8,
volume = 120,
place = {United States},
year = {2016},
month = {2}
}