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Title: Voltage Dependent Charge Storage Modes and Capacity in Subnanometer Pores

Abstract

Using molecular dynamics simulations, we show that charge storage in subnanometer pores follows a distinct voltage-dependent behavior. Specifically, at lower voltages, charge storage is achieved by swapping co-ions in the pore with counterions in the bulk electrolyte. As voltage increases, further charge storage is due mainly to the removal of co-ions from the pore, leading to a capacitance increase. The capacitance eventually reaches a maximum when all co-ions are expelled from the pore. At even higher electrode voltages, additional charge storage is realized by counterion insertion into the pore, accompanied by a reduction of capacitance. The molecular mechanisms of these observations are elucidated and provide useful insight for optimizing energy storage based on supercapacitors.

Authors:
 [1];  [2];  [3];  [3];  [3]
  1. Clemson University
  2. Rensselaer Polytechnic Institute (RPI)
  3. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Center for Nanophase Materials Sciences; Center for Computational Sciences
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1043333
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Physical Chemistry Letters; Journal Volume: 3; Journal Issue: 13
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CAPACITANCE; CAPACITY; ELECTRODES; ENERGY STORAGE; MOLECULAR DYNAMICS METHOD; REMOVAL

Citation Formats

Qiao, Rui, Meunier, V., Huang, Jingsong, Wu, Peng, and Sumpter, Bobby G. Voltage Dependent Charge Storage Modes and Capacity in Subnanometer Pores. United States: N. p., 2012. Web.
Qiao, Rui, Meunier, V., Huang, Jingsong, Wu, Peng, & Sumpter, Bobby G. Voltage Dependent Charge Storage Modes and Capacity in Subnanometer Pores. United States.
Qiao, Rui, Meunier, V., Huang, Jingsong, Wu, Peng, and Sumpter, Bobby G. 2012. "Voltage Dependent Charge Storage Modes and Capacity in Subnanometer Pores". United States. doi:.
@article{osti_1043333,
title = {Voltage Dependent Charge Storage Modes and Capacity in Subnanometer Pores},
author = {Qiao, Rui and Meunier, V. and Huang, Jingsong and Wu, Peng and Sumpter, Bobby G},
abstractNote = {Using molecular dynamics simulations, we show that charge storage in subnanometer pores follows a distinct voltage-dependent behavior. Specifically, at lower voltages, charge storage is achieved by swapping co-ions in the pore with counterions in the bulk electrolyte. As voltage increases, further charge storage is due mainly to the removal of co-ions from the pore, leading to a capacitance increase. The capacitance eventually reaches a maximum when all co-ions are expelled from the pore. At even higher electrode voltages, additional charge storage is realized by counterion insertion into the pore, accompanied by a reduction of capacitance. The molecular mechanisms of these observations are elucidated and provide useful insight for optimizing energy storage based on supercapacitors.},
doi = {},
journal = {Journal of Physical Chemistry Letters},
number = 13,
volume = 3,
place = {United States},
year = 2012,
month = 1
}
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