skip to main content

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

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:
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
Research Org:
Oak Ridge National Laboratory (ORNL); Center for Nanophase Materials Sciences; Center for Computational Sciences
Sponsoring Org:
SC USDOE - Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CAPACITANCE; CAPACITY; ELECTRODES; ENERGY STORAGE; MOLECULAR DYNAMICS METHOD; REMOVAL