Voltage dependent charge storage modes and capacity in subnanometer pores

Peng Wu, Jingsong Huang, Vincent Meunier, Bobby G. Sumpter, Rui Qiao

Research output: Contribution to journalArticlepeer-review

76 Scopus citations

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.

Original languageEnglish
Pages (from-to)1732-1737
Number of pages6
JournalJournal of Physical Chemistry Letters
Volume3
Issue number13
DOIs
StatePublished - Jul 5 2012

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