Ab initio molecular dynamics study of hydroxide diffusion mechanisms in nanoconfined structural mimics of anion exchange membranes

Tamar Zelovich, Zhuoran Long, Michael Anthony Hickner, Stephen J. Paddison, Chulsung Bae, Mark E. Tuckerman

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

The development of reliable, cost-effective polymer architectures for use as anion exchange membranes (AEMs) is an important challenge facing emerging electrochemical device technologies. Elucidation of key design principles underlying these electrolytes requires a fundamental understanding of the hydroxide ion transport mechanism in the aqueous region of an AEM. To this end, we have carried out a series of atomistic ab initio molecular dynamics calculations. To mimic the complex AEM nanoconfined environment, we employ graphane bilayers or carbon nanotubes to which selected cationic groups are attached and which are subsequently filled with water and hydroxide ions to achieve target water-to-cation ratios and overall electrical neutrality. The complex structure of water under nanoconfinement differs from the bulk and is controlled by the shape and size of the confining volume. Consequently, the local hydroxide ion diffusion mechanisms in different chemical and geometric environments is also seen to differ from that in bulk aqueous solution and depends on a number of design parameters, including hydration level, cation spacing, and cell geometry. An exploration of this large parameter space will be presented in a series of reports; in this first one, we introduce analysis tools to characterize the system, elucidate hydroxide transport mechanisms, and present our first set of case studies.

Original languageEnglish (US)
JournalJournal of Physical Chemistry C
DOIs
StatePublished - Jan 1 2019

Fingerprint

hydroxides
Anions
Molecular dynamics
Ion exchange
Negative ions
molecular dynamics
anions
membranes
Membranes
Ions
Positive ions
Cations
Water
water
cations
Hydration
ions
Carbon Nanotubes
Carbon nanotubes
Electrolytes

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

Cite this

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title = "Ab initio molecular dynamics study of hydroxide diffusion mechanisms in nanoconfined structural mimics of anion exchange membranes",
abstract = "The development of reliable, cost-effective polymer architectures for use as anion exchange membranes (AEMs) is an important challenge facing emerging electrochemical device technologies. Elucidation of key design principles underlying these electrolytes requires a fundamental understanding of the hydroxide ion transport mechanism in the aqueous region of an AEM. To this end, we have carried out a series of atomistic ab initio molecular dynamics calculations. To mimic the complex AEM nanoconfined environment, we employ graphane bilayers or carbon nanotubes to which selected cationic groups are attached and which are subsequently filled with water and hydroxide ions to achieve target water-to-cation ratios and overall electrical neutrality. The complex structure of water under nanoconfinement differs from the bulk and is controlled by the shape and size of the confining volume. Consequently, the local hydroxide ion diffusion mechanisms in different chemical and geometric environments is also seen to differ from that in bulk aqueous solution and depends on a number of design parameters, including hydration level, cation spacing, and cell geometry. An exploration of this large parameter space will be presented in a series of reports; in this first one, we introduce analysis tools to characterize the system, elucidate hydroxide transport mechanisms, and present our first set of case studies.",
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Ab initio molecular dynamics study of hydroxide diffusion mechanisms in nanoconfined structural mimics of anion exchange membranes. / Zelovich, Tamar; Long, Zhuoran; Hickner, Michael Anthony; Paddison, Stephen J.; Bae, Chulsung; Tuckerman, Mark E.

In: Journal of Physical Chemistry C, 01.01.2019.

Research output: Contribution to journalArticle

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AU - Long, Zhuoran

AU - Hickner, Michael Anthony

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AU - Bae, Chulsung

AU - Tuckerman, Mark E.

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