Title: Effect of the Electric Double Layer on the Activation Energy of Ion Transport in Conical Nanopores

Abstract

Measured apparent activation energies, $$E_A$$, of ion transport (K ⁺ and Cl ^–) in conical glass nanopores are reported as a function of applied voltage (-0.5 to 0.5 V), pore size (20–2000 nm), and electrolyte concentration (0.1–50 mM). $$E_A$$ values for transport within an electrically charged conical glass nanopore differ from the bulk values due to the voltage and temperature-dependent distribution of the ions within the double layer. Remarkably, nanopores that display ion current rectification also display a large decrease in $$E_A$$ under accumulation mode conditions (at applied negative voltages versus an external ground) and a large increase in $$E_A$$ under depletion mode conditions (at positive voltages). Finite element simulations based on the Poisson–Nernst–Planck model semiquantitatively predict the measured temperature-dependent conductivity and dependence of $$E_A$$ on applied voltage. The results highlight the relationships between the distribution of ions with the nanopore, ionic current, and $$E_A$$ and their dependencies on pore size, temperature, ion concentration, and applied voltage.

Authors:

Perera, Rukshan T. ^[1]; Johnson, Robert P. ^[1]; Edwards, Martin A. ^[1]; White, Henry S. ^[1]

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+ Show Author Affiliations

1. Univ. of Utah, Salt Lake City, UT (United States)

Publication Date:

2015-09-30

Research Org.:

Energy Frontier Research Centers (EFRC) (United States). Nanostructures for Electrical Energy Storage (NEES)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1386251

Grant/Contract Number:  

SC0001160

Resource Type:

Journal Article: Accepted Manuscript

Journal Name:

Journal of Physical Chemistry. C

Additional Journal Information:

Journal Volume: 119; Journal Issue: 43; Related Information: NEES partners with University of Maryland (lead); University of California, Irvine; University of Florida; Los Alamos National Laboratory; Sandia National Laboratories; Yale University; Journal ID: ISSN 1932-7447

Publisher:

American Chemical Society

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; bio-inspired; energy storage (including batteries and capacitors); defects; charge transport; synthesis (novel materials); synthesis (self-assembly); synthesis (scalable processing)