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Title: Correlating Humidity-Dependent Ionically Conductive Surface Area with Transport Phenomena in Proton-Exchange Membranes

Abstract

The objective of this effort was to correlate the local surface ionic conductance of a Nafion? 212 proton-exchange membrane with its bulk and interfacial transport properties as a function of water content. Both macroscopic and microscopic proton conductivities were investigated at different relative humidity levels, using electrochemical impedance spectroscopy and current-sensing atomic force microscopy (CSAFM). We were able to identify small ion-conducting domains that grew with humidity at the surface of the membrane. Numerical analysis of the surface ionic conductance images recorded at various relative humidity levels helped determine the fractional area of ion-conducting active sites. A simple square-root relationship between the fractional conducting area and observed interfacial mass-transport resistance was established. Furthermore, the relationship between the bulk ionic conductivity and surface ionic conductance pattern of the Nafion? membrane was examined.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1168741
Report Number(s):
LBNL-5441E
DOE Contract Number:  
DE-AC02-05CH11231
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry B
Additional Journal Information:
Journal Volume: 115; Journal Issue: 40
Country of Publication:
United States
Language:
English
Subject:
47 OTHER INSTRUMENTATION; 36 MATERIALS SCIENCE; Nafion, AFM, interfacial resistance, water transport, conductivity

Citation Formats

He, Qinggang, Kusoglu, Ahmet, Lucas, Ivan T., Clark, Kyle, Weber, Adam Z., and Kostecki, Robert. Correlating Humidity-Dependent Ionically Conductive Surface Area with Transport Phenomena in Proton-Exchange Membranes. United States: N. p., 2011. Web. doi:10.1021/jp206154y.
He, Qinggang, Kusoglu, Ahmet, Lucas, Ivan T., Clark, Kyle, Weber, Adam Z., & Kostecki, Robert. Correlating Humidity-Dependent Ionically Conductive Surface Area with Transport Phenomena in Proton-Exchange Membranes. United States. doi:10.1021/jp206154y.
He, Qinggang, Kusoglu, Ahmet, Lucas, Ivan T., Clark, Kyle, Weber, Adam Z., and Kostecki, Robert. Mon . "Correlating Humidity-Dependent Ionically Conductive Surface Area with Transport Phenomena in Proton-Exchange Membranes". United States. doi:10.1021/jp206154y. https://www.osti.gov/servlets/purl/1168741.
@article{osti_1168741,
title = {Correlating Humidity-Dependent Ionically Conductive Surface Area with Transport Phenomena in Proton-Exchange Membranes},
author = {He, Qinggang and Kusoglu, Ahmet and Lucas, Ivan T. and Clark, Kyle and Weber, Adam Z. and Kostecki, Robert},
abstractNote = {The objective of this effort was to correlate the local surface ionic conductance of a Nafion? 212 proton-exchange membrane with its bulk and interfacial transport properties as a function of water content. Both macroscopic and microscopic proton conductivities were investigated at different relative humidity levels, using electrochemical impedance spectroscopy and current-sensing atomic force microscopy (CSAFM). We were able to identify small ion-conducting domains that grew with humidity at the surface of the membrane. Numerical analysis of the surface ionic conductance images recorded at various relative humidity levels helped determine the fractional area of ion-conducting active sites. A simple square-root relationship between the fractional conducting area and observed interfacial mass-transport resistance was established. Furthermore, the relationship between the bulk ionic conductivity and surface ionic conductance pattern of the Nafion? membrane was examined.},
doi = {10.1021/jp206154y},
journal = {Journal of Physical Chemistry B},
number = 40,
volume = 115,
place = {United States},
year = {2011},
month = {8}
}