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Atomic force microscopy on cross sections of fuel cell membranes, electrodes, and membrane electrode assemblies

Hiesgen, Renate and Morawietz, Tobias and Handl, Michael and Corasaniti, Martina and Friedrich, K. Andreas (2015) Atomic force microscopy on cross sections of fuel cell membranes, electrodes, and membrane electrode assemblies. Electrochimica Acta, 162, pp. 86-99. Elsevier. DOI: dx.doi.org/10.1016/j.electacta.2014.11.122 ISSN 0013-4686

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Official URL: http://www.elsevier.com/locate/electacta

Abstract

Using material-sensitive and conductive atomic force microscopy (AFM) on cross sections of perfluorinated and sulfonated membranes at low humidity, crystalline polymer lamellae were imaged and their thickness determined to approximately 6 nm. In the capacitive current, water-rich and waterpoor areas with different phase structures were investigated. The formation of a local electrochemical double layer within the water-rich ionically conductive areas at the contact of the AFM tip with the electrolyte enabled their visibility. The large water-filled ionically conductive areas include numerous ionic domains. Under equilibrium conditions, these areas are spherical (appearing circular in the images) and with distinct size distribution. Forcing a current through the membranes (current-induced activation) led to merging of the water-filled ionically conductive areas in the voltage direction and resulted in an anisotropic ionically conducting network with flat channels. The distribution of the current in the membrane and catalytic layers of a pristine membrane electrode assembly (MEA) was analyzed. From the adhesion force mappings, an inhomogeneous distribution of ionomer in the catalytic layer was detected. Cross currents between Pt/C particles through large ionomer particles within the catalytic layer were detected and the ionomer content across an electrode was evaluated.

Item URL in elib:https://elib.dlr.de/99163/
Document Type:Article
Title:Atomic force microscopy on cross sections of fuel cell membranes, electrodes, and membrane electrode assemblies
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Hiesgen, Renaterenate.hiesgen (at) hs-esslingen.deUNSPECIFIED
Morawietz, TobiasHochschule EsslingenUNSPECIFIED
Handl, MichaelHochschule EsslingenUNSPECIFIED
Corasaniti, MartinaSolvay Specialty PolymersUNSPECIFIED
Friedrich, K. Andreasandreas.friedrich (at) dlr.deUNSPECIFIED
Date:2015
Journal or Publication Title:Electrochimica Acta
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:162
DOI :dx.doi.org/10.1016/j.electacta.2014.11.122
Page Range:pp. 86-99
Publisher:Elsevier
ISSN:0013-4686
Status:Published
Keywords:AFM PFSA conductive ionic network fuel cell catalytic layer ionomer content
HGF - Research field:Energy
HGF - Program:Efficient Energy Conversion and Use (old)
HGF - Program Themes:Fuel Cells (old)
DLR - Research area:Energy
DLR - Program:E EV - Energy process technology
DLR - Research theme (Project):E - Electrochemical Processes (old)
Location: Stuttgart
Institutes and Institutions:Institute of Engineering Thermodynamics > Electrochemical Energy Technology
Deposited By: Friedrich, Prof.Dr. Kaspar Andreas
Deposited On:09 Dec 2015 13:51
Last Modified:06 Sep 2019 15:16

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