Three-dimensional pore structure and ion conductivity of porous ceramic diaphragms

Wiedenmann, Daniel; Keller, Lukas; Holzer, Lorenz; Stojadinović, Jelena; Münch, Beat; Suarez, Laura; Fumey, Benjamin; Hagendorfer, Harald; Brönnimann, Rolf; Modregger, Peter; Gorbar, Michal; Vogt, Ulrich F.; Züttel, Andreas; Mantia, Fabio La; Wepf, Roger; Grobéty, Bernard

doi:10.1002/aic.14094

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Journal article

Three-dimensional pore structure and ion conductivity of porous ceramic diaphragms

Wiedenmann, Daniel Dept. of Geosciences and FRIMAT, University of Fribourg, Switzerland
Keller, Lukas EMPA, Swiss Federal Laboratories for Materials Testing and Research, Dübendorf, Switzerland
Holzer, Lorenz ZHAW, Institute of Computational Physics ICP, Zurich University of Applied Sciences, Winterthur, Switzerland
Stojadinović, Jelena EMPA, Swiss Federal Laboratories for Materials Testing and Research, Dübendorf, Switzerland
Münch, Beat EMPA, Swiss Federal Laboratories for Materials Testing and Research, Dübendorf, Switzerland
Suarez, Laura EMPA, Swiss Federal Laboratories for Materials Testing and Research, Dübendorf, Switzerland
Fumey, Benjamin EMPA, Swiss Federal Laboratories for Materials Testing and Research, Dübendorf, Switzerland
Hagendorfer, Harald EMPA, Swiss Federal Laboratories for Materials Testing and Research, Dübendorf, Switzerland
Brönnimann, Rolf EMPA, Swiss Federal Laboratories for Materials Testing and Research, Dübendorf, Switzerland
Modregger, Peter Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland - School of Biology and Medicine, University of Lausanne, Switzerland
Gorbar, Michal EMPA, Swiss Federal Laboratories for Materials Testing and Research, Dübendorf, Switzerland
Vogt, Ulrich F. EMPA, Swiss Federal Laboratories for Materials Testing and Research, Dübendorf, Switzerland
Züttel, Andreas EMPA, Swiss Federal Laboratories for Materials Testing and Research, Dübendorf, Switzerland
Mantia, Fabio La CES, Center for Electrochemical Sciences, Ruhr-University Bochum, Germany
Wepf, Roger ETH, Centre EMEZ, Zurich, Switzerland
Grobéty, Bernard Dept. of Geosciences and FRIMAT, University of Fribourg, Switzerland

2013

Published in:

AIChE Journal. - 2013, vol. 59, no. 5, p. 1446–1457

English The ion conductivity of two series of porous ceramic diaphragms impregnated with caustic potash was investigated by electrochemical impedance spectroscopy. To understand the impact of the pore structure on ion conductivity, the three-dimensional (3-D) pore geometry of the diaphragms was characterized with synchrotron x-ray absorption tomography. Ion migration was calculated based on an extended pore structure model, which includes the electrolyte conductivity and geometric pore parameters, for example, tortuosity (τ) and constriction factor (β), but no fitting parameters. The calculated ion conductivities are in agreement with the data obtained from electrochemical measurements on the diaphragms. The geometric tortuosity was found to be nearly independent of porosity. Pore path constrictions diminish with increasing porosity. The lower constrictivity provides more pore space that can effectively be used for mass transport. Direct measurements from tomographs of tortuosity and constrictivity opens new possibilities to study pore structures and transport properties of porous materials.

Faculty

Faculté des sciences et de médecine

Department

Département de Géosciences

Language