Electronic Percolation Threshold of Self-Standing Ag-LaCoO 3 Porous Electrodes for Practical Applications

Perovskite LaCoO 3 materials have various applications, from selective permeable membranes and gas sensing devices to water splitting applications. However, the intrinsic electrical resistivity of the perovskite limits the applicative potential. To overcome that, Ag powder was used with LaCoO 3 to o...

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Bibliographic Details
Published inMaterials Vol. 12; no. 15
Main Authors Enache, Stanica, Dragan, Mirela, Varlam, Mihai, Petrov, Konstantin
Format Journal Article
LanguageEnglish
Published Switzerland 25.07.2019
Subjects
perovskites
effective medium theory
sintering
composite media
electrical resistivity
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Summary:Perovskite LaCoO 3 materials have various applications, from selective permeable membranes and gas sensing devices to water splitting applications. However, the intrinsic electrical resistivity of the perovskite limits the applicative potential. To overcome that, Ag powder was used with LaCoO 3 to obtain porous composite electrodes with enhanced conductivities. For that, a series of composite Ag-LaCoO 3 powders were prepared into pellets and pre-sintered at various temperatures up to 1000 ∘ C. Their structural properties and morphology were investigated by X-ray diffraction and scanning electron microscopy. The electronic transport of compacted specimens was studied by impedance spectroscopy. The results indicate that the presence of Ag acts as pre-sintering additive to obtain porous electrodes, with porosity values as high as 40% at 50 vol. % Ag. Moreover, the overall electrical resistivity of the composite electrodes varied well over four orders of magnitude. The results are discussed within the generalized Bruggeman theory for effective media comprising arbitrarily shaped metallic and semiconducting inclusions.
ISSN:1996-1944
1996-1944