Temperature dependence of anomalous protonic and superprotonic transport properties in mixed salts based on CsH2PO4

We present an experimental study and a theoretical interpretation of the temperature dependence of the transport properties of doped CsH2PO4 salts in both protonic and superprotonic phases. Cesium phosphate based solid electrolytes are technologically relevant because their operational temperature r...

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Bibliographic Details
Published in:Physical chemistry chemical physics : PCCP 2019, Vol.21 (24), p.12948-12960
Main Authors: Andrio, Andreu, Hernández, S I, García-Alcántara, C, del Castillo, L F, Compañ, Vicente, Santamaría-Holek, Iván
Format: Article
Language:English
Subjects:
Cesium
Current carriers
Dielectric properties
Electrode polarization
Electrolytes
Electrolytic cells
Fuel cells
Ions
Molten salt electrolytes
Morphology
Rubidium
Solid electrolytes
Temperature dependence
Transport properties
X ray spectrometers
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Summary:We present an experimental study and a theoretical interpretation of the temperature dependence of the transport properties of doped CsH2PO4 salts in both protonic and superprotonic phases. Cesium phosphate based solid electrolytes are technologically relevant because their operational temperature range is about 100 to 300 °C in which a superprotonic transition may manifest depending on its mixed composition. The experimental study was carried out using impedance spectroscopy at the temperature range of 150–230 °C, and the protonic and superprotonic transport properties and proton concentrations were calculated and analyzed by using the electrode polarization, and the Debye and Cole–Cole models for the dielectric constant. We have shown that the transport properties predicted by the Cole–Cole model are consistent with the conductivity measurements whereas the Debye model shows some inconsistencies. We attribute this to the fact that the Cole–Cole model incorporates the effects of interactions among charge carriers better than the more commonly used Debye model. In this way, our work shows a more consistent approach to determine the transport properties of solid electrolytes and, therefore, provides a more reliable tool to analyze the transport properties of heterogeneous solid electrolytes that can be used in electrochemical devices, including fuel cells and supercapacitors.
ISSN:1463-9076
1463-9084
DOI:10.1039/c8cp07472k