An electrolyte is a material in which an ion is the majority charge carrier. Solid electrolytes, also known as fast ion conductors and superionic conductors, are generally crystalline ceramic compounds. At elevated temperatures they allow ionic transport through vacancies or interstitials in the lattice.  These materials have found applications in electrolyzers, batteries, solid oxide fuel cells, and sensors.


A Nernstian solid electrolyte sensor consists of a gas impervious solid electrolyte, separating reference and measurement gas compartments. The electrolyte is coated with catalytically active electrodes, usually a noble metal such as platinum. The voltage generated between the sensor electrodes is determined by the gas partial pressures at the measurement and reference electrodes according to the Nernst equation:

Provided the partial pressure of gas at the reference electrode is known, the partial pressure of the measurement gas may be calculated directly from the sensor voltage.




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