Electron Model of Solid Oxygen‐Ionic Electrolytes Used in Gas Sensors

Abstract

Yttria‐stabilized zirconia (YSZ)‐based ceramic gas sensors operating at high temperatures have been well established in many applications over the last 30 years. This article aims to provide an electron model of the solid electrolytes with oxygen‐ionic conductivity used in gas sensors to simulate contact phenomena on the boundary of a YSZ/metal electrode interface within the solid‐state zone theory. The primary focus of this article is modelling and assessment of the ability of a YSZ‐based electrolyte to control oxygen potentials at low temperatures in different environments. The proposed model allows the necessary information with regard to the electrolyte/metal electrode interface and about the character of the electronic conductivity to be obtained. The model also describes that the character of the electronic conductivity in solid electrolytes usually depends on two mechanisms of charge transfer: electrons transfer in the conductivity zone, separated from the valent zone in the solid electrolyte by the wide enough forbidden zone, and the spasmodic transitions of electrons from one local level to another within the forbidden zone.