Electrophysical Properties of Solid Electrolytes

The main principle, determining the apphcation of solid electrolytes in gas sensors, is based on type of conductivity and on stability of the electrophysical properties at alteration parameters of the measuring environment. In one s turn, type (character) of conductivity depends on structural characteristics of the solid electrolyte, working temperature, and measuring partial pressure. 

Based on the Wagner method [16], the required character of conductivity can be achieved by the introduction of admixture into the basis oxide, which has a common anion with the basis oxide, and the cation has less valence. Type and quantity of the defects are stipulated by the admixture and its concentration. As a rule, the majority of well-known solid electrolytes with pure oxygen-ionic conductivity have a fluorite CaFj crystalUne structure [17]. 

Appearance of the electronic conductivity in oxide electrolytes is connected to the development of conductive electrons in the lattice of solid solution, forming as a result of the reduction of cations Me — + 0, where 0 is an electron. 

Moreover, a part of the anion is removed from the sohd oxide lattice (n type of conductivity). 

Appearance of the current carriers as electron holes is connected to the oxidation of cations, that is, with their loss of electrons Me — + , where is the hole. 

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