La10W22O81–SiO2 and La10W22O81–WO3 Composites: Morphology and Thermal and Electrical Transport Properties

Composites based on La10W22O81 with highly dispersed additives of the insulator SiO2 and the electronic conductor WO3 have been synthesized through a ceramic route. Their morphology, thermal properties, and electrical transport characteristics have been studied. X-ray diffraction confirmed the two-phase nature of the composites. Using EMF and the dependence of electrical conductivity on the partial pressure of oxygen, it has been established that, despite the different electrical properties of the dispersed additives, oxygen ions serve as charge carriers in the La10W22O81–WO3 and La10W22O81–SiO2 composites, and the electrical conductivity of the studied composites is more than tenfold higher than that of the La10W22O81 matrix. Based on an analysis of the morphology of the composites and the concentration dependences of their electrical conductivity, there have been proposed models of their structure that adequately explain the increase in ionic conductivity of the composites compared to the conductivity of the matrix.