Composite solid electrolytes MWO<sub>4</sub>–SiO<sub>2</sub> (M = Ca, Sr) and Ln<sub>2</sub>W<sub>3</sub>O<sub>12</su

Composite solid electrolytes based on alkaline earth tungstates MWO4–SiO2 (M = Ca, Sr) and rare earth metals Ln2W3O12–SiO2 (Ln = La, Nd) with the addition of nanodispersed silicon oxide were synthesized and their morphology, thermal, structural and electrical transport properties were studied. The absence of thermal effects on DSC of tungstates and silica mixtures as well as the absence of reflections of any foreign phases in the diffraction patterns of the composites, confirms their thermodynamic stability. The ionic nature of the composite conductivity is confirmed by the high values of ionic transfer numbers about 0.8–0.9 (EMF method) and the horizontal plot of conductivity versus oxygen pressure in the gas phase. The concentration dependence of the conductivity of the composites (1–x)MeWO4–xSiO2 (M = Ca, Sr), (1–x)Ln2W3O12–xSiO2 (Ln = La, Nd) passes through a maximum at x = 0.03–0.30 (x – mole fraction). The 0.70Nd2W3O12–0.30SiO2 composite has the best conductivity of 3.2 × 10−2 S/cm at 900°C.