Ionic conductivity of ceramics prepared by sintering of M2O–Ln2O3–2SiO2 mixtures (M = Li, Na, K, Rb, Cs; Ln = La, Nd, Sm, Gd, Dy, Y, Ho, Er, Yb)

Abstract

Ionic conductivities have been measured over a wide range of temperature and frequency for ceramics prepared from M₂O–Ln₂O₃–2SiO₂ mixtures. In the samarium series, the activation energy and conductivity at 500 °C were estimated to be 78.4 kJ mol^–1 and 4.9 × 10^–4 S cm^–1 for Li, 69 kJ mol^–1 and 1.1 × 10^–4 S cm^–1 for Na, 18 kJ mol^–1 and 1.2 × 10^–2 S cm^–1 for K, 33 kJ mol^–1 and 3.99 × 10^–3 S cm^–1 for Rb, and 66 kJ mol^–1 and 3.8 × 10^–6 S cm^–1 for Cs. The values of the a and c parameters in the hexagonal phase of K₂O– and Rb₂O–Ln₂O₃–2SiO₂ are greater than the interpolated values for the Li and Cs series of hexagonal phase. The highest conductivity is achieved for K₂O–Nd₂O₃–2SiO₂ in a series of M₂O–Ln₂O₃–2SiO₂.