High dielectric strength and energy storage density in Ba6−3xLn8+2xTi18O54 (Ln = La, Sm) low-loss dielectric ceramics

Abstract

Dielectric strength and energy storage density in Ba6−3x Ln8+2x Ti18O54 (Ln = La, Sm) low-loss dielectric ceramics have been investigated together with their composition and microstructure dependences. The dielectric strength increases with increasing x at first, reaches the maximum around x = 2/3 and turns to decrease for x = 3/4, except the composition x = 3/4 for Ba6−3x Sm8+2x Ti18O54, while the energy storage density decreases generally with increasing x. The maximum energy storage density is 0.38 J/cm3 under an electric field of 26 MV/m for x = 1/4 in Ba6−3x La8+2x Ti18O54. The highest dielectric strength and energy storage density are obtained in the present ceramics with the maximum bulk density and the minimum grain size. Compared with the ferroelectric materials, very low dielectric loss combined with the excellent temperature stability provide the essential advantages for the energy storage applications.