Temperature-stable Na0.5Bi0.5TiO3-based relaxor ceramics with high permittivity and large energy density under low electric fields

Abstract

Nowadays, it remains a challenge to achieve a simultaneous improvement of dielectric constant, energy density, and temperature stability in dielectric ceramics. In this work, it was found that such drawback could be effectively resolved by using KTaO3 to substitute Na0.5Bi0.5TiO3. In (1-x)Na0.5Bi0.5TiO3-xKTaO3 ceramics, the temperature coefficient of capacitance (TCC) of x = 0.10 composition is lower than 15% in the temperature range of 25–390 °C, with a high dielectric constant of 2008 and a low dielectric loss of 0.0044 at 150 °C. Meanwhile, a large discharged energy density of ~2.50 J/cm3 with the variation less than± 3% in 5–190 °C was obtained under a low electric field of 18 kV/mm in x = 0.20 composition, accompanied with a high energy efficiency of> 80%. These results reveal that this ceramic system is a promising candidate for temperature-stable dielectric and energy storage capacitors applications.