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

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 KTaO 3 to substitute Na 0.5 Bi 0.5 TiO 3 . In (1- x )Na 0.5 Bi 0.5 TiO 3 - x KTaO 3 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/cm 3 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.