Enhanced energy-storage performance and temperature-stable dielectric properties of (1-x)[(Na_0.5Bi_0.5)_0.95Ba_0.05]_0.98La_0.02TiO₃-xK_0.5Na_0.5NbO₃ lead-free ceramics

Polycrystalline (1-x)[(Na_0.5Bi_0.5)_0.95Ba_0.05]_0.98La_0.02TiO₃-xK_0.5Na_0.5NbO₃ systems were prepared using the solid-state reaction technique. Modification of (Na_0.5Bi_0.5)_0.95Ba_0.05]_0.98La_0.02TiO₃ ceramic with a proper amount of K_0.5Na_0.5NbO₃ can effectively improve the temperature-stable of dielectric properties. A variation in dielectric constant is maintained smaller than ±5% from 80 to 300 °C accompanied with a low dielectric loss (≤0.04). The relaxor properties of the doped samples are significantly enhanced. A high energy storage density of 1.1 J/cm³ and efficiency ~80% at 90 kV/cm are achieved in the x = 0.05 composition. Hence, the as-prepared ceramics might be practical in dielectric constant which can work stably at a high temperature range and pulsed capacitors.