Simultaneously optimizing both energy storage density and efficiency in a novel lead-free relaxor antiferroelectrics

Abstract

Dielectric capacitors with both high energy density and efficiency are highly demanded in pulsed power systems. Relaxor antiferroelectrics have attracted much attention due to their unique advantages in optimizing both properties of a dielectric capacitor. In this work, a novel relaxor antiferroelectric ceramic with composition of (1-x)Bi0.5Na0.5TiO3-xAg0.91Sm0.03NbO3 was developed, where the antiferroelectricity was stabilized with the increase of Ag0.91Sm0.03NbO3 counterpart. Moreover, the relaxor feature was also obviously improved, as a result of chemical and structural disorder introduced by hetero cations with different radii and valence states. As expected, a high recoverable energy density of 2.1 J/cm3 accompanied with efficiency of 83 % was simultaneously achieved at x = 0.15. The as-prepared ceramics also exhibited good thermal stability in energy storage performance with small variations (energy storage density <10 % and efficiency <5 %) over 30−130 °C. All these merits demonstrate that the 0.85Bi0.5Na0.5TiO3-0.15Ag0.91Sm0.03NbO3 ceramic has great potential for high power energy storage applications.