Improved energy storage properties and stability of La modified 0.7Bi0.5Na0.5TiO3-0.3SrTiO3 ceramics

Abstract

The pursuit of lead-free ceramic capacitors with superior energy storage properties has garnered increasing attention. Herein, 0.7Bi0.5Na0.5TiO3-0.3SrTiO3-xLa (BNT-ST-xLa) ceramics were synthesized via citrate combustion technology. The results show that La doped BNT-ST induces dielectric relaxation behavior and promotes the formation of nanoscale domains, which has been confirmed by PFM and TEM, and slim hysteresis loops are realized as addition of La. The recoverable energy-storage density (Wre of 2.05 J/cm3) and efficiency (η of 82 %) are obtained in 4 mol% La doped ceramic under relatively low electric field of 170 kV/cm. The energy-storage performances of the ceramics show excellent frequency stability (Wre varies <1.9 % and η varies <3.1 % at 5 Hz–100 Hz) and thermal stability (Wre varies <1 % and η varies <6.1 % within 23 °C to 73 °C). It is revealed that the introduction of La results in the formation of nanodomains with currently improved energy storage properties.