Improved dielectric breakdown strength and energy storage properties in Er2O3 modified Sr0.35Bi0.35K0.25TiO3

The development of lead-free dielectric ceramics with excellent energy storage properties has received extensive research attention. Herein, Er2O3 modified Sr0.35Bi0.35K0.25TiO3 (SBKT) composite ceramic is investigated. As 2 wt.% Er2O3 is added, a certain amount of insulating second phase with fewer regions of high local electric field (numerically simulated by COMSOL) is formed, giving rise to the increase in the dielectric breakdown strength (BDS) due to the increased electrical resistivity and band gap, the decreased average grain size and the decreased leakage current density. This optimal composition exhibits many excellent energy storage properties, such as high energy storage density of 2.59 J/cm(3), high recoverable energy storage density (W-rec) of 2.17 J/cm(3) with high efficiency (eta) of 83.9% at 245 kV/cm, superior stability of temperature (< 1% variation of W-rec and eta in -25 similar to 150 degrees C), frequency (similar to 1.6% variation of W-rec with similar to 3.6% variation of eta in 10 similar to 500 Hz) and cycling (almost no change of W-rec and. within 10(5) cycles), and high discharge energy density of 1.51 J/cm(3) with high power density of 39.6 MW/cm(3) at 200 kV/cm. In this work, we provide a novel strategy and understanding to design the advanced pulse energy storage ceramics.

Automated summary

The research showed that in Er2O3-doped composite ceramics, the formation of a certain amount of insulating second phase led to an increase in dielectric breakdown strength, as well as improvements in energy storage density, recoverable energy storage density, efficiency, and other excellent properties. The optimal composition also exhibited superior stability and high discharge energy density.