Enhanced breakdown strength and relevant mechanism of 0-3 type Sr0.7Bi0.2TiO3: Al2O3 composite ceramic with remarkable energy storage performances

In this work, a novel 0-3 type Sr0.7Bi0.2TiO3: Al2O3 composite ceramic is designed for dielectric capacitor applications. A superior energy density of 5.96J/cm3, a high current density of 1099A/cm² and a remarkable power density of 198MW/cm³ are concurrently achieved in the ceramic specimen due to the great enhancement of the breakdown strength. The microstructure and physical property characterization confirm that highly insulating Al2O3 particles existed in the ceramic matrix. It is evident that reduced grain sizes, the enhanced band gap energy and the increased activation energy contribute to the improvement of the breakdown strength. Ulteriorly, numerical simulations reveal that the primary factor might be ascribed to the decreased grain size. These findings demonstrate that the 0-3 type Sr0.7Bi0.2TiO3: Al2O3 composite ceramic is a promising candidate for energy storage applications.