Optimizing electrical performance of low hysteresis Sr0.7Bi0.2TiO3 energy storage ceramic

Abstract

Dielectric capacitors with rapid discharge rates and high power density are the basis for advanced pulsed power systems. Sr0.7Bi0.2TiO3 (SBT) is expected to be used in energy storage capacitors owing to the small hysteresis and high energy storage efficiency (η). Nevertheless, the low breakdown strength (BDS) limits the enhancement of energy storage density. This study explores the potential of Ho2O3-modified SBT to address this limitation. Introducing Ho reduces oxygen vacancies, decreases electrical conductivity, and increases thermal conductivity, thus enhancing BDS. The enhancement mechanism of electrical performance is studied through microscopic morphology analysis, structural refinement and numerical simulation. The Sr0.7Bi0.15Ho0.05TiO3 exhibits remarkable properties, including ultra-low loss tanδ (0.1 %), ultra-high η (95.8 %), and outstanding thermal, frequency, and cycling stability in energy storage properties. Additionally, Sr0.7Bi0.15Ho0.05TiO3 possesses a high power density (67.9 MW/cm3) and a rapid discharge rate (0.03 μs). The findings indicate that Sr0.7Bi0.15Ho0.05TiO3 is a prospective material for energy storage capacitors.