High-energy density capacitors utilizing 0.7 baTiO₃-0.3 BiScO₃ ceramics

A high, temperature-stable dielectric constant (∼1000 from 0° to 300°C) coupled with a high electrical resistivity (∼10¹² Ω·cm at 250°C) make 0.7 BaTiO₃-0.3 BiScO₃ ceramics an attractive candidate for high-energy density capacitors operating at elevated temperatures. Single dielectric layer capacitors were prepared to confirm the feasibility of BaTiO₃-BiScO₃ for this application. It was found that an energy density of about 6.1 J/cm³ at a field of 73 kV/mm could be achieved at room temperature, which is superior to typical commercial X7R capacitors. Moreover, the high-energy density values were retained to 300°C. This suggests that BaTiO₃-BiScO ₃ ceramics have some advantages compared with conventional capacitor materials for high-temperature energy storage, and with further improvements in microstructure and composition, could provide realistic solutions for power electronic capacitors.