High energy density and high efficiency achieved in the Ca_(0.74)Sr_(0.26)Zr_(0.7)Ti_(0.3)O_3 linear dielectric thin films on the silicon substrates

摘要

Linear dielectrics are promising candidates for high-performance energy storage applications with high efficiency, excellent thermal stability, and high reliability due to their low loss, high dielectric breakdown strength, and stable dielectric properties, which are independent of the electric field and temperature. However, their low dielectric constant or polarization restricts the stored electrical energy, which makes them less attractive for high energy density storage applications compared to relaxor ferroelectrics or anti-ferroelectrics. Here, we realized an ultrahigh energy density (U_e ～ 59.4 J/cm~3) and high efficiency (～89%) simultaneously in the Ca_(0.74)Sr_(0.26)Zr_(0.7)Ti_(0.3)O_3 (CSZT) linear dielectric thin film, which are competitive with those of other lead-based and lead-free dielectric films deposited on Si wafers. Moreover, the CSZT thin-film capacitor exhibits great thermal stability with the U_e variation less than 3% from - 90 °C to 170 °C and good fatigue endurance with the U_e variation of 4.5% after 3×10~7 cycles at 10kHz. This work also reveals that the exploration of advanced linear dielectric thin films with a medium dielectric constant would benefit from the development of high-performance energy-storage capacitors.