High-temperature energy storage properties in polyimide-based nanocomposites filled with antiferroelectric nanoparticles

Inorganic ferroelectric filler/polymer nanocomposites combining large maximum electric displacement (D_max) of ferroelectric materials with good flexibility and high electric breakdown strength (E_b) of the polymers are regarded as the most promising materials for preparing flexible dielectric capacitors with superior energy storage properties. Besides dielectric capacitors are always faced with high temperature environment in many application cases, and thus the applicability of high temperature is also highly desired. To develop nanocomposite-based dielectric capacitors with superior energy storage properties in a wide temperature range, in this study, we synthesize Pb_0.97La_0.02(Zr_0.5Sn_0.38Ti_0.12)O3 (PLZST) antiferroelectric nanoparticles (NPs) with larger D_max and smaller remnant electric displacement (D_r) in comparison with ferroelectric nanoparticles and disperse them into polyimide (PI) polymer matrix with good temperature stability. The results indicate that by adjusting reasonably the PLZST filler content, in a wide temperature range of 20-120 ^◦C, 7 wt.% PLZST/PI nanocomposite exhibits slim electric displacement-electric field hysteresis loops and low D_r, and thus the discharge energy density and energy efficiency are always higher than 4 J/cm³ and 90%, respectively. These indicate this nanocomposite is a good candidate material for developing flexible dielectric capacitors applicable in high temperature environment.