Polyimide/zirconia nanoclusters dielectric composites with superior high-temperature energy storage performance

High-temperature polymer dielectrics are extremely critical for modern electronic and electrical systems. Unfortunately, the energy storage performance of dielectric polymers is dramatically deteriorated due to carrier injection and transport at elevated temperatures. In this paper, polyimide/zirconia nanoclusters dielectric composites are designed using a “site isolation” co -polymerization method. Based on the quantum size effect, ultrasmall zirconia nanoclusters (ZOCs) have a wider bandgap compared to conventional-sized zirconia nanoparticles (ZrO 2 NPs), which can increase the depth of carrier traps in dielectric composites to inhibit carrier transport better. The resulting composites exhibit superior high-temperature energy storage performance, including the maximum discharged energy density of 5.45 J/cm 3 and the charge-discharge efficiency of 87.5 % under 600 MV/m at 150 °C. This work offers a promising avenue to design high-temperature polymer dielectrics for energy storage applications.