Search

Polymer dielectrics with excellent thermal stability are the essential core material for thin film capacitors applied in a harsh-environment. However, the dielectric and mechanical properties of polymers are commonly deteriorated with temperature rising. Herein, polyetherimide (PEI)-based nanocomposites contained with SiO

Polymer dielectrics with available energy storage performance at high temperatures are critical to meet the demands of emerging applications such as hybrid electric vehicles (HEVs), wind turbine generators, and oil and gas exploration. But the dielectric properties of most engineering polymers with thermotolerance rapidly deteriorate with temperature rising. Here, polyetherimide (PEI) nanocomposite films containing Al2O3 nanoparticles (AO-nps) were fabricated by a solution casting method. The dielectric properties, breakdown strength, and energy storage performances of PEI/AO-nps nanocomposites were investigated from 25 °C to 150 °C. With the introduction of AO-nps, the breakdown strength of the nanocomposites was greatly improved at high temperatures because AO-nps significantly inhibit the injected charges. The 1 vol% PEI/AO-nps nanocomposite exhibits excellent capacitive performance, e.g., a discharge energy density of 3.70 J cm−3 with a charge–discharge efficiency of 90.1% evaluated at 500 MV m−1 and 150 °C, which is the maximal value compared with the state-of-the-art counterparts. The high-temperature applicability of the present nanocomposite film makes it promising in manufacturing dielectric energy storage devices for harsh environments.

Polymer-based dielectric nanocomposites are excellent in developing dielectric energy storage devices, and the one-dimensional shape has been considered as a superior morphology for the ceramic nanofillers in dielectric nanocomposite. In the present work, a series of PbZr0.52Ti0.48O3 nanofibers (PZT-NF) were prepared via electrospinning. Three different diameter distributions of 500–600 nm, 300–400 nm and around 100 nm were obtained by adjusting the parameters in the electrospinning process, respectively. The nanocomposite films of PZT-NF/P(VDF-HFP) contained with different diameter nanofibers were prepared. The dielectric properties of the nanocomposites were comparatively investigated and the one with the thinnest nanofibers exhibits the best performances. The increasing dielectric permittivity with nanofiber diameter decrease is in accord with effective medium theory and the enhanced breakdown strength is well demonstrated by phase-field simulation. With larger dielectric displacement and breakdown strength, the nanocomposite loaded 3 vol% thinnest nanofibers represents maximal energy density of 12.58 J/cm3 at 470 kV/mm. The strategy of modulating nanofiber diameter in electrospinning has great potential in further enhancing energy density in dielectric nanocomposites.