Enhanced energy density in polyetherimide nanocomposite film at high temperature induced by electrospun BaZrTiO 3 nanofibers

Polymer dielectrics which possess excellent dielectric properties such as high breakdown strength, flexibility, and facile processability are considered as promising materials for advanced electrostatic capacitors. However, most dielectric polymers have unsatisfactory energy storage performances at high-temperature environments. Here, polyetherimide (PEI) nanocomposite films contained with electrospun Ba(Zr 0.79 Ti 0.21 )O 3 nanofibers (BZTNFs) are fabricated by common solution casting method. The dielectric properties, especially the breakdown strength of the BZTNFs/PEI nanocomposites, are characterized, yet improvement is only in the small loading ones. The energy storage performance of the 0.5 vol% and 1.0 vol% BZTNFs content nanocomposite is further investigated from 25 to 150 °C. With the introduction of small loading BZTNFs, the dielectric permittivity and electric displacement of the nanocomposite are improved at all evaluated temperatures. The 1.0 vol% BZTNFs/PEI possesses a maximal discharged energy density of 6.05 J·cm −3 with high efficiency of 94.9% at 25 °C, then falls to 3.34 J·cm −3 with efficiency of 54.6% at 150 °C for the larger remnant displacement. Apparently, the relaxation ferroelectric nanofiller of BZTNFs is much effective in increasing the dielectric permittivity of nanocomposite, but its capacity to restrict the migration of the charge carriers at high temperatures is weaker than that of the nanofillers with wider bandgap. The complementation of both kinds of the nanofillers probably provides an approach to available high-temperature dielectric films. Graphical abstract