Enhanced Dielectric and Energy Storage Properties of the (200)-oriented Plate-like Na0.5Bi0.5TiO3/Polyimide Composite Materials

Ferroelectric/polymer composites capable of possessing high dielectric constant, excellent flexibility and withstanding high electric field have been considered as promising candidates for embedded capacitor applications, or other energy storage/transfer devices. However, conventional ferroelectric particle composites only exhibit high dielectric enhancement at a high fraction, and cannot withstand high breakdown electric fields. Compared with particle fillers, the plate-like ferroelectrics with obvious anisotropic dielectric behaviors exhibit excellent dielectric properties in a co-plane orientation. Here we reported a new polyimide based composite material with the (200) oriented plate-like Na 0.5 Bi 0.5 TiO 3 powders as fillers. The results showed that the plate-like Na 0.5 Bi 0.5 TiO 3 fillers lead to a obviously increase of dielectric constant for polyimide composites (ε r =14.00) at a very low content when Na 0.5 Bi 0.5 TiO 3 content is about 5 wt%, which is 4.03 times as large as that of pure polyimide (ε r =3.47) while maintaining a relatively low loss (tgδ=0.0061) and high breakdown strength (1412 kV/cm). The measured energy density with 5 wt% Na 0.5 Bi 0.5 TiO 3 content increased to a value of 1.24 J/cm 3 , higher than that of pure polyimide (0.67 J/cm 3 ). The result indicates that the composite could have potential applications in embedded capacitors and microelectronic applications.