Enhanced dielectric property and energy density of polydopamine encapsuled BaTiO3 nanofibers/PVDF nanocomposites

Ceramic-polymer nanocomposites with high dielectric constant and energy density are becoming increasingly attractive in modern electronic and electric industry. However, the breakdown strength of composites was usually largely reduced due to the unstable interfacial interaction between ceramic filler and polymer matrix. In this study, the flexible nanocomposites comprising dopamine encapsulated BaTiO₃ nanofibers (BTnfs) with a large aspect ratio prepared via electrospinning as fillers and poly(vinylidene fluoride) (PVDF) as matrix were fabricated by a solution casting method. The obtained nanocomposites displayed desirable dielectric properties and storage energy density with their loss tangents suppressed at low values. The energy density of the nanocomposites was significantly enhanced, and the maximal energy density of 0.0035 J/cm³ was obtained in the composite material containing 10 vol% modified BTnfs, which is more than doubled as compared with the pure PVDF. Our strategy provides a simple and effective way to prepare high performance flexible dielectric composite capacitors with high storage density.