Enhanced dielectric and energy storage density induced by surface-modified BaTiO3 nanofibers in poly(vinylidene fluoride) nanocomposites

A high energy-storage density ceramic-polymer nanocomposite is fabricated by incorporating high aspect ratio functionalized BaTiO3 nanofibers (BT NF) prepared via electrospinning into a polyvinylidene-fluoride (PVDF) matrix. The functionalized BT NF by 3-aminopropyltriethoxysilane (APS) not only exhibited excellent compatibility with poly(vinylidene fluoride) (PVDF), but significantly enhanced the dielectric properties of the nanocomposites. The dielectric constant of the nanocomposite reached up to 24 with a dielectric loss of 0.018 at 1 kHz with a BT NF-APS concentration of 7.5 vol%. The maximal energy-storage density in the nanocomposite with 2.5 vol% BT NF-APS is about 5.6 J/cm3 at 3300 kV/cm, which is over 220% higher than that of the PVDF at the same electric field. The enhanced energy-storage density could be attributed to the combined effects of the APS surface modification, large aspect ratio and ferroelectric polarization behavior of the BT NF.