Giant Permittivity in Polyvinylidene Fluoride Composites Filled with Flower-Like BaTiO3 for Energy Storage

This work reports giant permittivities over 10,000 in a polymer-matrix composite filled with the flowerlike BT fillers. At frequency of 10-100 Hz, polyvinylidene fluoride (PVDF) composites filled with BT flowers exhibit an extraordinary giant dielectric constant of ε_r ~ 16,200, while the value is 13 for the neat PVDF and 68 for the traditional composite filled with BT spheres. The giant dielectric constants may rise from the Maxwell-Wagner-Sillars polarization which is highly enhanced when BT fillers take the flower-like morphology. Furthermore, the composite shows the discharged energy storage density of U_d ~ 2,033 J cm^-3 at 200 MV m^-1. This work demonstrates the unprecedented high ε_r and U_d of a PVDF/BT composite and its strong potential in energy storage applications in a specific frequency region.