Reduced conductivity in sandwich-structured BFT@DA/PVDF flexible nanocomposites for high energy storage density in lower electric field

摘要

The Ba(Fe_(0.5)Ta_(0.5))O_(3)@DA/PVDF flexible composite films with sandwich-structured are prepared by solution-casting method. According to SEM image, the thickness of the composite film is about 15?μm and the each layer is about 5?μm. The sandwich-structured nanocomposite films not only have higher permittivity but also lower AC conductivity. The high permittivity is due to the large permittivity of BFT and the enhanced interface polarization between ceramic particles and polymer matrix. The low AC conductivity is due to the absence of conductive pathways in the PVDF layer. At low electric field strength of 150?MV/m, the energy density of sandwich-structure composite films filled with 1?vol% is 1.93?J/cm~(3). When the breakdown strength is 250?MV/m, the maximum energy storage density is increased to 4.87?J/cm~(3). The sandwich-structure Ba(Fe_(0.5)Ta_(0.5))O_(3)@DA/PVDF flexible composite films with outstanding energy storage properties in lower electric field can be used for wearable devices in the future.