Effect of BaTiO3 nanowires on dielectric properties and energy storage density of polyimide composite films

BaTiO 3 nanowires/polyimide (BT-NWs/PI) and BaTiO 3 nanoparticles/polyimide (BT-NPs/PI) composites with low volume (≤10vol%) fraction of ceramic fillers were successfully prepared by in-situ dispersive polymerization. The BT-NWs were synthesized by a simple one-step hydrothermal method . The microstructure, dielectric properties , and energy storage density of the composites were studied. It was found that the two types of fillers were dispersed homogeneously in the PI matrix. Compared with BT-NPs/PI composites, the dielectric constant of composites filled by BT-NWs was larger at the same concentration. Stronger interfacial polarization mainly determined the dielectric properties that we observed on BT-NWs/PI composites. Furthermore, the energy storage density of the composites was significantly enhanced by BT-NWs, and energy storage density of 1.06   J/cm 3 was obtained under an electric field of 2200   kV/cm with the BT-NWs content of 2   vol%, which was 37% larger than that of the pure PI. The results indicate that the introduced wire-like ceramic fillers contribute to the enhancement of the dielectric properties and energy storage density of the composites.