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

Abstract 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.