Improved energy density and dielectric properties of P(VDF-HFP) composites with TiO2 nanowire clusters

Dielectric composites are of great demand in the micro-electronics industry. To enhance the energy storage density of the composites, TiO2 nanowire clusters was synthesized by a hydrothermal method and incorporated into the P(VDF-HFP) polymer matrix in this work. The microstructure, dielectric properties of the prepared film were discussed and the effects of TiO2 loading on the energy density were investigated. The results shows that the TiO2 clusters were tightly blended to the P(VDF-HFP) matrix owing to the dopamine-modified interface. The dielectric constant increased with the loading of TiO2, the maximum dielectric constant reached 12.04 with 7.5 vol% TiO2 loading at 1 kHz, as compared to 5.01 for the neat P(VDF-HFP). The enhanced dielectric constant was attributed to the interface polarization originated from the large interface area between the TiO2 nanowire and polymer matrix. The discharged energy density of the composite significantly increased to 1.35 J/cm3 with 7.5 vol% TiO2 nanowire clusters, which was two times higher than that of the neat P(VDF-HFP) at the same condition. The findings of this work can shed a light on improving the energy density of energy storage device via morphology modification.