▎ 摘　　要

An ultra high dielectric constant nanocomposites comprising of poly(vinylidene fluoride) (PVDF) as a polymer matrix and niobium pentoxide (Nb2O5)-reinforced graphene oxide (GO) have been successfully developed using solution casting technique. Scanning electron microscopy (SEM) demonstrates that the homogeneous dispersion of Nb2O5 and GO within the PVDF matrix was realized. The dielectric and electrical properties of the resulting PVDF-GO-Nb2O5 nanocomposite films as a function of frequency were studied. The dielectric constant of the nanocomposites system reached a value of about approximate to 140 at 100 Hz, with a relatively low dielectric loss factor (approximate to 1.4). The enhanced dielectric performance of the PVDF-GO-Nb2O5 nanocomposites was ascribed to the presence of Nb2O5 onto the GO, which exhibits strong interaction between GO and PVDF matrix through hydrogen bonding. Moreover, the experimental results fit well with percolation theory and near the percolation threshold (fc < 2 wt %) with high dielectric constant was achieved for PVDF-GO-Nb2O5 nanocomposites. Furthermore, the AC electrical conductivity was also noticeably enhanced. Our strategy provides a facile method to prepare high dielectric constant and relatively low dielectric loss PVDF-GO-Nb2O5 nanocomposite films that might be suitable for energy storage applications.