Effect of Inorganic Nanoparticles on Energy-Storage Properties of P(VDF-HFP)-Based Nanocomposites

Polyvinylidene fluoride (PVDF) and its copolymers have been widely used in polymer-based film capacitors due to their relatively high permittivity and electrical displacement compared with other polymers. Herein, poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) is selected as the polymer matrix, and 0.5 (Bi0.5Na0.5)TiO3-0.5(Sr0.85Sm0.1)TiO3 (BNT-SST) nanoparticles are added as the filler into the polymer to prepare BNT-SST/P(VDF-HFP) nanocomposites. The microstructure, electrical properties, mechanical properties, and energy-storage properties of the nanocomposites are investigated. The addition of BNT-SST nanoparticles improves the dielectric characteristics and breakdown strength of the nanocomposites. Particularly, when the BNT-SST filler content is 0.7 vol%, the highest breakdown strength reaches 545 MV m(-1), which is 1.3 times higher than pure P(VDF-HFP). In addition, the insulation and mechanical properties of BNT-SST/P(VDF-HFP) composite films are improved. The highest direct current resistivity and Young's modulus obtained by 0.7 vol% BNT-SST/P(VDF-HFP) nanocomposites are 6.8 x 10(13) omega cm and 1.94 GPa, respectively. More importantly, at 545 MV m(-1), the energy-storage density and efficiency of 0.7 vol% BNT-SST/P(VDF-HFP) composites are 19.07 J cm(-2) and 67.01%, respectively, which are better than other polymer matrix composites. These findings suggest that the addition of inorganic nanoparticles has important research implications for improving the energy-storage performance of polymer-based film capacitors.