Simultaneous improvement in dielectric constant and breakdown strength of PVDF composites containing BaTiO3@Ag nanofillers towards high-performance energy storage dielectrics

The performance contradiction between dielectric constant and breakdown strength restricted the significant improvement in energy storage density of common dielectrics. In this work, the ternary BaTiO 3 @Ag/PVDF composites were prepared, in which the fibrous BaTiO 3 fillers were prepared by electrospinning and further modified with silver (Ag) nanoparticles via silver mirror reaction. Dielectric performance of the composites was effectively improved by the hybrid fillers owing to the synergies of the increased polarizations and the Coulomb blockade effect. Dielectric constant and breakdown strength of the composites with only 0.2 wt% filling content reached 14.8 and 421.7 MV/m, which were respectively increased 124.4% and 135.9% compared to that of the pristine PVDF. And the maximum energy storage density was increased to 4.5 J/cm 3 with the ultra-low content of fillers. This work broke the inherent contradictions in single-layer composites and provided novel attempts for dielectric modulation of dielectrics.