Improving dielectric and energy storage properties in polyvinylidene fluoride via introducing Au/Ag/BaTiO3 composite skeletons

High-performance polymer composites with excellent dielectric and energy storage capabilities are urgently needed for advanced electronic power systems, but traditional strategies have been challenging to balance high dielectric constant, low loss and breakdown strength. Herein, an innovative Au/Ag/BaTiO 3 composite skeleton is prepared by loading Au/Ag bimetallic nanoparticles onto BaTiO 3 . In which, Ag nanoparticles are loaded inside of BaTiO 3 by in-situ growth. The Au nanoparticles are loaded on the surface of BaTiO 3 via physical vapor deposition. The BaTiO 3 skeleton plays a dual role in high polarization and blocking the formation of conductive pathways by metal nanoparticles. The results show that the Au/Ag/BaTiO 3 /PVDF nanocomposites exhibit a high dielectric constant of 56.6 at 10 kHz, which is 590 % higher than that of pure PVDF ( 8.2@10 kHz) due to the micro-capacitors effect induced by Au/Ag bimetallic nanoparticles. Due to the Coulomb blockade effect of Au nanoparticles, the dielectric loss of the composites is only 0.037 at 10 kHz, which is 24.5 % lower than that of pure PVDF ( 0.049@10 kHz). Notably, the nanocomposite achieves simultaneously a breakdown strength of 294 kV/mm and an energy density of 6.9 J/cm 3 , which are 141 % and 578 % of pure PVDF, respectively. Mechanical tests show that the skeleton also improves the Young's modulus of the composites (1700 MPa compared to 520 MPa for PVDF). The results demonstrate the potential of Au/Ag/BaTiO 3 composite skeletons for high-performance dielectric applications and provide a new strategy for designing advanced polymer composites.