Structural design and enhanced energy density of Ba0.6Sr0.4TiO3/PVDF nanocomposites with multilayer gradient structure

With the development of science and technology, the application of electronic products is extensive, and it is developing in the direction of miniaturization, integration, and high performance. However, the development of electronic products is limited due to capacitors low energy storage density. This study selects inorganic nanoparticles with high dielectric constant as fillers and polyvinylidene fluoride as the matrix of composite materials. It adopts a layer-by-layer casting method to prepare multilayer Ba0.6Sr0.4TiO3/PVDF composites. It is found that the dielectric and energy storage performances of the multilayer composites doped with Ba0.6Sr0.4TiO3 are improved compared with the pure PVDF polymer films after the electrical properties test. A multi-layer composite material with a gradient distribution of fillers was designed and prepared to improve the energy storage density. The energy storage density of multilayer composites with a favorable gradient structure can reach up to 9.3 J/cm3 at 300 kV/mm. By analyzing the improved storage density mechanism, the results show that the design of the multilayer gradient structure can significantly reduce the electric field's local concentration, inhibit the formation of conductive paths, and significantly improve the composites' energy storage density.