Effect of functionalization of Ba Sr TiO3 on dielectric and energy storage behavior of PVDF Ba Sr TiO3 nanocomposites

Abstract

High-energy density capacitors are essential components in modern electronics due to their application in pulsed power systems such as military, aerospace and hybrid electric vehicles. The high energy density capacitors store large amounts of electrostatic energy per unit volume, which is readily available for delivering to a load in a very short span of time. There are certain ceramic materials which are found to exhibit extremely high energy density in the form of thin films, but they cannot be processed over larger areas in the capacitors constituting energy banks. The dielectric polymer-ceramic nanocomposites have the ease of processability in the form of flexible thin films, which could serve the purpose of high energy density as well as miniaturization of modern electronic devices. These electronic devices, e.g., avionics in aerospace cover 70% of its volume by capacitors. Despite of having high mechanical and breakdown strength, the dielectric polymers have a drawback of low dielectric constant. On the other hand, the ceramics have high dielectric constant but relatively very low breakdown strength. Therefore, dielectric polymer ceramic nanocomposites having a moderate dielectric constant, high breakdown strength and low tangent loss could serve the purpose of high energy density capacitor materials. A large number of polymers are used as a matrix, such as polyvinyl chloride (PVC), polyethylene terephthalate (PET), polyvinylidene fluoride (PVDF), etc., with particular interest surrounding PVDF due to its favorable functional attributes, high breakdown strength, flexibility, and ease of processing. On the other hand, some examples of ceramics fillers are PbZrTiO3 (PZT), PbTiO3 (PTO), BaTiO3 (BTO), BaSrTiO3 (BST), HfO2, etc., which are highly appealing for their applications in various fields as they have high dielectric constant. Among these ceramic fillers, barium strontium titanate (BST) exhibits an exceptionally high dielectric constant (e.g., 2500-3000) at room temperature and maintains a nearly