Dielectric energy storage properties of 0-3 type BST/PVDF composite films

Spin coating was used to fabricate 0-3 type BST/PVDF nanocomposite dielectric films using high-concentration suspensions. Polyvinylidene fluoride (PVDF) served as the matrix material, incorporating Ba0.8Sr0.2TiO3 (BST82) and Ba0.6Sr0.4TiO3 (BST64) nanoparticles, each with a particle size of 200 nm. This study investigates the microstructure, dielectric properties, dielectric temperature spectra, and energy storage performance of the BST/ PVDF nanocomposite films with varying volume fractions of BST nanoparticles. The results reveal that as the volume fraction of BST82 and BST64 increases, the dielectric constant, maximum polarization, and remanent polarization increase, while the breakdown field strength decreases. The dielectric constant of the 0-3 type nanocomposite films incorporating BST fits best with the Jayasunder-Smith model across a range of 0 vol% to 20 vol%. Moreover, the maximum discharge energy storage densities of the BST82/PVDF and BST64/PVDF nanocomposite films, at a BST volume fraction of 7 vol%, are 5.74 J/cm3 and 4.21 J/cm3, respectively, under field strengths of 310 MV/m and 270 MV/m. Notably, analysis of the dielectric temperature spectrum reveals that high-temperature dielectric relaxation is primarily governed by the PVDF matrix, with the nanoparticle fillers having no significant impact on this phenomenon. In conclusion, both BST82 and BST64 nanoparticles influence the performance of the polymer films, with BST82-based nanocomposites showing higher breakdown field strength. This study provides valuable insights into the fabrication of high-performance 0-3 type nanoparticle/ polymer dielectric nanocomposite films using concentrated BST/PVDF nanosuspensions and the spin coating method.