Interface fabricating to improve the dielectric and energy storage properties of P(VDF-co-CTFE)/BST composites

High-activity barium strontium titanate (BST) nanoparticles with diameter of 50nm were synthesized via sol-gel method. The BST particles were surface modified with a silane coupling agent (KH550). After that, the BST nanoparticles were then compounded with poly(vinylidene fluoride-co-chlorotrifluoroethylene) (P(VDF-co-CTFE)) in 0-3 connecting form. Using solution casting method, P(VDF-co-CTFE)/BST nanocomposite thick films were prepared on quartz slides. And water-quenching experiments were finally performed on the composite thick films. XRD, TEM, TGA, and FE-SEM were used to characterize the BST particles and the obtained films. Results indicate that the interface of the BST nanoparticles has been effectively improved by surface modification with KH550. Compared with the nanocomposite films with uncoupled BST particles, the ones with KH550-coupled BST particles possess higher dielectric constant (>33), larger breakdown electric field (>270 MV/m), and lower dielectric loss. Moreover, the surface modification is also helpful to improve the film saturation polarization (P _s), and decrease the film remnant electric polarization (P _r), thus finally enhancing the film electrical energy density (>6.8 J/cm ³ for a film sample with BST of 10vol%). The overall results indicate that the surface modification for polymer/ceramic compounds shows great potential in the field of high-energy storage devices.