Configurational approach to the enhancement of the dielectric properties and energy density of polyvinylidene fluoride-based polymer composites

Abstract

Polyvinylidene fluoride (PVDF)-based polymers are promising dielectric materials, owing to their higher breakdown strength and energy density than conventional ceramic-based dielectric materials. Nevertheless, the energy density of the polymers is lower than expected, highlighting the need for improvement before they can be applied commercially. As one method to solve this issue, the P(VDF-HFP) copolymer and P(VDF-TrFE-CFE) terpolymer have been mixed at various compositions, because both the high breakdown strength of the copolymer and the dielectric constant of the terpolymer can be combined. Depending on the configuration of the two polymers, such as the 3–3 composite or 2–2 composite, the strength of their properties also contributes differently. From blended films of a 3–3 composite, P(VDF-TrFE-CFE) terpolymer and P(VDF-HFP) copolymer films with a 9:1 composition showed the highest energy storage capability as well as excellent dielectric properties. The remnant polarization and breakdown strength of the blended films were 1.83 µC cm−2 and 250 MV m−1, respectively. Multilayered films of the 2–2 composite with the same composition exhibited a considerable energy storage of 40 J cm−3 owing to the low remnant polarization of 5.15 µC cm−2 and large breakdown strength of 500 MV m−1. Consequently, multilayered PVDF-based polymer films showed good potential for high power energy and electrostatic capacitor applications because of their remarkable energy density and breakdown strength.