Dielectric and energy storage properties of all-organic sandwich- structured films used for high-temperature film capacitors

Dielectric polymers with ultrahigh power density are widely utilized in the fields of modern electronics and power systems. This article proposes the all-organic sandwich-structured films with ferroelectric polymer poly (vinylidene fluoride-hexafluoropropylene) and linear polymer poly (ethylene tere-phthalate) (PET) as the energy storage dielectrics for film capacitors. The morphological characteriza-tions, thermal, dielectric, and energy storage performances have been investigated to evaluate the comprehensive properties of the sandwich-structured films. Excellent interlaminar interfaces are observed between poly(vinylidene fluoride-hexafluoropropylene) and PET layers. Compared with pure PET films, the sandwich-structured films exhibit improved thermal stability and dielectric constant, but some degradation in loss factor and breakdown strength. With the increase of ambient temperature, the sandwich-structured films still show improved and stable dielectric properties and insulating strength up to 125 & DEG;C. The sandwiched all-organic film shows an improved energy density (Ud) as high as 8.2 J/ cm3 and concurrently an immense charge-discharge efficiency of 86.4%. This strategy offers a feasible idea to enhance the thermal, dielectric, and energy storage capability of dielectric films with a layered architecture, which facilitates the evolution of flexible film capacitors.(c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

This study proposes an all-organic sandwich-structured film as an energy storage dielectric material for film capacitors, using poly(vinylidene fluoride-hexafluoropropylene) and poly(ethylene tere-phthalate) as the materials and conducting comprehensive performance tests. The results show that the sandwich-structured film has excellent interlaminar interfaces, improved thermal stability and dielectric properties, but some degradation in loss factor and breakdown strength. With the increase of temperature, the film still maintains stable performance and exhibits high energy density and charge-discharge efficiency.