Capacitive energy storage materials possess the advantages of high energy density and speedy charge-discharging capability. In particular, polymer-based dielectric materials for high temperature operation condition are increasingly demanded for numerous emerging applications such as electric vehicles or aerospace power conditioning. So far, a common way to improve the energy density is to incorporate wide bandgap inorganic materials or constructing complex and sophisticated copolymers. To overcome such obstacles, a team from DESY and Jilin University in Changchun (China) leveraged the intrinsic formation of nanocrystallites in semicrystalline polymers to develop a single component homopolymer-based dielectric material that can operate efficiently at high temperatures of about 200°C and high electric fields of 500 MV/m. The results were published in Angewandte Chemie, International Edition.
“The intrinsically formed polymer crystallites are usually lamellae-like with a thickness of tens of nanometers. Can these crystallites achieve the same role as the nano-fillers in those inorganic-organic composite dielectric materials? It will consist of single components which simplifies material processing and makes it easily scalable.” says Wenhan Xu, the Helmholtz-OCPC postdoctoral fellow at DESY and Jilin University. Through rational molecular structure design, he produced a semicrystalline polymer film by using poly(diarylene ether naphthylamide) (PEENA). Its high-temperature capacitive performance outperforms all commercially available dielectric polymers (e.g. polyetherimide (PEI)) measured at the reference condition of 10 Hz and 200°C.
Read more on DESY website
Image: Hierarchical structure of semicrystalline polymers: (left) Schematic diagram of the hierarchical structure of semicrystalline polymers from polymer chains to lamellae to polymer films. Sketch of the X-ray scattering of polymer films with (right) 2D XRD scattering patterns of semicrystalline PEENA films (vertical direction is aligned with the film normal)
Credit: C. Shen, DESY (partly from original publication)