Evolution of nanopolar phases, interfaces, and increased dielectric energy storage capacity in photoinitiated cross-linked poly(vinylidene fluoride)-based copolymers

Photoinitiated cross-linking of poly(vinylidene fluoride-co-chlorotrifluoroethylene) can offer a significant increase in electric energy storage capacity. This improvement is related to the structural changes in the copolymer crystals brought by cross-linking. Cross-linking favors formation of polar crystalline phase, drastic reduction of spherulite sizes, and increase in copolymer inner interface area. This copolymer case demonstrates the greatly enhanced energy storage behavior, including increased discharge energy density at reduced field strength, and improved capacitor efficiency at relatively high degree of cross-linking, which may facilitate a better design for polymer dielectric materials in their application of high energy density capacitors.