High-field antiferroelectric behaviour and minimized energy loss in poly(vinylidene-co-trifluoroethylene)-graft-poly(ethyl methacrylate) for energy storage application

In this work, we report a novel antiferroelectric-like performance at high poling fields obtained in poly(ethyl methacrylate) (PEMA) grafted poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) series copolymers for application as high energy density and low loss capacitor dielectrics films. Compared with the pristine P(VDF-TrFE) random copolymer, an enhanced discharged energy density but a lowered energy loss has been observed as more PEMA is grafted. This novel antiferroelectric-like behavior at high poling field was explained by the crystalline impediment and polarization confinement effect induced by PEMA side chains. The highest discharged energy density of 14 J cm^-3 and a low loss of 30% at 550 MV m^-1 are achieved in the sample containing 22 wt% PEMA. This finding represents one of the effective routes to design potential dielectric polymer films for high energy storage applications.