▎ 摘　　要

Polymer film capacitor exhibits extensive applications in advanced electronics because of its flexibility and huge power density. The current research interests of polymer capacitor are addressed on large energy density and high charge-discharge efficiency of composite film. Here we developed the compatible elastic interface composed of hyperbranched poly(methyl acrylate) copolymer in graphene/poly(vinylidenefluoride-trifluoroethylene-chlorofluoroethylene) (P(VDF-TrFE-CFE)) nanocomposite with high energy capability. This hyperbranched copolymer comprising polyethylene core that was grafted with poly(methyl acrylate) (PMA) segments and pyrene units was synthesized by atom transfer radical polymerization. The few-layer graphene was exfoliated with assistance of hyperbranched copolymer that was attached on surface of flakes via pi-pi non-covalent interactions between pyrene groups and delocalized pi electrons of nanosheets. Graphene/P(VDF-TrFE-CFE) nanocomposite film was prepared by solution casting method. The compatibility between graphene and fluoropolymer is greatly improved due to the elastic interphase of PMA segments in hyperbranched copolymer, which enhances the interfacial polarization and decreases the accumulation of charge carriers under high electric field. The energy density of 7.0 J/cm(3) with charge-discharge efficiency of 60% at 300 MV/m is achieved for 0.1 wt% nanocomposite. This work reveals an effective architecture of polymer composite with elastic interface to increase the energy capability of polymer dielectric film.