Excellent energy storage performance of polyvinylidene fluoride-based all-organic dielectrics via introducing semi-interpenetrating networks

Polymer film capacitors have attracted much attention in power electronic systems due to high power density and rapid charging/discharging capabilities. However, high dielectric loss under high electric fields severely limits the energy storage performance of polyvinylidene fluoride (PVDF) dielectrics. In this study, the poly(methyl methacrylate - carboxylic anhydride) (P(MMA- co -MA)) copolymer was prepared. 4, 4′-oxydianiline (ODA) was used as a crosslinking agent to introduce an amide crosslinking network into PVDF-based ternary blends (mass ratios of PVDF/PMMA/P(MMA- co -MA) = 50:25:25), which helps to further suppress the high loss of PVDF. The experiment results show that when the mass content of ODA crosslinker is 0.2 wt%, the ternary blend forms a moderate and uniform three-dimensional crosslinked network, thus effectively restricting the movement of charges and significantly reducing leakage current density and carrier hopping distance. As a result, the highest breakdown field strength of 734 MV m −1 and the maximum discharge energy density of 26 J cm −3 are achieved at room temperature. According to density functional theory, the LUMO energy level and the distribution of electrostatic potential reveal that the cross-linking points act as deep charge traps, which can increase E b . This study provides an effective method for preparing high-performance polymer dielectrics via constructing semi-interpenetrating networks.