All-organic PVDF-based composite films with high energy density and efficiency synergistically tailored by MMA-co-GMA copolymer and cyanoethylated cellulose

Abstract

All-organic polymer dielectric films have been widely used for different electrical devices in recent years. However, their development is impeded by low U_e and large device volume. In the present paper, polyvinylidene fluoride (PVDF) composite dielectric materials, with high energy density (U_e) and energy efficiency (η), were prepared through the synergistic effect of a new MMA-co-GMA (MG) copolymer and cyanoethylated cellulose. MG was miscible with PVDF, which reduced the dielectric loss (tan δ) and improved the η of PVDF due to the linear structure and the hydrogen bonding interaction with the epoxy groups for MG. To further enhance the U_e of the dielectric films, cyanoethylated cellulose (CR-C) was added as a third component into the PVDF composite matrix to improve the U_e. The deep trap effect of hydrogen bonds between PVDF/MG and CR-C improved the electric breakdown strength (E_b) of the three-phase composite films from 440 MV m⁻¹ to 640 MV m⁻¹. Moreover, the high polarization of cyanoethylated cellulose can significantly improve the U_e (24.43 J cm⁻³) of the three-phase composite dielectric film, and the efficiency can be maintained above 75% at 640 MV m⁻¹. This research provides a new idea for the manufacturing of homogeneous and stable all-organic PVDF dielectric composite films based on the hydrogen bonding construction strategy.