Research on structure and properties of MWCNT@PDA/polymer matrix composite films with enhanced energy storage performance

MWCNT@PDA/PVDF-TrFE and MWCNT@PDA/PVDF-TrFE-CTFE composite films with high dielectric constant, low dielectric loss and excellent energy storage density were prepared by solution casting method. The best component of composite film (2.0 wt% MWCNT@PDA/PVDF-TrFE-CTFE, named C) was selected as the middle layer of the sandwich structure, and the upper and lower layers were made up by pure PVDF-TrFE film (named A) and pure PVDF-TrFE-CTFE films (named B). By testing and comparing the microstructure and performance of the single-layer composite film and the sandwich structure composite film, the influence of the matrix and structure on the performance of the composite film was discussed. The results showed that the dispersion effect of the filler in the matrix became worse, the dielectric constant gradually increased, the dielectric loss of the composite film did not change significantly, and the energy storage density first increased and then decreased with the increasing of the filler content. At a frequency of 10(3) Hz, the dielectric constants of 2.0 wt% MWCNT@PDA/PVDF-TrFE and 2.0 wt% MWCNT@PDA/PVDF-TrFE-CTFE composite films were 9.00 and 13.88, which were 1.9 and 2.9 times of pure films. When the electric field was 1100 kV/cm, the energy storage density of composite film BCB was 6.36 times of film C.