n-Type Semiconductive Polymer and Poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) Blends for Energy Storage Applications

Dielectric polymers play a vital role in modern electronic and electrical application because of easy processing, light weight, and high breakdown strength. A high dielectric constant (εr) and breakdown strength cannot be satisfied simultaneously in the dielectric homopolymers. Via combining the merits of different polymers, the dielectric polymer blending method is a feasible option to address this issue. In this paper, n-type semiconductive polymer poly(1,6,7,12-tetra-chlorinated perylene-N-2-aminoethyl acrylate-N′-dodecylamine-3,4,9,10-tetracarboxylic bisimide) (PPDI) and relaxor ferroelectric polymer poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) (PVTC) were utilized to prepare the dielectric polymer blends because PPDI had the characteristic of binding electrons and PVTC possessed a high εr. A series of polymer blends with different weight ratios of PPDI were fabricated to investigate the loading effect of an n-type semiconductive polymer on the dielectric and energy storage properties of PPDI/PVTC blends. The experimental results showed that, when the loading was below 3 wt %, the εr of polymer blends increased from 25 to 33 at 102 Hz with the increasing content of polymer PPDI and then decreased from 33 to 7 with the increasing concentration from 3 to 40 wt %. The dielectric behavior of polymer blends was related to the dispersion of organic fillers and interface polarization. Additionally, a low dielectric loss was found in all polymer blending films. A maximal discharge energy density of 4.42 J/cm–3 was achieved in the 4.5 wt % PPDI/PVTC blending film at 200 kV/mm–1. The finding presents an innovative idea to synthesize high-performance all-organic dielectric materials.