Study On The Influence Of N-type Semiconducting Polymer Fillers On The Dielectric And Energy Storage Performances Of All-organic Polymer Films

All-organic dielectric materials with good processing properties,flexibility and excellent electrical properties have good development prospects in modern power supply and renewable energy systems.However,the low dielectric constant and low energy density limit their development.The energy storage density of a single polymer cannot meet requirement of the developing industrial.The improvement in dielectric constant and the upsurge in breakdown field strength can achieve high energy density.At present,the preparation of polymer-based dielectric organic composite materials(polymer alloys)is an effective strategy to solve the low dielectric constant and low energy storage density of polymers.The n-type semiconducting polymer-poly(1,6,7,12-tetrachloroperylene-N-acrylic acid-2-aminoethyl-N?-dodecylamine-3,4,9,10-tetracarboxylic bisimide)(PPDI)has the characteristics of high electron mobility,well dissolution processing performance,and easy synthesis.Therefore,n-type semiconducting polymer is an ideal organic filler for preparing polymer-based dielectric composites.In this paper,for the first time,n-type semiconductors(PPDI)were introduced into ferroelectric polymers(poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene),PVTC)and high-temperature-resistant linear dielectrics(polyetherimide,PEI),in order to obtain dielectric material with a high-dielectric constant or a high-energy density,high-efficiency and high-temperature resistant.The specific research content was as follows:In the first part,an n-type semiconducting polymer PPDI was synthesized through a series of organic reactions.Furthermore,a series of PPDI/PVTC blends were gained by the solution casting method.The impact of PPDI on the dielectric and energy storage performance of PPDI/PVTC blends was investigated in detail by impedance analyzer and ferroelectric analyzer.The experimental results showed that when the content was less than 3 wt%,the dielectric constant(?_r)of the polymer blend increased from 25 to 33 at 100 Hz with the upsurge of the polymer PPDI content.Then,as the concentration increases from 3 wt%to 40 wt%,?_rdecreased from 33 to7.The change rule of the dielectric properties of polymer blends was related to the dispersibility and interface polarization of organic fillers.In addition,all polymer blend films exhibited low dielectric loss.Under the electric field intensity of 200k V/mm,the maximum discharge energy density of the 4.5 wt%PPDI/PVTC blend film was 4.02 J/cm~3.In the second part,in order to study the influence of the content of n-type semiconducting polymer on the dielectric and energy storage properties of PEI-based organic composites,a series of PPDI/PEI blended films were obtained by the solution blending method.In addition,the effect of temperature on the permititivity and energy storage properties of the composite material and the impact of the number of cycles on the stability of the material were investigated.The research results indicated that the maximal dielectric constant of 7 was achieved in 4 wt%PPDI/PEI at 10~3Hz and room temperature.At 150°C,the dielectric constant of 3 wt%PPDI/PEI stabilized at around 5.At 100?,the energy efficiency of 82%was obtained in 1 wt%PPDI/PEI,and the energy storage density remained at 5.12 J/cm~3.This paper studied the rule of n-type semiconductors PPDI on the dielectric andenergy storage of ferroelectric PVTC and high-temperature-resistant linear dielectrics PEI,and furnished a new idea for synthesizing new dielectric materials with high?_r,low dielectric loss and high energy storage density.