【摘要】 高温介电聚合物在高温静电储能薄膜电容器中有着广阔的应用。然而，目前常规的高温聚合物电介质介电常数与能量密度较低，这限制了其在高温环境中的应用。为进一步提高高温电介质材料在高温下的介电及储能特性，本研究以聚偏氟乙烯（polyvinylidene fluoride,PVDF）为填料，聚酰亚胺（polyimide,PI）为基体，采用原位聚合方法制备了全有机PVDF/PI复合电介质薄膜。系统地研究了铁电PVDF相含量对PI微观结构与形貌、介电性能、储能特性、以及热性能等影响。结果表明：PVDF填料在PI基体中具有良好的相容性和分散。PVDF的引入会使得PI基复合薄膜的击穿强度出现一定程度的下降，但是可以明显提高复合薄膜的介电常数和放电能量密度。其中，PVDF添加质量分数为30的复合薄膜在室温和250 MV/m条件下放电能量密度达到1.89 J/cm~3，充放电效率为92.4%；而100℃和200 MV/m条件下的放电能量密度达到1.13 J/cm~3，充放电效率为89.1%。此外，PVDF/PI复合薄膜在高温和高电场的恶劣条件下具有良好的充放电循环性能以及热稳定性。该研究为改善聚合物基复合电介质在高温环境中的储能特性提供了一种新的设计思路。更多还原

【Abstract】 High-temperature dielectric polymers have broad application potential in high-temperature electrostatic energy storage film capacitor. However,the low dielectric constant and energy density of conventional high-temperature polymer dielectrics limit their application in high temperature environment.In order to improve the dielectric and energy storage performances of high-temperature dielectric materials at high temperatures further,all-organic PVDF/PI composite dielectric films are prepared with polyvinylidene fluoride(PVDF)as filler and polyimide(PI)as matrix through in-situ polymerization method in this study. The effects of ferroelectric PVDF phase on the microstructures,morphologies,dielectric properties,energy storage properties,and thermal properties of PI are systematically studied. The results show that PVDF fillers have good compatibility and dispersion in PI matrix. The introduction of PVDF reduces the breakdown strength of the PI-based composite film to a certain extent,but can significantly improve the dielectric constant and discharge energy density of the composite films. PVDF/PI composite films with 30 wt.% PVDF exhibit a discharged energy density of 1.89 J/cm~3and a charge-discharge efficiency of 92.4% at room temperature and 250 MV/m,and those of 1.13 J/cm~3and the chargedischarge efficiency of 89.1% at 100 °C and 200 MV/m. In addition,the PVDF/PI composite films possess excellent charge-discharge cycle performance and thermal stability under high temperature and high electric field conditions. This study provides a new design idea for improving the energy storage performance of polymer-based dielectrics in high-temperature environments.更多还原