电介质电容器是一种广泛应用于消费电子、交通运输、电力输送、能源存储以及航天航空等重要领域的电子元器件。其中，作为电容器主要应用方向的能量存储器件，因电容器材料独有的耐高电压和高功率密度等特点而具有不可替代的作用。在电子材料和能源存储领域大容量、集成化、小型化的快速发展趋势下，电容器材料的储能性能面临不断更新的更高的要求。然而，目前商用的电容器材料双向拉伸聚丙烯（BOPP），虽然具有较为优异的低损耗性能，但是其储能密度仅有2 J/cm3左右，极大限制了电容器材料产业的进一步发展。因此，本文围绕提高电容器材料储能密度这一目标，利用复合效应及微介观结构调控，制备了不同的复合材料体系，实现了储能密度和高效率协同提升，并以此为基础探索了新型薄膜材料在电容器器件方面的应用推广。本文首先关注有机无机复合材料，利用砂磨法对制备的铌酸钾钠陶瓷（KNN）颗粒进行尺寸调控，制备了具有高储能密度的KNN/P(VDF-HFP)复合材料。但是，简单的有机无机界面会带来材料储能效率下降的问题，为此发展了一种用于介电材料领域的新方法——相分离法。通过合成芳香族聚硫脲聚合物（ArPTU）并将其与聚偏氟乙烯-六氟丙烯共聚物（P(VDF-HFP)）基体材料共混，制备了高性能全有机复合材料。全有机材料中形成的自发界面起到了束缚材料内部自由电荷的作用，从而降低材料内部的漏导，并且提高材料的击穿强度，进而获得了同时兼顾高储能密度（~24.4 J/cm3）和高储能效率（~82%）的复合材料。在此基础上，考虑PVDF基复合材料本征高损耗的问题，选取了线性聚合物基体聚醚酰亚胺（PEI），沿用相分离思路，流延法制备了ArPTU/PEI复合材料。ArPTU材料在PEI基体中以“盘状”结构析出，粗糙表面促进两种非晶态线性聚合物的致密结合，构筑了良好的交互界面，大幅提高了材料的击穿场强和储能密度，展现了较强的器件应用潜力。以此为基础，通过与友方厂家合作，完成了PEI材料连续流延成型工艺制备薄膜材料，并设计制备了新型电容器原型器件，取得了中试试验和器件设计与应用的初步成果。
Dielectric capacitors are widely used in consumer electronics, transportation systems, power transmission, energy storage, aerospace industry and other important fields. Among them, as the main application direction of energy storage devices, capacitors play an irreplaceable role because of the unique characteristics of dielectric materials, such as high voltage resistance and high power density. With the rapid development trend of large capacity, integration and miniaturization in the field of electronic materials and energy storage systems, the energy storage performance of capacitor materials is constantly facing new and higher requirements. However, although the biaxially oriented polypropylene (BOPP) material widely used in the market has excellent low loss properties, its energy storage density is only about 2 J/cm3. The low energy storage density limits the further development of capacitor materials. Therefore, this paper adopts the method of composite materials, focuses on the goal of improving the energy density of dielectric materials, regulates the microstructure and dielectric properties of different composite material systems, prepares composite materials with ultra-high energy density and efficiency, and explores the application of new thin film materials in capacitor devices.At the beginning, we focused on organic-inorganic composites, and prepared KNN/P(VDF-HFP) composites with high energy storage density by controlling the size of potassium sodium niobate ceramic (KNN) particles by bead mill method. However, the simple organic-inorganic interface will reduce the energy storage efficiency of materials. Therefore, we have developed a new method for the field of dielectric materials - phase separation method. By synthesizing aromatic polythiourea (ArPTU) and blending with P (VDF-HFP) matrix, the formation of all organic in-situ interface plays a role in binding the internal free charges in the material, and a composite with high energy storage density (~ 24.4 J/cm3) and high energy storage efficiency (~ 82%) is obtained. Considering the problem of intrinsic high loss of PVDF matrix composites and following the idea of phase separation, we prepared ArPTU/PEI composites. The results show that the combination of two amorphous linear polymers constructs a good interactive interface, greatly improves the breakdown field strength and energy storage density of composites, and shows a strong device application potential. Therefore, through cooperation with cooperative factories, we have completed the continuous casting process of PEI materials. On this basis, we designed and prepared new capacitor device samples, and achieved preliminary results in pilot test for device design and application.
