≤10nm钛酸钡颗粒调控的高性能聚合物基复合材料的储能机理研究

Dielectric capacitors are irreplaceable energy-storage components in pulsed power systems, which are widely applied in electric and electrical industry. Developing materials with high dielectric constant as well as high breakdown strength is very important in improving the energy density of dielectric capacitors. As most of the high-polarization ceramic fillers deteriorate the dielectric strength of the polymer composite, this project will develop nanocomposite films based on ultrafine (≤ 10 nm) BaTiO3 ferroelectric nanocrystal fillers to solve the problem. The ultrafine fillers with specific physical, chemical, electrical and interface characteristics can optimize the microstructure and charge distribution of the composite, therefore effectively improve the electric displacement while maintain the initial high breakdown strength of the composite. Dielectric composite films with energy density ≥20 J/cm3 will be prepared. This project combines various experimental methods, including nanotechnology, coating and multilayer design, and finite element and phase field simulations to detect the influence of the ultrafine ferroelectric nanocrystals on the dielectric performance of the polymer nanocomposite films, which provides a new technological way for the design of high energy-density composite films.

电介质电容器是智能电网、大功率激光武器、新能源技术等领域不可替代的重要储能元件，在电子和电气工业中具有广泛的应用。研发兼具高介电常数和击穿场强的介质材料是提升电介质电容器储能密度的关键。针对现有陶瓷-聚合物基复合材料体系中，无机填充相导致的击穿场强恶化的关键问题，本项目提出基于≤10nm的BaTiO3铁电颗粒的聚合物基介电复合材料，拟通过极细尺寸铁电颗粒特殊的物理、化学、电学及界面等纳米尺寸效应，调控复合材料的显微结构和电荷、电场分布，有效提升复合材料的电位移极化并保持其耐击穿性能。综合运用纳米制备、包覆改性、多尺度结构设计的实验手段，结合有限元分析、相场模拟的理论方法，研究≤10nm钛酸钡颗粒的纳米尺寸效应，探明其对复合材料储能特性的影响机理，设计制备一系列储能密度≥20J/cm3的复合电介质薄膜，为高储能密度介电复合材料的发展提供一种新的技术路径。

电介质电容器是电子电力系统中应用最为广泛的基础元器件之一，近年来随着可再生能源新技术的快速发展而成为了储能领域研究的热点前沿。薄膜型电介质电容器实现性能突破的关键在于两相界面的设计和调控。本项目针对现有陶瓷-聚合物基复合材料体系中无机填充相导致的击穿场强恶化的关键问题，系统研究了基于≤10nm的钛酸钡铁电颗粒的聚合物基介电复合材料，就其填充粒子的设计与制备、复合薄膜的设计与制备、储能特性的提升机理等方面进行了系统、深入的研究。制备了一系列超细纳米晶粒子及其复合结构，探明了这些纳米晶粒子的微观结构与性能；制备了一系列高储能密度介电储能薄膜，实现了储能密度的大幅度提升；厘清了超细晶纳米铁电粒子对于复合薄膜性能提升的机理，为超细纳米粒子在复合薄膜储能体系中的进一步应用奠定了扎实的基础。