有序BaTiO3/聚合物复合材料的构建及储能机理

Flexible high energy-storage density materials are one of the extensively developed critical energy source materials, due to their potential applications in the modern electronics, hybrid electric vehicles and pulsed-power technology fields etc.. How to make ferroelectric/polymer composites both have high dielectric constant and high breakdown strength is the key problem that needs to be solved in high-performance energy storage devices. Aimed at this problem, this applicaction will make use of a novel surface modification technology, namely, direct fluorination techology, to improve bond adhesive reactions among ceramic, interface layer and polymer, and dispersion of ceramic powders in polymer matrix, meanwhile, the plated-like BaTiO3 with the anisotropic dielectric properties is introduced into the high-thermostability polyimide (PI) matrix, and fabricating an aligned BaTiO3/PI composites through tape casting method to further improve their dielectric and energy storage properties; the influence of composition, fluorinated layer, aspect ratio, and orientation of plated-like BaTiO3 on dielectric and energy storage properties of composites would be investigated thoroughly to establish the inherent relationships among bond adhesive reactions, microstructure and properties, then the mechanism of interface fluorinated modifications would be clarified; the interface polarization behavior and the improved-dielectric mechanism would be disclosed by using the dielectric relaxation theory; and the energy storage mechanism would be revealed by systematically exploring the discharge-charge behavior and space charge distribution of composites, which would furhter provide the foundation for the practical direction of high-performance energy storage devices.

柔性高储能密度材料是目前大力发展的关键能源材料之一，在电力、混合动力汽车、脉冲功率技术等领域具有广泛应用。如何使铁电/聚合物复合材料同时具有高介电常数和高击穿场强成为高性能储能器件研发中急需解决的关键问题。为此，本项目拟采用一种新的填充物界面氟化改性技术，增强陶瓷-界面层-聚合物间的键合作用和分散性，同时利用片状结构BaTiO3介电性能的各向异性，填充到高热稳定性的聚酰亚胺（Polyimide, PI）基体中，辅以流延技术制备均匀有序的片状BaTiO3/PI复合材料，提高复合材料的介电和储能特性；系统探究片状BaTiO3的含量、氟化层、径厚比和取向对介电和储能特性的影响规律，建立键合作用-结构-性能之间的关联，阐明界面氟化改性机制；采用介电松弛理论，揭示复合材料的界面极化行为和介电增强机理；探究复合材料充放电行为和界面区域空间电荷分布，揭示储能机理，为高性能储能器件的实用化奠定基础。

针对铁电/聚合物复合材料难以同时具有高介电常数和高击穿场强这一关键问题，本项目系统探究了以聚酰亚胺为基体复合材料的介电和能量储存特性，并深入分析界面的形成及其结构对性能的影响规律。通过熔岩法制备的二维（2D）片状铁电粉体（BaTiO3, BNT等）以及通过改进的静电纺丝技术制备的一维（1D）纳米纤维引入到聚酰亚胺基体中，辅以流延技术制备均匀有序的铁电/聚酰亚胺复合材料，研究了结构、界面的改变对复合材料的介电常数、介电损耗和储能密度的影响，采用介电松弛理论，揭示复合材料的界面极化行为和介电增强机理。本课题的研究为发展高性能储能材料和器件的实用化奠定了良好的基础。研究结果发表在Ceramics International等国际学术期刊上10篇。获授权中国发明专利2项，在国际学术会议上做学术报告2次，墙报1次。培养硕士毕业或在读研究生4人。指导的2名硕士研究生先后考入天津大学和哈尔滨工业大学攻读博士学位，其中一名研究生先后获得国家奖学金、内蒙古自治区研究生创新基金资助、全国电介质物理会议等奖励。