高能量密度电容器用无机介电材料

Capacitor is an important basic element in modern electronic industry. With the motivation of high-perfomance electrical power,new energy and advanced weapon systems, development of high electric energy and power density capacitors is the hot research topic. These capacitors should meet the requirements of high energy density, high breakdown voltage, fast charge-discharge efficiency, as well as high insulating characters. The energy storage density of dielectrics is correlated to dielectric constant and breakdown strength. Therefore, dielectric materials with high dieletric constants and low dielectric losses are of critical importance for wide applications. Normally, researchers focus on high dielectric ceramics, pure polymer films and nanocomposites with polymer matrix. In this project, we will prepare new polymers with high breakdown strength, and then obtain the high energy density nanocomposites by adding the o-dimension nanoparticles or 1-dimension ferroelectric/ paraelectric nanofibers. Antiferroelectric oxides thin films will be deposited on the flexible C-based substrate, which is available to realize the synergetic regulation on high dieletric constants and breakdown strength by structure designment and processing optimization. and obtain high energy density (~30J/cm3). Finally, a physical mechanism model is proposed to understand the microstructure, interface effects and electrical tansportation behaviors of the above mentioned dielectrics.

电容器一直是现代电子工业的重要基础元件。近年来由于电力电子、新能源及先进国防武器等高新技术领域的推动，研发高储能、高功率密度电容器已成为目前研究热点，需要电容器满足高的储能密度、高的工作电压、快速充放电速率以及良好的绝缘性等性能特点。电介质材料的储能密度与材料的介电常数和介电强度紧密关联。要提高介质材料的储能密度，需要同时提高介电常数和介电强度。现有材料体系主要集中在高介电陶瓷材料、单一聚合物薄膜材料，以及聚合物基纳米复合电介质材料。本项目将制备新型高介电强度聚合物材料，并引入高介电0维无机粒子或1维铁电/顺电纤维，获得高储能密度纳米复合介电材料。在柔性C基底上沉积反铁电氧化物薄膜，通过结构设计和制备工艺的控制，实现无机介质材料高介电常数与高介电强度的协同调控，以此获得高储能密度（~30J/cm3）。并弄清其微观结构、界面效应对其电学性能的影响规律，建立相应理论模型。

由于电力电子、新能源及先进国防武器等高新技术领域的推动，研发高储能、高功率密度电容器已成为目前研究热点，需要电容器满足高的储能密度、高的工作电压、快速充放电速率以及良好的绝缘性等性能特点。本项目成功制备了几种新型无机介质薄膜，在提高介电常数的同时，有效抑制了损耗，从而实现储能密度的大幅度提高；通过非平衡制备方法，获得了P(VDF-HFP)/BaTiO3高储能密度多层纳米复合介质材料，其储能密度高达30.15 J/cm3；利用高通量相场模拟研究了填料结构、空间电荷对聚合物基纳米复合材料的介电响应，初步建立了纳米复合介质的界面调制物理机制。利用准分子激光沉积制备了新型BiFeO3基无铅弛豫铁电薄膜，通过多形态纳米畴设计实现无铅电介质薄膜高储能性能，其储能密度高达112J/Cm3。进一步通过在BiFeO3-BaTiO3体系中设计超顺电结构，成功在室温附近实现超顺电相，将储能密度提高到155 J/cm3 的高储能密度，和~80% 的高储能效率，为研发高储能密度无机介质材料提供了一条新的普适性方法。共发表SCI收录论文40篇，其中1篇发表在Science上、2篇发表在Nature Communications，3篇发表在Adv. Mater上。申请发明专利7项，授权发明专利2项。在国际国内会议做邀请报告8次。