双层核壳结构钛酸锶钡基储能陶瓷的制备、性能调控及相场模拟

One of the key issues to promote the development of miniaturization, light-weight pulsed power systems is developing dielectric materials with high energy storage density. In this project, environment-friendly barium strontium titanate-based (BST) ceramics with high dielectric constant and low dielectric loss will be developed. BST@A@B (A=TiO2, ZrO2; B= SiO2, Al2O3, MgO) ceramics with double core-shell structure will be synthesized by wet chemical method and spark plasma sintering. The effects of phase composition, microstructure and preparation process on the energy storage performance will be systematically investigated. The key role of the intermediate layer (TiO2 or ZrO2) in tuning energy storage properties will be clarified. Enhanced dielectric breakdown strength and energy storage density of BST-based ceramics will be achieved. Additionally, an electro-thermo-mechanical phase field model will be proposed to simulate the breakdown behavior in ceramics. Quantitative analysis of local electric field distribution and space charge distribution will be performed and the interface effects on the energy storage performance will be addressed. This project will provide valuable theoretical basis and experimental guidance for the design and preparation of dielectric materials with high energy storage density.

开发高储能密度的电介质材料是推动脉冲功率系统小型化和轻量化发展的关键所在。本项目拟选取介电常数高、介电损耗小且环境友好的钛酸锶钡(BST)基陶瓷作为研究对象，采用湿化学法对其表面进行改性并结合放电等离子烧结技术制备BST@A@B (A=TiO2, ZrO2; B= SiO2, Al2O3, MgO) 双层包覆核壳结构复相陶瓷。系统地研究核壳成分、微结构和制备工艺对储能性能的影响规律，阐明中间层(TiO2或ZrO2)在性能调控中所起的关键作用，实现BST基复相陶瓷介电强度和储能密度的显著提高。此外，基于电-热-机械三者耦合的静电击穿相场模型，对复相陶瓷的击穿过程进行数值模拟，定量分析其内部局域电场分布和空间电荷分布，揭示核壳结构的界面效应和储能性能之间的关系，为高储能密度复相材料的设计和制备提供有价值的理论依据和实验指导。

高储能密度电介质材料在脉冲功率领域具有不可替代的作用。本项目选取介电常数高、介电损耗小、室温下为线性电介质且环境友好的钛酸锶钡(BST)基陶瓷作为研究对象，通过湿化学法和放电等离子烧结制备了多种BST基双层包覆核壳结构复相陶瓷。首先，利用葡萄糖水热法对BST表面进行了碳化处理，保证了后续壳层物质的均匀包覆；然后，利用先进的放电等离子烧结工艺在极短的保温时间下获得了超高致密度的复相陶瓷；接着，系统研究了核壳成分、微结构和制备工艺对储能性能的影响规律，阐明了TiO2中间层在性能调控中所起的关键作用，主要是调控了局域电场分布，显著提高了复相陶瓷的介电强度。最终，在BST@TiO2@SiO2和BST@TiO2@Al2O3双层包覆核壳结构复相陶瓷中实现了储能密度的显著提高（>1.6 J/cm3）。此外，本项目构建了电-热-机械三者耦合的静电击穿随机模型，并对单层包覆和双层包覆复相陶瓷的击穿过程进行了数值模拟，对其临界击穿电场进行了预测，揭示了核壳结构的界面效应和储能性能之间的关系。综上所述，项目圆满完成了预期研究目标。