铁酸铋基超晶格电介质储能材料的设计、制备与性能研究

电介质储能材料以其高功率密度、响应快速等优点有着广泛的应用。然而，它的储能密度相对较低，是制约电磁装备小型化的瓶颈之一。铁电/介电超晶格是近年来人工设计的一种新型材料，它可以提高材料的整体击穿场强和饱和极化并降低其剩余极化，从而提高储能密度。在本项目中，申请团队拟采用计算材料学方法结合材料制备、表征和性能测试来设计和获得具有高储能密度的铁酸铋/钛酸锶超晶格材料。基于相场模拟可以设计具有局域负介电常数的铁电涡旋、斯格明子等拓扑相以提高材料的总体介电响应，而电介质击穿随机模型可以预测其临界击穿场强和击穿路径。在弄清其构效关系的基础上，结合实验验证反馈以获得具有高储能密度(>100 MJ/m3)的超晶格材料。最后，研究材料和器件在力、热、电等多外场下的耦合响应，为提高其在极端环境下的综合稳定性奠定基础。本项目的顺利开展将极大地丰富凝聚态物理理论，并为大幅度提升电磁炮等新型电磁装备性能奠定基础。

Dielectric energy storage materials with high power density and fast response have broad applications. However, their energy density is relatively lower than the chemical power sources, which is one of the bottlenecks for the miniature of the electromagnetic devices. Ferroelectric/dielectric superlattice is a novel material that has been artificially designed recently, which could greatly increase the breakdown strength and the saturation polarization while decreasing the remnant polarization, leading to the enhancement of the dielectric energy storage density. In this project, we aim to employ computational materials science as well as materials synthesis, characterization, device fabrication, and property evaluation to design and obtain BiFeO3/SrTiO3 superlattice material with high dielectric energy density. Based on the phase-field simulations, topological structures such as polar vortex and skyrmions with negative capacitance can be designed, which could boost the overall dielectric response of the thin films. Whereas the dielectric breakdown stochastic model could predict the dielectric breakdown strength and breakdown route. After a thorough understanding of the structural-property relationship through computational materials science, in combination with the experimental verification and feedback, BiFeO3/SrTiO3 superlattice with high energy density (>100 MJ/m3) will be obtained. Last, the materials response from multi-field coupling, including external mechanical, thermal, and electric stimuli will be investigated, aiming for improving the overall robustness of the device under extreme conditions. The successful launching of this project could largely enrich the condensed matter physics theory, as well as lay the foundation for improving the properties of the electromagnetic devices such as electromagnetic gun.