新型Ba(Cu0.5W0.5)O3基巨介电陶瓷的组成设计、点缺陷及储能特性研究

Study of giant dielectric materials have become an interesting topic as energy storage devices. However, the low breakdown field strength and the high loss limit its progress. In this project, based on component and binary system design of novel Ba(Cu0.5W0.5)O3 based colossal dielectric ceramics using via solid-state reaction and hydrothermal method. The relation between microstructure and dielectric properties、energy storage performance will be studied systematically. By investigating and exploring the influence of the microstructure and defects on dielectric properties and energy storage performance in Ba(Cu0.5W0.5)O3 based materials, the correlations among preparation method, point defects, dielectric properties and energy storage performance will be revealed. This study could not only provide an insight into the physical mechanisms of Ba(Cu0.5W0.5)O3 materials, but also could help us to accurately predict and determine the electrical properties of Ba(Cu0.5W0.5)O3 based materials. Furthermore, it may be unified physical mechanisms for the huge dielectric materials with high dielectric constant, low dielectric loss and relatively high energy storage performance used. The study also shows a great importance for preparing and improving electrical properties of other dielectric ceramics. The micro mechanism of giant dielectric response of Ba(Cu0.5W0.5)O3 ceramics was revealed or enriching and improving theory and model of the ACu3Ti4O12 (ACTO) and (In, Nb) co-doping TiO2 giant dielectric ceramics. This study will provide new high-performance materials with giant dielectric properties, high energy storage performance and dielectric low loss for the solid super-capacitor.

高介电常数材料的开发已成为当前储能电容器的研究热点。围绕高击穿场强和低介电损耗缺乏科学预见以及巨介电响应机理不甚明晰等问题，本项目基于组成设计和引入第二组元调控Ba(Cu0.5W0.5)O3基陶瓷，拟开展水热法制备Ba(Cu0.5W0.5)O3基材料微观形貌、介电性能及储能特性的研究工作。构筑不同微结构钨铜酸钡纳米粉体，探究陶瓷的微观结构和性能的关联性；研究化学计量、气氛烧结与退火等工艺条件对材料结构、显微组织与宏观电学性能的影响；采用X射线漫散射、HTEM、EPR等技术对材料中的点缺陷进行表征， 揭示制备方法、点缺陷与介电常数、储能性能之间的关联性，阐明巨介电响应的物理机制，提出Ba(Cu0.5W0.5)O3基陶瓷微结构调控介电性能和储能特性的基本原则。本研究将为ACu3Ti4O12、TiO2基巨介电陶瓷在高容量电容器和储能领域的应用奠定基础，并丰富电介质理论。

项目针对目前高介电陶瓷偏压性能差、击穿电压低及介电损耗高的不足，合成新型Ba(Cu1/2W1/2)O3(BCWO)基巨介电材料，并探讨合成、相结构、微观结构和介电响应之间的关系。首先，用固相法合成了不同形貌的BCWO陶瓷材料，探讨了性能-结构之间的关系，系统研究了不同取代离子引起的点缺陷对晶体结构、微观形貌（晶粒、晶界及电畴等）及巨介电性能的内在联系。研究发现：固相法950℃下烧结的BCWO基陶瓷粉末呈现钙钛矿结构，巨介电性能达到104以上。其次，调节固相法制备工艺来获得高介电常数、低介电损耗、介电常数温度及频率稳定性综合性能优良的BCWO材料以系统探讨材料产生巨介电性的物理机制；通过B位离子（Mn3+/Mn4+）取代进一步优化材料介电性能，特别是材料低频介电损耗，研究离子取代对材料介电性能，显微结构，相结构的影响规律，选择出最佳材料组分，系统分析并阐明材料宏观介电性能与微观结构，晶界及晶粒电性能之间的相互关联性。最后，深入探讨了变价B位离子的Ba(W1/2Cu1/2)1-xMnxO3（BWCMO）基材料高温介电弛豫物理机制，并在前期研究的基础上，采用溶胶-凝胶法制备BWCO陶瓷，系统研究了不同溶胶-凝胶前驱条件对BWCO陶瓷粉体XRD、微观形貌和介电性能的影响。最佳溶胶-凝胶前驱条件为：peg+柠檬酸是最优表面活性剂组成，加入peg和柠檬酸的钨铜酸钡材料，表面形貌清楚，介电性能最好。本项目的开展对于结构陶瓷的制备及电学性能和储能特性的调控和微电子元器件向高储能、小型化和高速化的进一步发展具有非常重要的理论意义和应用价值。目前发表已收录SCI论文5篇(标注），获授权专利1项，在公示期内专利2项。正在培养硕士生1名，毕业本科生4名。