压电能量收集材料中复相微结构控制及其与换能系数关联的机制研究

Based on the piezoelectric effect, piezoelectric energy harvester can capture vibration energy from the environment and convert it into electrical energy, which is a frontier in the field of new energy. The constructing of piezoelectric ceramic with both high piezoelectric strain constant and low dielectric constant is the key to obtaining the high transduction coefficient piezoelectric energy harvesting material. However, traditional strategy such as doping or complexing of multi-component solution often cause the piezoelectric strain constant and dielectric constant increase or decrease simultaneously, so it is difficult to obtain high transduction coefficient. Based on the preliminary experimental basis and materials design knowledge, it is expected that constructing novel 0-3 composite structure by introducing low dielectric and high insulating ilmenite phase into polar perovskite matrix is in favor of enhancing the transduction coefficient in a large extent. The detailed works involve developing preparation methods of ilmenite / perovskite composite material with different micro-nano structures, exploring the effects of the distribution patterns of secondary phase and shift of morphotropic phase boundary on the orientation degree of domains under strong electric field and variation trend of the dielectric constant, and ultimately seeking for the material design window of obtaining both high piezoelectric strain constant and low dielectric constant. This project could not only provide high transduction coefficient material but also supply the new constructing law of piezoelectric energy harvesting materials.

基于压电材料的正压电效应，构建从环境中捕捉振动能并转化为电能的压电能量收集器是当前新能源领域的研究前沿。合成兼具高压电应变常数与低介电常数的压电陶瓷是获取高换能系数压电能量收集材料的关键。然而，传统通过掺杂与多组元固溶复合的技术手段往往引起材料体系压电应变常数与介电常数的同增或同减，难以获取高换能系数。本项目拟基于课题组的前期实验基础与材料设计理论认知，采取将低介高绝缘的钛铁矿相引入钙钛矿铁电极性基体中构建新颖的0-3复相结构来大幅提升压电陶瓷换能系数。实验上发展不同纳微结构的钛铁矿/钙钛矿复相材料制备方法，系统研究异相分布模式和准同型相界定向迁移对复相材料强场下电畴定向程度与介电常数变化趋势的影响规律，寻找同时获得高压电应变常数与低介电常数的材料设计窗口。本项目期望不仅能够获得高换能系数材料体系，而且能为压电能量收集器材料设计提供新的技术思路与理论储备。

传统化石能源的日益短缺迫切需要拓展新能源技术以实现社会与经济的可持续发展。以压电材料为核心的压电能量收集器是新能源领域的技术前沿，有望实现环境中废弃振动能的高效采集与清洁发电。现有限制压电能量收集器发电功率提升的技术瓶颈主要是压电材料换能系数普遍偏低。结合我们已具备的研究条件、工作经验和知识积累，在国家自然科学基金项目的支持下，课题组从材料组成、工艺、结构和性能等方面深入研究了高换能系数压电能量收集复相材料设计方法与电性能提升机理，制备出多种电畴构型可控的压电能量收集材料，主要工作包括：（1）晶粒尺寸系列化PZN-PZT基压电陶瓷制备技术及能量收集特性；（2）钛铁矿化合物掺杂构建PZN-PZT基复相陶瓷及能量收集特性；（3）过渡系元素掺杂构建PZN-PZT基复相陶瓷及改性机理。本项目的创新性在于从晶体结构角度出发，提出了不同于常规掺杂与多组元固溶设计思路的全新0-3型压电能量收集复相材料设计方法，基于异质界面极化效应与掺杂取代效应的协同作用机制，实现了压电常数与介电常数变化趋势的差异化调控，这为发展实用性、高性能的新一代压电能量收集器奠定了坚实的材料设计基础。