热电耦合下陶瓷的热释电效应及能量收集研究

Converting the widely existing waste heat into electric energy makes energy recycled and has great potential application in power-supply of wearable devices and wireless sensor network nodes, which makes energy harvesting based on pyroelectric materials a hot research topic in the field of micro-energy. However, the current pyroelectric energy harvester has poor heat transfer and low output electrical energy, which seriously limits their practical application. In view of the above problems, this project creatively proceeds from both "heat" and "electricity". From the "heat" point of view, the thermal conductive network was constructed in the pyroelectric ceramic and thereby fundamentally improved the thermal response between ceramic grains. From the point of view of "electricity", mesoporous structure was introduced into the grain to reduce the dielectric constant of ceramics, improve figure of merits and thus obtain high output energy. In addition, the strong thermal-electric coupling effect of the ceramic with composite structure was ensured, and the fabrication of the high-efficiency pyroelectric energy harvesters was realized. This project provides a new idea for the study of thermo-electric coupling mechanism of traditional pyroelectric ceramics, opens up a new way to effectively improve the energy conversion of traditional pyroelectric energy harvesters, and has important significance for promoting the application and development of pyroelectric energy harvesters.

将生活中广泛存在的废热转化为电能，使得能源得到循环利用，在可穿戴设备和无线传感网络节点等供电领域有极大的应用潜力，使得基于热释电材料的能量收集成为微能量领域的研究热点。然而，现有的热释电能量收集器热传递差、输出能量低，这严重限制其在实际中的应用。针对上述问题，本项目创造性地从“热”与“电”两方面着手：从“热”的角度出发，在热释电陶瓷基体内构建热传导网络，从根本上提高陶瓷晶粒之间的热响应；从“电”的角度出发，在晶粒内部引入介孔结构，以降低陶瓷的介电常数，提高其能量优值，获得高输出能量。进而保证陶瓷复合结构的强“热”-“电”耦合效应，实现高效热释电能量收集器的制备。本项目为传统热释电陶瓷的热电耦合机制的研究提供了全新思路，为有效提升传统热释电能量收集器的换能效果开辟了全新途径，并对推动热释电能量收集器的应用与发展有重要意义。

热传递差、输出能量低是限制热释电能量收集器推广应用的主要问题。针对这些问题，申请人在前期研究工作的基础上，一方面通过高热导添加剂ZnO提高热释电材料的热导，研究了添加剂对陶瓷热导、热释电系数、温度随时间的变化率(dT/dt)以及输出能量的影响；通过PFM分析了ZnO在微区对压电响应和温度变化的影响，进一步通过能量收集结果显示，ZnO可有效提高陶瓷的输出能量；另一方面，从晶体的介孔入手，研究了添加剂多壁碳纳米管（CNTs）和PMMA对陶瓷孔隙率和对陶瓷热释电系数、介电常数、能量优值及输出能量的影响，通过PFM分析了CNTs 和PMMA在微区对压电响应和温度变化的影响，研究了对能量优值和输出能量的影响。结果显示，选择合适的CNTs和PMMA可有效提高能量优值和输出能量。本项目的研究为热释电能量收集器的热电耦合机制提供了全新的思路，为提升热释电能量收集器的输出能量提供了全新途径，对热释电能量收集器的推广应用有重要意义。.项目资助发表中科院1区文章一篇，四区文章2篇，待发表3篇。特邀报告1次，口头报告1次。项目投入经费25万元，支出17.3881万元，结余7.6419万元。剩余经费用于本项目的后续研究支出。