铌酸银基无铅反铁电陶瓷储能性能增强与机理研究

Energy storage materials are receiving tremendous attention and research interest due to the development of science and technology, which are at the heart of high-efficiency energy storage devices and systems. Dielectric capacitors have high power density and inferior energy density, which are irreplaceable in high energy pulse technology applications. To fulfill the emerging applications, new environmentally friendly energy storage dielectric materials with superior integrated performance that enable high energy density and power density are highly demanded. Anti-ferroelectric materials that display double hysteresis loops are receiving increasing attention for their superior energy storage density. The mainstay anti-ferroelectric materials have been the lead-based ceramics. However, the use of lead gives rise to environmental concerns, which is the drive force for soliciting alternative lead-free anti-ferroelectric energy storage materials. Recent studies have confirmed that AgNbO3 based ceramics are promising new lead-free anti-ferroelectric materials for energy storage, but its energy storage performance is still inferior to lead-based anti-ferroelectric ceramics and needs to be enhanced. Meanwhile, the mechanism for enhancing energy storage performance remains unclear. This current proposal aims to enhance the energy storage performance of AgNbO3-based ceramics by multi-doping and optimizing preparation process. The underlying mechanism for enhancing energy storage performance will be investigated. This project will provide experimental and theoretical bases for designing high-performance lead-free anti-ferroelectric energy storage ceramics.

随着科学技术的发展，储能材料因作为高效能源存储设备和系统的核心而备受关注。电介质电容器具有高功率密度和低能量密度，在高能脉冲技术中有着不可替代的应用。为满足新兴应用的需要，新型环境友好的储能电介质材料应同时兼具高能量密度和高功率密度。具有双电滞回线的反铁电材料因其高能量密度而备受关注。但目前关于反铁电储能材料的研究主要集中在铅基体系，铅的使用会引起环境问题，亟需开发无铅反铁电储能材料。近来研究发现，AgNbO3基陶瓷是一种前景广阔的新型无铅反铁电储能材料，但与铅基反铁电储能陶瓷相比，其储能性能有待进一步提高。同时AgNbO3基陶瓷储能性能增强机理尚不明晰。本项目旨在通过多元素掺杂取代及制备工艺优化，实现AgNbO3基陶瓷储能性能的提升，并探究储能性能增强机理，为高性能无铅反铁电储能陶瓷的组分和结构设计提供实验和理论依据。

电介质电容器具有高功率密度和低能量密度，在高能脉冲技术中有着不可替代的应用。为满足新兴应用的需要，新型环境友好的储能电介质材料应同时兼具高能量密度和高功率密度。AgNbO3基陶瓷是一种前景广阔的无铅反铁电储能材料，但储能性能有待进一步提高。本项目提出通过多元素掺杂取代及制备工艺优化，实现AgNbO3基陶瓷储能性能的提升。通过La/Sm/Gd/Ta/Na/Mn等元素的共同掺杂取代重点实现了AgNbO3基陶瓷反铁电稳定性的增强，其反铁电稳定性的增强主要是由相结构的变化引起的；通过优化制备工艺（水热法、轧制工艺等）重点实现了AgNbO3基陶瓷介电击穿强度的提高，其介电击穿强度的提高得益于晶粒尺寸的降低和陶瓷样品厚度的降低；进而通过设计AgNbO3基陶瓷的组分和显微结构，实现了介电击穿强度和反铁电稳定性的协同增强，制备出高性能(Ag0.91Sm0.03)(Nb0.8Ta0.2)O3多层陶瓷电容器，其Wrec为15J/cm3，ŋ为82%，Wd达到9.1J/cm3，在30-110℃的温度范围内，Wd的变化幅度小于5%，表现出良好的温度稳定性。采用脉冲激光沉积法制备AgNbO3陶瓷薄膜可以进一步降低样品厚度，得益于高介电击穿强度，AgNbO3薄膜的Wrec达到19.6J/cm3，同时发现，AgNbO3薄膜的铁电/反铁电性具有沉积温度依赖性。这些结果有望加深对AgNbO3基材料的理解，同时为AgNbO3基陶瓷的实际应用提供一定的实验基础。