Unlocking the Potential of Zintl Compounds for Thermoelectrics

第一部分： 在NSF材料研究部门的固态和材料化学计划的支持下，加州戴维斯大学的首席研究员和她的研究小组合成并表征了新的Zintl化合物。Zintl相是由金属元素组成的化合物，但具有半导体的性质。这种类型的材料具有潜在的优异热电性能。便宜的热电材料可以通过将废热转化为可用的电力并减少我们对化石燃料的依赖来改变世界的能源格局。材料的能量转换效率需要像金属那样的低电阻率和像绝缘体那样的低热导率。Zintl相的组成和结构的独特组合可以产生特殊的热电性能，可以通过系统地替代单个元素来进一步优化。该项目开发新结构并优化性能，以实现高效热电材料。一个新的课程，研究生专注于弹性，心理健康和福祉的开发和评估在此奖项的时间。该项目还培训年轻科学家进行结构确定和性能测量沿着热电设计和优化。研究生和本科生的科学和社会技能是通过研讨会，座谈会和个性化的指导发展。 第二部分： 需要高效的热电材料来影响能量转换技术。该项目在NSF材料研究部门的固态和材料化学计划的支持下，通过通量和直接合成提供新的Zintl相化合物，并表征其性能，以发现新的热电材料。具有良好性能的化合物将进一步优化其热电效率，并为科学界提供新的研究方向。目标包括尚未研究的新化合物的合成，例如Zintl相的形态优化。二维（层状）和一维（链）包含相的合成和它们的性能表征。这些新相的性能将通过异价和等价取代而增强，从而实现更好的热电行为。研究生和本科生学习一套物理表征技术，以及如何将结构和相组成与电子和热传输特性相关联。与加州大学戴维斯分校研究生部合作，在该奖项的时间范围内教授和评估心理健康和科学弹性课程。研究生和本科生可以通过研讨会，座谈会和导师培养他们的科学和社会技能。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估来支持。

PART 1: NON-TECHNICAL SUMMARY With support from the Solid State and Materials Chemistry program in NSF’s Division of Materials Research, the principal investigator and her research group at the University of California Davis synthesize and characterize new Zintl compounds. Zintl phases are compounds composed of metallic elements but have the properties of a semiconductor. This type of material has potentially excellent thermoelectric properties. Less expensive thermoelectric materials could alter the world’s energy landscape by converting waste heat into usable electricity and reducing our dependence on fossil fuels. The energy conversion efficiency of a material requires low electrical resistivity like a metal and low thermal conductivity as in an insulator. The unique combination of composition and structure of Zintl phases can give rise to exceptional thermoelectric properties that can be further optimized by systematic substitution of individual elements. This project develops new structures and optimizes properties toward high efficiency thermoelectric materials. A new course for graduate students focused on resiliency, mental health and well-being is developed and assessed during the time of this award. This project also trains young scientists in structure determination and property measurements along with thermoelectric design and optimization. Graduate and undergraduate students’ scientific and social skills are developed through workshops, symposiums, and individualized mentoring. PART 2: TECHNICAL SUMMARY Efficient thermoelectric materials are required to impact energy conversion technologies. This project, with support from the Solid State and Materials Chemistry program in NSF’s Division of Materials Research, provides new Zintl phase compounds via flux and direct synthesis and characterizes their properties with a goal of discovering new thermoelectric materials. Compounds with promising properties are then further optimized for their thermoelectric efficiency and provide new directions of research for the scientific community. Goals include the the synthesis of new compounds that have not yet been investigated and, e.g. morphological optimization of Zintl phases. Two-dimensional (layered) and one-dimensional (chain) containing phases are synthesized and their properties characterized. The properties of these new phases will be enhanced with alio- and iso-valent substitution towards better thermoelectric behavior. Graduate and undergraduate students learn a suite of physical characterization techniques and how to correlate structure and phase composition with electronic and thermal transport properties. In collaboration with the UC Davis graduate division, a mental wellness and scientific resiliency course is taught and assessed during the timeframe of this award. Graduate and undergraduate students can develop their scientific and social skills through workshops, symposiums, and mentorship. The research will be disseminated at national meetings and findings published in peer-reviewed journals.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.