Unlocking the Potential of Zintl Compounds for Thermoelectrics

第一部分：非技术性总结在NSF材料研究部固态和材料化学项目的支持下，加州大学戴维斯分校的首席研究员和她的研究小组合成并表征了新的锌化合物。锌相是由金属元素组成的化合物，但具有半导体的性质。这种材料具有潜在的优异的热电性能。价格较低的热电材料可以将废热转化为可用电力，减少我们对化石燃料的依赖，从而改变世界的能源格局。材料的能量转换效率需要像金属一样的低电阻率和像绝缘体一样的低导热系数。锌的组成和结构的独特组合可以产生优异的热电性能，通过系统地替代单个元素可以进一步优化这些性能。该项目针对高效热电材料开发了新的结构并优化了性能。在颁发该奖项期间，为研究生开发并评估了一门新课程，重点是弹性、心理健康和幸福。该项目还培训年轻的科学家在结构确定和性能测量以及热电设计和优化方面。研究生和本科生的科学和社交技能是通过研讨会、研讨会和个性化指导来发展的。第二部分：技术综述：高效热电材料是影响能源转换技术的关键。该项目在美国国家科学基金会材料研究部固态和材料化学计划的支持下，通过助熔剂和直接合成提供了新的锌相化合物，并对它们的性能进行了表征，目的是发现新的热电材料。具有良好性能的化合物将进一步优化其热电效率，为科学界提供新的研究方向。目标包括合成尚未被研究的新化合物，例如，锌相的形态优化。合成了二维(层状)和一维(链状)相，并对其性质进行了表征。通过异价和等价取代，这些新相的性能将得到提高，从而获得更好的热电性能。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，在该奖项的时间框架内教授和评估心理健康和科学复原力课程。研究生和本科生可以通过研讨会、座谈会和辅导来发展他们的科学和社交技能。这项研究将在国家会议上传播，并在同行评议的新闻上发表。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

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.