Synthesis and Characterization of New Zintl Phases for Thermoelectric Applications

先进材料的发展被广泛认为是新兴技术背后的关键因素之一，这些技术可以实现可持续的环境，并为我们的星球提供充足的清洁能源。该建议的重点是合成和表征Zintl相与热电应用的潜力。Zintl相是一类已经显示出重大前景的化合物，通过使用这些材料制造的设备的效率加倍来改变能量转换的前景。这一提议对下一代科学家的培训产生了更广泛的影响，使他们能够在未来几十年内解决转化材料的需求。该提案支持处于初级阶段的少数民族和妇女（高中到大学（ACS SEED方案）和大学到研究生院（数学和物理科学本科研究参与者导师，MURPPS）），沿着培训研究生从事科学职业。学生与喷气推进实验室的科学家合作，了解和提高材料的效率，并有望用于热电应用。学生通过实践培训，探索和向更广泛的科学界传播研究来培养科学，社会和专业技能。材料合成和结构-性能相关性的基础培训为热能到电能转换的发展和与技术相一致的多学科研究的进步提供了重要基础。该研究将在国家和国际会议上发表，研究结果将发表在同行评审期刊上。技术概要：热电材料将热量直接转化为电能，反之亦然。在材料研究部门的固态和材料化学计划的支持下，该项目专注于合成新的Zintl相，将过渡金属和地球丰富的元素结合在一起，以在费米能级（通过部分填充的d轨道）实现高态密度（DOS），从而获得高Seebeck效应（功率因数）和高zT。相将通过熔剂、冶金路线和放电等离子烧结合成为单晶、高纯度粉末和颗粒。利用一套物理表征技术，包括单晶和粉末X射线衍射，扫描电镜，元素波色散微探针，平行的电和磁测量，结构和相组成将与电子和热输运性质。该项目的最终目标是发现具有高zT的新材料，用于将废热直接转化为电能。基于最近的结果，证明高zT在Zintl阶段，该建议密切联系的合成策略与表征的物理和化学性质，从而提供有效的反馈，以指导这些热电系统的改进。

NON-TECHNICAL SUMMARY:The development of advanced materials is widely recognized as one of the key elements behind emerging technologies that can potentially achieve a sustainable environment and provide adequate, clean energy for our planet. This proposal is focused on the synthesis and characterization of Zintl phases with potential for thermoelectric applications. Zintl phases are a class of compounds that have already shown significant promise, changing the landscape of energy conversion by doubling the efficiencies of devices made with these materials. This proposal has broader impacts associated with training of the next generation of scientists, enabling them to tackle transforming materials needs over the next several decades. This proposal supports minorities and women at the initial stages (high school to college (ACS SEED program) and college to graduate school (Mentorships for Undergraduate Research Participants in Mathematical and Physical Sciences, MURPPS), along with training graduate students for scientific careers. Students collaborate with scientists at the Jet Propulsion Laboratory to understand and enhance the efficiencies for materials with promise for thermoelectric applications. Students develop scientific, social, and professional skills through hands-on training, exploration, and dissemination of research to the broader scientific community. Fundamental training in materials synthesis and structure-property correlations provides an important foundation for the development of thermal to electrical energy conversion and the advancement of multidisciplinary research aligned with technology. The research will be presented at national and international meetings and the findings published in peer-review journals.TECHNICAL SUMMARY:Thermoelectric materials convert heat directly into electricity or vice versa. With support of the Solid State and Materials Chemistry program in the Division of Materials Research, this project focuses on the synthesis of new Zintl phases, incorporating transition metals and earth abundant elements in order to target a high density of states (DOS) at the Fermi level (through partially filled d orbitals) to obtain high Seebeck effect (Power factor) and therefore high zT. Phases will be synthesized as single crystals, high purity powders and pellets via flux, metallurgical routes, and spark plasma sintering. Utilizing a suite of physical characterization techniques including single crystal and powder X-ray diffraction, SEM, elemental wave dispersive microprobe, parallel electrical and magnetic measurements, the structure and phase composition will be correlated with electronic and thermal transport properties. The ultimate goal of this project is to discover new materials with high zT for the direct conversion of waste heat into electricity. Building upon recent results of demonstrated high zT in Zintl phases, this proposal closely links synthetic strategies with characterization of physical and chemical properties, thus providing efficient feedback to guide improvement of these thermoelectric systems.