Synthesis of Zintl Phases for Thermoelectric Applications

用于热电应用的 Zintl 相的合成

• 批准号: 1100313
• 负责人: Susan Kauzlarich
• 金额: $ 50万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-04-01 至 2015-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1100313&HistoricalAwards=false
• 关键词: Synthesis; Zintl; Phases; Thermoelectric; Applications

TECHNICAL SUMMARY: This project, supported by the Solid State and Materials Chemistry program focuses on the synthesis of new Zintl phases, incorporating transition metals in order to target a high density of states (DOS) at the Fermi level (through partially filled d orbitals) to obtain high Seebeck coefficient (Power factor) and therefore high zT. Nanostructuring will be employed to further reduce the thermal conductivity. Phases will be synthesized via flux and metallurgical routes. Utilizing a suite of physical characterization techniques including single crystal and powder X-ray diffraction, SEM and TEM, elemental wave dispersive microprobe and ICP-MS analysis, parallel electrical and magnetic measurements, the structure and phase composition will be correlated with electronic and thermal transport properties. The ultimate goal of the 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.NON-TECHNICAL SUMMARY: Thermoelectric devices for power generation convert thermal energy directly into electrical energy, require minimal maintenance, and can be operated over a large temperature range (room temperature to 1000 degrees C). Thermoelectric materials are described by a figure of merit, zT, which relates to how well a material converts heat flow to electricity - the higher the value, the greater the efficiency. Recent discoveries of Zintl phases with zT of 1.0 or greater highlight the importance of continued exploration of new materials. A Zintl phase is a compound which contains both cations such as alkali, alkaline earth, and rare earth elements which donate electrons to polyanionic units composed of main group elements such as those from groups 13, 14, and 15 of the periodic table. These types of compounds naturally provide low thermal conductivity which is a requirement for thermoelectric devices. With higher zT, the potential for solid-state power generation from waste heat recovery provides a framework for investigating new Zintl phase materials with stability and optimal properties at high temperatures (300 degrees C). This project supports minorities and women at the initial stages (high school to college and college to graduate school), along with training graduate student for scientific careers. Students develop scientific, social, and professional skills through hands-on training, exploration, and dissemination of research to the broader scientific community. The topics under study include materials synthesis and property measurements, fundamental training in materials synthesis and structure-property correlations, providing 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. Additionally, the PI supports students through the ACS SEED program (high school), MURPPS (undergraduate), and AGEP (graduate) programs focused on increasing underrepresented groups in science on campus. The ChemWiki will be employed to enhance student learning through writing and critical evaluation.

技术摘要：在固态和材料化学计划的支持下，该项目着重于新的Zintl阶段的综合，并结合过渡金属，以针对费米级（通过部分填充的D轨道）（通过部分填充的D轨道）靶向高密度状态（DOS），以获得高的SEEBECK系数（功率系数），从而获得高ZT。纳米结构将用于进一步降低导热率。相位将通过通量和冶金路线合成。利用一套物理表征技术，包括单晶和粉末X射线衍射，SEM和TEM，元素波分散微探针以及ICP-MS分析，平行电气和磁性测量，结构和相组成将与电子和热运输特性相关。该项目的最终目标是发现具有高ZT的新材料，以将废热直接转换为电力。 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.NON-TECHNICAL SUMMARY: Thermoelectric devices for power generation convert thermal energy directly into electrical energy, require minimal maintenance, and can be operated over a large temperature range (room temperature to 1000 degrees C).热电材料通过功绩ZT的图来描述，该图与材料将热流转换为电的程度有关 - 值越高，效率就越大。 ZINTL阶段的最新发现ZT为1.0或更高，突出了持续探索新材料的重要性。 ZINTL相是一种化合物，其中包含两个阳离子，例如碱，碱土和稀土元素，它们将电子捐赠给由主要组元素组成的聚元素单位，例如元素性表的第13、14和15组。这些类型的化合物自然提供低导热率，这是热电设备的要求。具有较高的ZT，从废热恢复中产生固态发电的可能性为研究具有稳定性和最佳特性的新Zintl相材料（300摄氏度）提供了框架。该项目在最初的阶段（高中至大学，大学到研究生院）以及科学职业的培训研究生。学生通过动手培训，探索和向更广泛的科学界进行研究来发展科学，社会和专业技能。研究的主题包括材料合成和财产测量，材料合成的基本培训和结构 - 质体相关性，为电能转化到电能转化的发展提供了重要的基础，以及与技术保持一致的多学科研究的进步。这项研究将在国家和国际会议以及在同行评审期刊上发表的调查结果中介绍。此外，PI通过ACS种子计划（高中），MURPPS（本科）和AGEP（研究生）计划为学生提供支持，该计划致力于增加校园科学中代表性不足的群体。 Chemwiki将被用来通过写作和批判性评估来增强学生的学习。