Ultra-high temperature synthesis of high-performance Zintl thermoelectrics

能够有效利用能源的技术可能对当今最紧迫的问题产生巨大影响：全球变暖和对日益减少的化石燃料供应的依赖。拟议的研究通过研究下一代热电材料来解决这一主题挑战，这种材料可以收集废热并将其转化为有用的电能。特别是，研究重点是可以在高温下工作的热电材料，这是必不可少的，因为卡诺效率（热力学最大值）随着温差的增加而增加。科学挑战是优化三个相互竞争的材料参数；塞贝克电压；具有良好的导电性和导热性，并能在具有良好温度稳定性的材料中做到这一点。该研究的新颖之处在于使用超高温合成来实现温度稳定性，并在纳米复合材料中协同利用Zintl化学和界面来获得大的热电值。Zintl相是关键的高性能热电材料，因为与电子均质材料相比，离子和共价区域的同时存在使热电参数更加独立优化。已经确定了两类有前途的zintl型相，并且通过在纳米复合材料中使用界面，将进一步提高优秀块体材料的性能。这项雄心勃勃的变革性研究计划将有助于开发在最适合发电的温度下工作的高性能热电材料，实现20-30%的能量转换效率。这项研究还将导致对成分、结构和热电性能之间关系的进一步了解。

Technologies that enable the efficient use of energy could have an enormous impact on the most pressing issues of today: global warming and the reliance on ever-dwindling supplies of fossil fuels.The proposed research addresses this topical challenge through the investigation of the next generation of thermoelectric materials that harvest waste heat and transform it into useful electricity. In particular, the research is focused on thermoelectric materials that can operate at high temperatures, which is essential as the Carnot efficiency (the thermodynamic maximum) increases with temperature difference.The scientific challenge is to optimise three competing material parameters; the Seebeck voltage; the electrical and thermal conductivity, and to do this in a material with good temperature stability.The novelty of the proposed research derives from the use of ultra-high temperature synthesis to achieve temperature stability, and the synergistic exploitation of Zintl chemistry and interfaces in nanocomposites to obtain large thermoelectric figures of merit.Zintl phases are key high-performance thermoelectric materials because the simultaneous presence of ionic and covalent regions enables a more independent optimisation of the thermoelectric parameters compared to electronically homogeneous materials. Two classes of promising Zintl-type phases have been identified, and the performance of outstanding bulk materials will be further enhanced through the use of interfaces in nanocomposites.This ambitious and transformative research programme will contribute towards the development of high-performance thermoelectric materials operating at temperatures most suitable to power generation, enabling 20-30% energy conversion efficiencies. The research will also lead to an increased understanding of the relation between composition, structure and thermoelectric properties.