Harvesting waste heat as electrical power: Theory-led control of heat transport in thermoelectrics

转向更清洁的能源以缓解全球变暖是我们这个时代最重要的科学和技术挑战。全球60%以上的能源被浪费在运输和工业等部门的热量中，这代表了大量不必要的温室气体排放。热电发电机通过将废热转化为电能来提高能源密集型过程的效率，因此可行的热电发电是安全、可持续能源战略的重要组成部分。尽管预计到2024年全球市场规模将达到10亿美元，但由于效率有限，以及所使用材料的稀缺性和毒性，目前大规模热电发电尚不可行。高性能热电材料需要是良好的电导体和不良的热导体。几十年来电子学的进步使材料科学家能够可靠地优化热电材料的电学特性，以提高其性能，但由于我们对热传输和如何控制它的理解不足，发展受到阻碍。这是一个材料建模的领域-使用理论和高性能计算计算和分析材料特性-已被证明是非常成功的。由该奖学金开创的研究项目将跨越物理学、材料科学和化学之间的界限，开发建模工具，以更全面地理解和控制材料中的热传输，特别是热电学。这将通过三个互补的目标来实现：(1)提高我们对掺杂和合金化（两种广泛用于优化热电性能的工程策略）如何影响热传递的理解。这将允许建立一套设计规则，以选择最佳的材料修改，以优化热传输与电性能，允许有针对性地改进新的和现有的旗舰热电材料。(2)解释在一些性能最高的热电材料中发现的复杂（“非调和”）结构动力学是如何导致其理想的超低热输运的，并制定“设计”这种行为的策略，作为与现有策略一起提高热电性能的新途径。(3)基于传统无机小分子材料开发新型高性能热电材料。这些“混合”材料因其在高性能太阳能电池中的潜在用途而成为头条新闻，并且最近被证明具有异常低的导热性，这表明类似材料可能是热电材料的良好候选材料。因此，最后一个目标将建立在前两个目标中开发的工具和洞察力的基础上，以识别和开发这些材料，使其成为下一代高性能热电材料。这项研究将建立新的路线，以提高当前和未来的热电材料的性能，并将证明理论主导的设计一类新的高效，具有成本效益和可持续的热电材料适合广泛的商业化。它将使英国处于热电研究的前沿，为关键的全球挑战提供及时的解决方案，并从不断增长的全球市场中受益。这一项目提高了控制热传输的能力，也将对其他技术产生直接的好处，产生更高效的太阳能电池，更好的电池热管理，以及改进的电力电子和硅芯片等。

Switching to cleaner sources of energy to alleviate global warming is the most important scientific and technological challenge of our time. More than 60 % of the energy used worldwide is wasted as heat from sectors including transportation and industry, representing vast quantities of unnecessary greenhouse gas emissions. Thermoelectric generators improve the efficiency of energy-intensive processes by recovering waste heat as electricity, and viable thermoelectric power is therefore an important part of a secure, sustainable energy strategy. Despite a projected global market of $1bn by 2024, however, large-scale thermoelectric power is currently not feasible due to limited efficiency and the scarcity and toxicity of the materials used.High-performance thermoelectric materials need to be good conductors of electricity and poor conductors of heat. Decades of advances in electronics have enabled materials scientists to reliably optimise the electrical properties of thermoelectrics to improve their performance, but developments are being held back by our poor understanding of heat transport and how to control it. This is an area where materials modelling - calculating and analysing material properties using theory and high-performance computing - has proven to be very successful.The research programme pioneered by this fellowship will cross the boundaries between physics, materials science and chemistry to develop the modelling tools needed for more complete understanding and control of heat transport in materials in general and thermoelectrics in particular. This will be achieved through three complementary aims:(1) Improving our understanding of how doping and alloying - both engineering strategies widely used to optimise thermoelectric performance - affect heat transport. This will allow a set of design rules to be established for choosing the best material modifications to optimise heat transport in tandem with electrical properties, allowing for targeted improvement of new and existing flagship thermoelectric materials. (2) Explaining how the complex ("anharmonic") structural dynamics found in some of the highest-performing thermoelectric materials leads to their desirable ultra-low heat transport, and developing strategies to "design in" this behaviour as a new route to improve thermoelectric performance alongside existing strategies.(3) Developing a novel class of high-performance thermoelectrics based on traditional inorganic materials incorporating small molecules. These "hybrid" materials made headlines for their potential use in high-performance solar cells, and have very recently been shown to have unusually low thermal conductivity, indicating that similar materials may be good candidate thermoelectrics. This last aim will therefore build on the tools and insight developed within the first two to identify and develop these materials into the next generation of high-performance thermoelectrics.This research will establish new routes to improve the performance of current and future thermoelectric materials and will demonstrate the theory-led design of a new class of efficient, cost-effective and sustainable thermoelectric materials suitable for widespread commercialisation. It will put the UK at the forefront of thermoelectric research to provide timely solutions to a critical worldwide challenge and benefit from a growing global market. An improved ability to control heat transport enabled by this programme will also be of immediate benefit to other technologies, yielding more efficient solar cells, better thermal management in batteries and improved power electronics and silicon chips, among others.