Engineering of Carbon-Oxide Composite Thermoelectric Nanomaterials

对碳排放的日益关注促使了包括热电（TE）在内的替代、更环保和可持续技术的发展。TE器件是将热能转化为电能的固态能量转换器，适用于交通、核能、制造业等发电行业。传统TE材料的一个限制是，要达到最大性能，温度范围非常窄，Bi2Te3低至50℃，功率输出有限，效率相对较低，成本和环境问题，因为毒性。如果要经济可靠地使用TE技术，则材料需要在更宽的温度窗内表现出高的TE效率。氧化物，如钛酸钙钛矿，由于其灵活的结构和高温稳定性，是有前途的TE材料；它们目前的限制是效率不高。然而，通过纳米尺度的纳米结构和能带工程，氧化物TEs和碳纳米技术的集成具有提高性能的前景。我们的研究愿景是通过将TE和碳纳米技术整合到氧化物的微观结构中，以碳（石墨烯）或碳化物的形式增强氧化物的热电性能；这将产生碳氧化物复合材料，并扩大工作温度范围。然而，这些复合材料的工程化只有在我们对降低导热性所需的纳米结构和提高导电性所需的界面结构和成分进行表征和控制的情况下才能实现。我们的方法包括实验和建模，以实现以下目标：(1)制造基于SrTiO3， TiO2的热电碳氧化物复合材料，具有一系列纳米结构，以确定控制电和热输运的因素；(2)识别导致性能增强的氧化物与碳之间的相互作用；(3)建立目标微观结构的原子模型，并表征其稳定性、拓扑结构、组成和电子结构。该提案是与曼彻斯特大学和巴斯大学合作的一部分。它是新颖和及时的，因为利用多学科方法（建模/实验）开发新的材料加工策略来研究廉价和可持续能源发电的新兴技术。英国需要走在这一领域的前沿，因为日本、美国和欧洲确实有主要的TE项目。工作计划包括(1)目标材料：SrTiO3， TiO2陶瓷，(2)材料加工，(3)氧化石墨烯（即La/SrTiO3与石墨烯）和氧化碳化物（TiC1-xOx/TiOy）复合材料的微观结构控制，(4)常规XRD和SEM的一般表征，(5)热电参数的测量，(6)界面和纳米结构的作用和生成表征。

The growing concern over carbon emissions has led the development of alternative, greener and sustainable technologies including thermoelectrics (TE). TE devices are solid-state energy converters that transform thermal energy into electricity, applicable to power generation including transportation, nuclear, and manufacturing industries. A limitation of traditional TE materials is the very narrow temperature range for maximum performance, as low as 50C for Bi2Te3, limited power output, relatively low efficiency, the cost and environmental concerns due to toxicity. If TE technology is to be used economically and reliably, the materials need to exhibit high TE efficiency over a wider temperature window. Oxides, e.g. titanate perovskites, are promising TE materials because of their flexible structure and high temperature stability; their current limitations are the modest efficiency. However, integration of oxide TEs and carbon nanotechnologies has the prospect of enhancing performance, via nanostructuring and band engineering at the nanoscale. Our research vision is to enhance thermoelectric properties of oxides by integrating TE and carbon nanotechnologies, as either carbon (graphene) or carbide, into the oxide microstructure; this will generate carbon-oxide composites and extend the range of operating temperatures. However, the engineering of these composites can only be achieved if we characterize and control both the nanostructuring needed for reduced thermal conductivity, and the interface structures and compositions needed for increased electrical conductivity. Our approach involves experiments and modelling to achieve the following objectives: (1) to fabricate thermoelectrics carbon-oxide composites based on SrTiO3, TiO2, with a range of nanostructures to determine the factors controlling electric and thermal transport; (2) to identify the interactions between oxides and carbon that lead to enhanced performance; (3) to produce atomistic models of target microstructures, and to characterize their stability, topology, composition and electronic structure. This proposal is part of a collaboration with the University of Manchester and Bath. It is novel and timely because exploits novel material processing strategies using a multidisciplinary approach (modelling/experiments) to study emerging technologies for cheap and sustainable energy generation. The UK needs to be at the forefront of this field as there are indeed major programmes in TE in Japan, USA, and Europe.The work programme covers (1) target materials: SrTiO3, TiO2 ceramics, (2) materials processing, (3) microstructural control of oxide-graphene (i.e. La/SrTiO3 with graphene) and oxide-carbide (TiC1-xOx/TiOy) composites, (4) general characterization with routine XRD and SEM, (5) measurements of thermoelectric parameters, (6) characterization of the role and generation of interfaces and nanostructures.