利用界面工程开发高性能碲化亚锡基热电材料

In recent years, high performance thermoelectric materials have drawn great research attentions as one of sustainable solutions to tackle the global energy shortage and environmental pollution that were caused by the exhaust of fossil fuels. Thermoelectric materials can directly convert industrial waste heat into electricity; however, their relatively low efficiency and high cost limited their applications. In this proposal, the development of high performance, low cost Tin Telluride-based thermoelectric materials is focused to promote the practical applications of intermediate temperature thermoelectrics. Tin Telluride is an environmental friendly thermoelectric candidate with intrinsically high carrier concentration and high thermal conductivity, which are harmful to their thermoelectric performance. To address this issue, herein, a creative “low entropy grain-high entropy interface” strategy is proposed, which involves nanostructure engineering and interface engineering. In this research, the surface of solvothermal synthesized Tin Telluride will be modified via chemical deposition, followed by a fast Spark Plasma Sintering process. By varying the reaction conditions of solvothermal synthesis and chemical deposition, the grain size, the density of grain boundaries, and the interfacial microstructures of our products can be well-controlled. The merit of this strategy is to keep the grains of Tin Telluride un-doped to avoid over-developed carrier concentration or carrier scattering via point defects; but to create modified interfaces with complex microstructures, so that the low energy charge carriers can be filtered by the interfaces as well as phonons, resulting in improved electrical and thermal transport properties. The key of this research is to study the underlying mechanisms of how the interfacial microstructures will affect the thermoelectric performance and mechanical properties of Tin Telluride, and to establish a systemic understanding of the structure-property interaction in Tin Telluride-based thermoelectric materials. Ultimately, the overall thermoelectric performance of Tin Telluride is expected to be significantly enhanced by facile and low cost procedures, so that Tin Telluride can be realized a competitive thermoelectric candidate. This research shall provide solid experimental and theoretical guidance on developing high performance thermoelectric materials.

为缓解化石燃料急剧消耗带来的能源短缺和环境污染等问题，本项目致力于开发高性能、低成本和环境友好的碲化亚锡基中温区热电材料，为其大规模应用于回收工业废热直接发电提供可能性。针对碲化亚锡本征载流子浓度较高、热导率偏高等缺点，本项目拟沿着“晶粒内部素化-界面处高熵”的全新解决思路，利用溶剂热法合成纳米尺度的碲化亚锡，并用化学沉积法对其表面进行修饰，结合放电等离子快速烧结手段，在材料中引入高度可控的修饰晶界而保持晶粒内部的纯化，避免引入过多点缺陷而限制材料电性能提升。并拟以材料纳米化和界面修饰为切入点，建立材料界面微结构控制与其热电性能调控的关联，阐述材料微观结构和界面修饰对其热电参数的作用规律、内在机理和它们之间的构效关系，以及材料界面微结构调控对材料的机械性能和加工性能的影响。本项目有望实现碲化亚锡基材料在总体热电性能上的显著突破，为高性能热电材料的制备和改良奠定坚实的实验指导和理论基础。

为缓解化石燃料急剧消耗带来的能源短缺和环境污染等问题，本项目致力于开发高性能、 低成本和环境友好的SnTe基中温区热电材料，为其大规模应用于回收工业废热直接发电提 供可能性。针对SnTe本征载流子浓度较高、热导率偏高等缺点，本项目提出“晶粒内部素化-界面处高熵”的全新解决思路，利用溶剂热法合成尺度可控的SnTe，以调控烧结后材料的界面浓度，并用化学法对其表面分别进行了Ag、MXene和Sb2Te3的修饰，结合放电等离子快速烧结手段，在材料中引入可控的修饰晶界而保持晶粒内部的纯化，避免引入过多点缺陷而限制材料电性能提升。研究结果显示Ag修饰SnTn界面能起到Ag掺杂和引入Ag/SnTe界面的双重功效，对材料的电、热输运性能起到调控作用，显著提升了材料的热电优值。二维MXene材料和SnTe基体的相互作用能在一定程度上抑制Sn空位的产生，同时强烈散射声子，降低材料热导率而提升热电优值。Sb2Te3在烧结后会与SnTe基体发生离子交换反应，在SnTe颗粒间重结晶生成纳米级SnSb和SnTe颗粒，还会引入Sb掺杂，使电和热性能协同改善，热电优值最大能增加一倍。.本项目以材料纳米化和界面修饰为切入点，建立了材料界面微结构控制与其热电性能调控的关联，阐述了材料微观结构和界面修饰对其热电参数的作用规律、内在机理和它们之间的构效关系，以及材料界面微结构调控对材料的机械性能和加工性能的影响。实现了碲化亚锡基材料在总体热电性能上的显著突破，为高性能热电材料的制备和改良奠定坚实的实验指导和理论基础。.