以形貌可控主族硫化物纳米晶构建热电材料的研究

Thermoelectric materials can convert waste heat into electricity and alleviate the energy crisis. Conventional thermoelectric materials that were fabricated using top-down methods suffered from several disadvantages that the starting powder was not well controlled in terms of sizes and geometrical morphology. Thereby, after sintering, the pore and grain structure was also uncontrollable. Thus, it is challenging to simultaneously maintain the performance, decrease the density and improve the portability. This project will focus on two typical thermoelectric materials, e. g. two main group metal sulfides, lead sulfide and bismuth sulfide. We attempt to construct thermoelectric materials with controllable grain and pore structures from solution-synthesized nano crystal powder that owns controllable morphology, size and composition. We will study the rules of how nano crystals grow into porous materials during sintering. The mechanism of preservation of high performance will also be investigated. The final goal is to decrease the relative density while maintain the high performance. This study will employ shape-controlled nano crystals to construct porous nano materials with decreased density, improved portability, increased surface area and enhanced diffusion of chemical species. Therefore, we envision that researchers from other fields, such as lithium ion battery, photovoltaics, catalysis and photocatalysis can be inspired.

热电材料可将废热转化为电能，从而缓解能源危机。由传统自上而下法合成的热电材料，具有起始粉末尺寸、几何形貌不可控的缺点。进一步烧结成型后孔隙和晶粒结构也不易调控，从而难以在保持性能的同时降低密度，提高其便携性。申请人将围绕硫化铅和硫化铋这两种典型的主族硫化物热电材料，期望由溶液化学合成的形貌、尺寸和组分可控的纳米晶粉末烧结构建晶粒和孔隙结构可调的热电材料。研究纳米晶烧结过程中生长为多孔材料的规律。探究此类多孔热电材料性能保持的物理机制。达到降低相对密度同时保持性能这一目标。本研究可启发研究者由形貌可控的纳米晶构建多孔纳米材料，降低材料密度、提高便携性、提高材料内表面积和促进物质扩散，从而启发其他领域的相关研究，如锂离子电池、太阳能电池、气相催化和光催化。

热电材料可将废热转化为电，从而实现减碳目标。由传统自上而下法合成的热电材料，.具有起始粉末尺寸、几何形貌不可控的缺点。进一步烧结成型后孔隙和晶粒结构也不易调控，.从而难以在保持性能的同时降低密度，提高其便携性。申请人围绕硫化铅和硫化铋这两种典.型的主族硫化物热电材料，由溶液化学合成的形貌、尺寸和组分可控的纳米晶粉末烧结构.建晶粒和孔隙结构可调的热电材料。通过透射电子显微镜和小角X射线衍射等手段.研究了纳米晶烧结过程中生长为多孔材料的规律。达到了降低相对密度同时保持性能这一目标。.本研究可启发研究者由形貌可控的纳米晶构建多孔纳米材料，降低材料密度、提高便携性、提高材料内表面.积和促进物质扩散，从而启发其他领域的相关研究，如锂离子电池、太阳能电池、气相催化和.光催化。研究成果发表于Advanced Materials, Nano Research, Journal of Alloys and Compounds 等期刊。.项目执行期间培养了2位硕士毕业生，另有8位研究生在读。