CFRC-Seebeck效应的多类型界面散射强化机理与方法研究

Carbon fiber reinforced cement-based composites (CFRC) with high Seebeck coefficient are of considerable promise on mass energy harvesting, heating snow removal by low energy consumption and structural health monitoring sensors. Their Seebeck coefficient and thermoelectric conversion efficiency have to increase before them came into spread use. However, the enhanced mechanism and method of CFRC-Seebeck effect remain elusive. Since owning the intrinsic microscopic defects with high density, the enhanced mechanism of CFRC-Seebeck effect differs obviously from that of crystalline materials. The interrelated theories about strengthening of CFRC-Seebeck effect have also not been reported at home and abroad. Strengthening action of the interface between metal oxide micro/nano-particles and cement matrix has been found in our previous work, and the electrical conductivity of CFRC grow simultaneously. Based on it, in this project multi-type interfaces emerged by intrinsic microscopic defects of CFRC will be characterized quantificationally. The influences of the interface type, interface structure and distribution density on carrier scattering and Seebeck effect will be researched. Then, the strengthening mechanism of CFRC-Seebeck effect by the multi-type interfaces scattering can be explained. The evaluation method of CFRC-Seebeck effect is also established by taking advantage of materials processing, and the scattering intensity divergence and cooperation between the multi-type interfaces. The research results will provide a new way to elevate the efficiency of energy utilization.

高Seebeck系数碳纤维水泥基复合材料（CFRC）在规模化能量转换收集，道路低能耗热融除雪和建筑健康监测传感器领域有重要应用。提高Seebeck系数与能量转化效率是其应用的前提，而确切的强化机理与方法尚未阐明。CFRC具有的高密度本征微观结构缺陷使其Seebeck效应强化机制与晶态材料有明显差异，有关CFRC-Seebeck效应强化的相关理论，迄今国内外也尚未报道。本课题前期研究发现微/纳米金属氧化物与水泥基体的界面可显著增强CFRC-Seebeck效应并提高电导率。在此基础上，本课题将定量化表征CFRC微观结构缺陷产生的多类型界面，研究界面类型、结构与分布对载流子散射和Seebeck效应的影响规律，阐明CFRC-Seebeck效应的多类型界面散射强化机理，并利用复合材料工艺和界面类型的散射强度差异与协同作用，获得CFRC-Seebeck效应的强化方法，为促进能源高效利用提供一种新途径。

高 Seebeck 系数碳纤维水泥基复合材料（CFRC）在规模化能量转换收集，道路低能耗热融除雪和建筑健康监测传感器领域有重要应用。本项目采用激光共聚焦显微镜、扫描电镜、体视学分析、霍尔系数测量等方法，通过控制金属氧化物/基体界面密度、气/固界面密度、孔隙率、构造碳界面层等途径，定量化表征 CFRC 微观结构缺陷产生的多类型界面，建立了界面参数特征与CFRC-Seebeck系数和电导率之间的数学关系，以及对载流子输运的影响规律。主要研究结果有：（1）CFRC密实度增加，材料单位体积碳含量增加，气/固界面密度降低，CFRC综合热电性能增强；（2）CFRC-Seebeck系数绝对值与气孔率呈正比例关系，CFRC电导率与气孔率呈反比例关系；（3）CFRC碳含量增加，Seebeck系数稳定较好，电导率显著增加；（4）适当增加金属氧化物/水泥基体界面密度，有利于CFRC电导率和Seebeck系数的强化；（5）细化水泥粉体粒度，增加水化产物间界面密度，可使CFRC电导率提高；（6）碳纤维表面涂层处理，构造具有不同粗糙度碳界面层，可使材料载流子浓度增加，优化电导率和功率因数；（7）铜纤维的加入可以显著提高CFRC电导率，提高小温差条件下热电势，CFRC综合热电性能得到改善；（8）水分可通过CFRC中离子行为影响其热电性能；适当增加材料增加含水率，Seebeck效应得到强化；（9）垂直于热流方向的气/固界面，通过载流子散射作用强化Seebeck效应；（10）CFRC中材料载流子浓度和迁移率，均与膨胀石墨含量存在线性正比例函数关系。通过上述结果，阐明了CFRC-Seebeck 效应的多类型界面散射强化机理，获得了CFRC-Seebeck 效应的强化方法。本项目研究结果为促进建筑领域的能源高效利用提供一种新途径。

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