Enhanced thermoelectric properties of carbon fiber reinforced cement composites
Enhanced thermoelectric properties of carbon fiber reinforced cement composites
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DOI：
10.1016/j.ceramint.2016.04.014
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发表时间：
2016-08
影响因子：
5.2
通讯作者：
Jiangxiong Wei;Z. Qian;Lili Zhao;L. Hao;Chunli Yang
中科院分区：
文献类型：
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作者：
Jiangxiong Wei;Z. Qian;Lili Zhao;L. Hao;Chunli Yang
碳纤维增强水泥基复合材料（CFRCs）的热电性能近年来引起了相关的兴趣，这是由于其在城市地区和道路中收集环境能量的迷人能力，以及水泥基材料在现代社会中的广泛使用。研究了在碳纤维/水泥界面处形成的热解碳薄层对CFRC输运和热电性能的增强作用。研究表明，它可以大大提高CFRC的电导率和塞贝克系数，从而获得更高的功率因数2.08 µW m− 1 K − 2和更高的热电优值3.11×10−3，与文献报道的和氧化物热电材料相当。具有热解碳层的CFRC均表现出典型的半导体行为，其导电激活能为0.228- 0.407eV，具有较高的Seebeck系数。通过Mott公式的计算表明，CFRC的电荷载流子密度（1014- 1016 cm −3）远小于典型热电材料的电荷载流子密度，并且随着碳层厚度的增加而增加。CFRC的热导率主要由声子热导率决定，水泥基体中高密度的微/纳米缺陷散射声子，缩短声子的平均自由程，从而使CFRC的热导率保持在较低水平，热解碳的无定形结构所诱导的适当载流子密度和迁移率是CFRC高热电优值的主要原因。
Thermoelectric properties of carbon fiber reinforced cement composites (CFRCs) have attracted relevant interest in recent years, due to their fascinating ability for harvesting ambient energy in urban areas and roads, and to the widespread use of cement-based materials in modern society. The enhanced effect of the thin pyrolytic carbon layer (formed at the carbon fiber/cement interface) on transport and thermoelectric properties of CFRCs has been studied. It has been demonstrated that it can enhance the electrical conduction and Seebeck coefficient of CFRCs greatly, resulting in higher power factor 2.08 µW m−1K−2and higher thermoelectric figure of merit 3.11×10−3, compared to those reported in the literature and comparable to oxide thermoelectric materials. All CFRCs with pyrolytic carbon layer, exhibit typical semiconductor behavior with activation energy of electrical conduction of 0.228-0.407 eV together with a high Seebeck coefficient. The calculation through Mott’s formula indicates the charge carrier density of CFRCs (1014–1016cm−3) to be much smaller than that of typical thermoelectric materials and to increase with the carbon layer thickness. CFRCs thermal conductivity is dominated by phonon thermal conductivity, which is kept at a low level by high density of micro/nano-sized defects in the cement matrix that scatter phonons and shorten their mean free path. The appropriate carrier density and mobility induced by the amorphous structure of pyrolytic carbon is primarily responsible for the high thermoelectric figure of merit.