Matsumoto Masamichi, Yamaguchi Ryohei, Shima Keisuke, Mukaida Masakazu, Tomita Motohiro, Watanabe Takanobu, Ishida Takao, Fujigaya Tsuyohiko
Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, Nishi-ku, Japan.
Faculty of Science and Engineering, Waseda University, Shinjuku-ku, Japan.
Sci Technol Adv Mater. 2021 Apr 13;22(1):272-279. doi: 10.1080/14686996.2021.1902243.
The large anisotropic thermal conduction of a carbon nanotube (CNT) sheet that originates from the in-plane orientation of one-dimensional CNTs is disadvantageous for thermoelectric conversion using the Seebeck effect since the temperature gradient is difficult to maintain in the current flow direction. To control the orientation of the CNTs, polymer particles are introduced as orientation aligners upon sheet formation by vacuum filtration. The thermal conductivities in the in-plane direction decrease as the number of polymer particles in the sheet increases, while that in the through-plane direction increases. Consequently, a greater temperature gradient is observed for the anisotropy-controlled CNT sheet as compared to that detected for the CNT sheet without anisotropy control when a part of the sheet is heated, which results in a higher power density for the planar-type thermoelectric device. These findings are quite useful for the development of flexible and wearable thermoelectric batteries using CNT sheets.
碳纳米管（CNT）片材的大各向异性热传导源于一维碳纳米管的面内取向，这对于利用塞贝克效应进行热电转换是不利的，因为在电流流动方向上难以维持温度梯度。为了控制碳纳米管的取向，在通过真空过滤形成片材时引入聚合物颗粒作为取向排列剂。随着片材中聚合物颗粒数量的增加，面内方向的热导率降低，而垂直于平面方向的热导率增加。因此，当片材的一部分被加热时，与未进行各向异性控制的CNT片材相比，在各向异性控制的CNT片材中观察到更大的温度梯度，这导致平面型热电装置具有更高的功率密度。这些发现对于使用CNT片材开发柔性可穿戴热电电池非常有用。
