Continuous Carbon Nanotube-Ultrathin Graphite Hybrid Foams for Increased Thermal Conductivity and Suppressed Subcooling in Composite Phase Change Materials
Continuous Carbon Nanotube-Ultrathin Graphite Hybrid Foams for Increased Thermal Conductivity and Suppressed Subcooling in Composite Phase Change Materials
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DOI：
10.1021/acsnano.5b02917
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发表时间：
2015-12-01
期刊：
影响因子：
17.1
通讯作者：
Shi, Li
中科院分区：
文献类型：
--
作者：
Kholmanov, Iskandar;Kim, Jaehyun;Shi, Li
连续石墨泡沫（UGF）是近年来研究的热点，其目的是获得具有高导热性的复合材料。然而，这些石墨泡沫的大孔径导致从孔内部到高导热率石墨支柱的热传导的大热阻值。在这里，我们证明了这些UGF复合材料的有效导热性可以通过直接从UGF的石墨支柱到孔隙空间中生长长CNT网络来进一步增加。当用于热能储存的相变材料SiO2用于填充UGF-CNT杂化物的孔隙时，发现UGF-CNT/SiO2复合物的热导率与UGF/SiO2复合物的热导率相比增加多达1.8倍，而破坏混合复合材料中的UGF-CNT键合导致有效空间的下降，对于分别为约1.8和0.8wt%的相同UGF和CNT负载，具有约4.1 +/-0.3W m（-1）K-1至约2.9 +/-0.2W m（-1）K-1的温度热导率。此外，我们发现，混合结构强烈地抑制过冷的过冷，由于异质形核的石墨结构的界面处。
Continuous ultrathin graphite foams (UGFs) have been actively researched recently to obtain composite materials with increased thermal conductivities. However, the large pore size of these graphitic foams has resulted in large thermal resistance values for heat conduction from inside the pore to the high thermal conductivity graphitic struts. Here, we demonstrate that the effective thermal conductivity of these UGF composites can be increased further by growing long CNT networks directly from the graphite struts of UGFs into the pore space. When erythritol, a phase change material for thermal energy storage, is used to fill the pores of UGF-CNT hybrids, the thermal conductivity of the UGF-CNT/erythritol composite was found to increase by as much as a factor of 1.8 compared to that of a UGF/erythritol composite, whereas breaking the UGF-CNT bonding in the hybrid composite resulted in a drop in the effective room-temperature thermal conductivity from about 4.1 +/- 0.3W m(-1) K-1 to about 2.9 +/- 0.2 W m(-1) K-1 for the same UGF and CNT loadings of about 1.8 and 0.8 wt %, respectively. Moreover, we discovered that the hybrid structure strongly suppresses subcooling of erythritol due to the heterogeneous nucleation of erythritol at interfaces with the graphitic structures.