CNTs泡沫相变复合材料:纳米孔隙的构筑与相变材料的包裹

Composite of CNT foam and phase change material:nano pore structure and the packing of phase change material

热能是一种广泛存在并极具应用前景的能源,但目前储热材料的能量转换时间较长,储热效率较低,亟需一种高性能的新型储热材料。本工作通过化学气相沉积(chemical vapor deposition,CVD)方法利用碳纳米管(carbonnanotubes,CNTs)构筑宏观体材料,在微纳尺度下对复合材料结构进行优化,合成孔隙结构可控的 CNTs泡沫,利用毛细管作用力将熔融相变材料硬脂酸和石蜡填充到 CNTs 泡沫中,形成分散均匀的 CNTs相变复合材料。用聚焦离子/电子双束显微电镜(FIB/SEM)观察样品形貌,用差式扫描量热计(DSC)分析样品潜热,用 X 射线衍射仪(XRD)分析样品晶体结构,用拉伸试验机测试样品强度。结果表明:CNTs泡沫对相变材料具有优异的包裹性,减少了在相变循环中相变材料的流失;复合相变材料具有较高的潜热。

Thermal energy is a very promising and widely existing energy source. However, the current heat storage method of phase change material not only has a long energy conversion time but also has low heat storage efficiency. Carbon nanotubes (CNTs) based phase change composite materials were prepared by using the carbon nanotubes foam as the highly 3D thermal conductive network and impregnated with phase change material by capillary forces. The morphology of the sample was studied by FIB/SEM focused ion/electron double beam microscopy, showing excellent dispersion quality of CNTs throughout the matrix. The latent heat and crystal structure of the sample were analyzed by DSC and XRD respectively, based on which the mechanisms for the improvement of energy storage capability were investigated. Further, the mechanical properties of the sample were tested by tensile testing machine, and revealed high structural robustness which was very important for their practical applications. This study shows that the CNT foamed based on nanocomposite not only possess very high thermal energy storage efficiency, also reduces the phase change material loss in the circulation phase.