石墨烯泡沫热物性与界面热导温度相关性研究

Temperature dependent study on thermophysical properties of graphene foam and the correlation with interface thermal conductance

中文关键词: 石墨烯泡沫  热扩散率  热导率  界面热导  分子动力学

英文关键词: graphene foam, thermal conductivity, interface thermal conductance, molecular dynamics

中文摘要:

      石墨烯泡沫是将石墨烯立体化形成的复合材料，在锂离子电池等领域有较好的应用前景，而其导热性质成为限制工业应用的重要因素。基于瞬态电热技术，研究了石墨烯泡沫的导热性质及其随温度的变化。结果表明，不同于Umklapp声子散射机理，石墨烯泡沫的热导率随温度呈正相关性：由室温至373 K时，热导率由0.71 W/m·K升高至1.10 W/m·K。分析发现，泡沫内部的大量界面是其低导热性质的主要因素。利用分子动力学模拟验证了石墨烯与基体材料间的界面传热随温度成正相关，与宏观材料测量结果相符。

英文摘要:

      Graphene foam (GF) is a bulk composite material formed by graphene flakes and is promising in industrial applications such as Li-ion batteries. Although it is composed of graphene, the thermal property is significantly different from that of monolayer graphene due to the highly porous structure. The transient electro-thermal technique was employed to characterize the thermal properties of GF and its temperature dependence. It is found that thermal conductivity increases with temperature from 0.71 W/m·K to 1.1 W/m·K within temperature range from room temperature to 374K. The trend of thermal conductivity with respect to temperature is in contrast to the Umklapp phonon scattering theory. The existence of large amount of interfaces inside GF is the main reason responsible for such characteristic. In order to reveal the role of temperature on interface thermal transport, molecular dynamics simulation was employed to study the heat conduction property across graphene and matrix material. The effective thermal conductivity of local regime is increased, consistent with our measurement result for the temperature dependence of thermal property of GF.