电驱动PEG/EG复合相变材料的制备与性能

以聚乙二醇（PEG）为相变组分，膨胀石墨（EG）为支撑材料，采用真空浸渍的方法制备了PEG/EG电热转换相变储能材料。改变复合相变材料中EG的质量分数，探究其在电热转换与热能存储效率、定形效果、相变焓值、储放热速率等方面的作用。结果表明，EG不仅能够提高复合相变材料的导热性能，还赋予其导电性能。当EG质量分数为5%时，PEG/EG复合相变材料具有良好的电热转换性能，在外加电压为7 V时，其电热转换与热能存储效率达到80.6%。同时，复合相变材料表现出良好的定形效果、较高的相变焓值（152.2 J/g）和优异的导热性能，与纯PEG相比，其储热所用时间减少了73%，储放热速率大幅提高。因此，PEG/EG复合相变材料在电驱动热能存储系统和能量转换与存储等领域具有广阔的应用前景。

Preparation and properties of electrically driven PEG/EG composite shaped phase change materials

The PEG/EG electro-thermal energy conversion phase change materials (PCMs) are prepared by encapsulating polyethylene glycol (PEG) into expanded graphite (EG) support materials via the vacuum impregnation method. The electro-thermal conversion and thermal properties of the composites with various EG mass fraction are further investigated. The results show that EG not only improve the thermal conductivity of the materials, but also endow it with electric conductivity. When the mass fraction of EG is 5%, the electro-thermal conversion efficiency of PEG/EG composites PCMs reach 80.6% under a voltage of 7 V. In addition, the composites exhibit good shape-stability, high phase change enthalpy value (152.2 J/g) and excellent thermal conductivity. The time of PEG/EG in storing heat process is shortened by 73% compared with pure PEG. Therefore, the composites will have a broad application prospect in electro-thermal energy conversion system and thermal energy storage fields.