In this study, series of KCl-LiCl /expanded graphite (EG) composite phase change materials (CPCM) with different EG contents for high temperature thermal energy utilization were prepared by melting impregnation method. The mixture of KCl-LiCl was served as the phase change material (PCM) for thermal energy storage, while EG was acted as not only the matrix to prevent the leakage of PCM but also the heat transfer promoter to improve the thermal conductivity of PCM. The microstructures, phase transition properties, thermal conductivity and thermal stability of different samples were evaluated, and the results showed that KCl-LiCl was wrapped in the network structure of EG without agglomeration. The experimental latent heat of CPCMs were close to the theoretical value and there was no remarkable variation in melting point. The highest thermal conductivity of CPCMs was 12.05 W/(m•K), which is 41.6 times higher than that of KCl-LiCl. Moreover, the CPCMs whose EG content higher than 20 wt% showed good thermal stability after 100 thermal shock cycles. Furthermore, when 10 wt% SiC particles were added into 80KCl-LiCl/20EG, the compressive strength of 80KCl-LiCl/20EG/10SiC was enhanced to 9 MPa, which is 1.8 times higher than that of 80KCl-LiCl/20EG.

本研究采用熔融浸渍法制备了一系列不同EG含量的KCl-LiCl /膨胀石墨（EG）复合相变材料（CPCM），用于高温热能的利用。KCl-LiCl的混合物用作热能存储的相变材料（PCM），而EG不仅用作防止PCM泄漏的基质，而且还用作传热促进剂以提高PCM的导热性。评价了不同样品的微观结构，相变性能，导热系数和热稳定性，结果表明KCl-LiCl包裹在EG的网络结构中而没有团聚。CPCM的实验潜热接近理论值，熔点没有明显变化。CPCM的最高导热率是12.05 W /（m•K），是KCl-LiCl的41.6倍。此外，EG含量高于20wt％的CPCM在100次热冲击循环后显示出良好的热稳定性。此外，当将10wt％的SiC颗粒添加到80KCl-LiCl / 20EG中时，80KCl-LiCl / 20EG / 10SiC的抗压强度提高到9MPa，这是80KCl-LiCl / 20EG的1.8倍。