Latent heat storage using a metallic phase change material (PCM) is an attractive option for high-temperature thermal energy storage. However, there are serious technical barriers to applying a metallic PCM to practical applications, mainly caused by its high corrosivity. This study reports the fabrication of a pellet-type PCM composite, mainly composed of a microencapsulated metallic PCM, as a potentially viable solution to this issue. This microencapsulated PCM (MEPCM) has a core composed of Al-25 mass% Si, which acts as a PCM. Its shell is composed of Al₂O₃ (or a precursor of Al₂O₃), and grass frit was used as a sinter agent. The composites were fabricated by mixing the MEPCM with a sintering agent, pelletizing, and sintering. The PCM composites exhibited a melting point of ~577 °C and a latent heat of 108–122 J g⁻¹. The thermal conductivities of the PCM composites were in the range of 2.16–3.20 W m⁻¹ K⁻¹. The cycling performance demonstrated the good durability of the composites. There were no significant changes in the shape and chemical composition of the pellets, even after 300 cycles of melting and freezing tests. These results indicate that the concept of pellet-type composites using MEPCM developed in this study will overcome the technical barriers to utilizing metallic PCMs. Thermal energy storage structures in various shapes could be fabricated via the method for fabricating PCM composites proposed in this study. This concept therefore shows substantial promise for application in high-temperature thermal energy storage systems.

使用金属相变材料（PCM）的潜热存储是高温热能存储的一种有吸引力的选择。但是，将金属PCM应用于实际应用存在严重的技术障碍，这主要是由于其高腐蚀性引起的。这项研究报告了主要由微囊化金属PCM组成的颗粒型PCM复合材料的制造，作为对此问题的潜在可行解决方案。该微囊化PCM（MEPCM）具有由Al-25质量％Si构成的芯，该Al用作PCM。其壳由Al的₂ ö ₃（或Al的前体₂ ö ₃），然后将草料用作烧结剂。通过将MEPCM与烧结剂混合，造粒和烧结来制造复合材料。PCM复合材料的熔点为〜577°C，潜热为108-122 J g ^-1。PCM复合材料的热导率在2.16–3.20 W m ^-1 K ^-1的范围内。循环性能证明了复合材料的良好耐久性。即使经过300次融化和冷冻测试，颗粒的形状和化学组成也没有明显变化。这些结果表明，在这项研究中开发的使用MEPCM的粒状复合材料的概念将克服利用金属PCM的技术障碍。可以通过本研究提出的制造PCM复合材料的方法来制造各种形状的热能存储结构。因此，该概念显示出在高温热能存储系统中的应用前景。