Shape stabilized Al-Si/Al2O3 phase change composites for high temperature heat storage

Latent heat storage employing metals as solid-liquid phase change materials (PCMs) has been a research hotspot in the area of high temperature energy storage. However, the major obstacles owing to the leakage and corrosion issues in the process of high-temperature phase change, the application of metallic PCM has been considerably restricted. In this study, Al-25Si alloy was used as PCM while Al2O3 nanoparticles were used as matrix material to prepare the phase change composite (PCC). Firstly, the mixed raw materials were pretreated in boiling water, which was subsequently shaped to tablets by pressing and finally heat treated at high temperature under O2 atmosphere. At a weight ratio of 50 wt% for Al-25Si in the mixture, the as-prepared PCCs were perfectly encapsulated and showed good thermal cycling stability, which could prevent leakage during the long time repeated heating and cooling. The PCC presented a melting temperature of around 577 °C and a heat storage enthalpy of around 85.4 J/g. The as-prepared composite with good thermal performance could find a wide application in high-temperature heat storage.