Preparation of coconut oil/aluminum nitride/expanded graphite composite phase change materials with high thermal conductivity and stable shape for thermal energy storage

Abstract

Phase change energy storage is one of the solutions to effectively deal with the problem of intermittency and spatial and temporal mismatch between supply and demand of new energy sources (solar, wind, etc.). However, phase change materials (PCMs) suffer from low thermal conductivity, which greatly affects energy storage and release efficiency. In this study, a novel shape-stable phase change material (SSPCM) was prepared by mixing coconut oil (CO) as a PCM with aluminum nitride (AlN) thermally conductive reinforcing particles and vacuum impregnated into expanded graphite (EG). The results showed that the thermal conductivity of the prepared SSPCM reached 2.985 W·m^–1·K^–1, which was 1765% higher than that of pure CO. The latent heat of SSPCM was 83.67 J·g^–1, which was 99% of the theoretical value. Furthermore, SSPCM showed excellent thermal stability and thermal cycle reliability. The proposed SSPCMs have the advantages of being renewable and simple preparation methods, which have great potential for application.