N-eicosane/multilayer graphene composite phase change materials for electro-thermal conversion and storage

Phase change materials (PCMs) have many promising potentials for thermal energy conversion, storage, and utilization. However, several technical bottlenecks must to be solved such as poor thermal conductivity and leakage of liquid during the phase transition process. In this work, the n-eicosane (C20) was incorporated into the multilayer graphene (MLG), and the C20/MLG composite PCMs were fabricated through vacuum impregnation. The chemical stability, microstructure, and thermal behaviors of composites were characterized in detail. The DSC analysis shown that the C20/MLG composites have a latent heat value of 136.6-212.5 J g(-1) for melting with excellent crystallinity over 98%. The influence of MLG on thermal behavior was investigated and discussed. By adding 45 wt% MLG, the thermal conductivity of C20/MLG(45) (1.112 W m(-1) K-1) was 4.85 times that of C20 (0.289 W m(-1) K-1), and the thermal storage and release plots indicated the MLG considerably promoted the heat transfer performance of composites. The outstanding transient temperature response of C20/MLG(45) was recorded by the thermal infrared imager. Moreover, the C20/MLG(45) can effectively convert electricity to latent heat. The results of electro-thermal conversion measurement shown the electro-latent heat storage efficiency of C20/MLG(45) can exceed 59.9% at 1.9 V. In conclusion, the composite C20/MLG(45) have potentials in thermal energy storage applications including electro-thermal conversion and storage, building energy conservation and electrical power peak shifting.