Thermoconductive n-alkane enables ultra-high shape/thermal stability, durability, and ambient thermal energy harvesting

Thermal energy storage using phase change materials (PCMs) has received significant attention in the field of sustainable energy development. However, extremely low thermal conductivity and seepage issues are two long-standing drawbacks limiting PCM-based applications. In this study, an alternative strategy is used to construct composite PCMs by introducing hybrid functional materials as support and liquid n-alkane as energy storage material through a facile vacuum impregnation method. The hybrid functional material, obtained from a commercially available natural mineral, montmorillonite (Mt), and boron nitride, possesses high specific surface area and physicochemical stability and can endow the n-dodecane (DA) with beneficial characteristics. Hybrid-functional-material-supported DA is suitable for ambient energy harvesting in the form of latent heat, with a 309% growth rate in energy storage capacity compared with that of Mt/DA. The thermal conductivity reached 0.795 W/m·K, which is 2.01 and 5.89 times higher than those of Mt/DA and pristine DA, respectively. In addition, the composite PCMs exhibited ultra-high leakage resistance at up to 120 °C owing to the presence of a favorable interconnected network structure, strong surface tension, and capillary forces. The materials also exhibited high durability after 50 thermal cycles with a high latent heat retention capacity (>98%). Because of such thermal properties, the application scope of composite PCMs can be extended to the development of various human comfort thermal management systems.