Modulation and optimisation of the properties of n-decanoic acid-tetradecanol phase change materials by nanocomposite carbon materials prepared by atomic layer deposition methods

Abstract

Phase change materials limit practical applications due to their relatively weak thermal conductivity and leakage resistance. The present work focuses on the development of a novel composite PCM (CA-TD/ZnO/EG), which was prepared by adsorbing a binary mixture of n-decanoic acid-tetradecanol (CA-TD) based on the combination of expanded graphite (EG) and zinc oxide (ZnO) nanoparticles. A new support material, ZnO/EG, was assembled by depositing specially shaped ZnO onto the surface of an expanded graphite substrate using an atomic deposition method. In addition to maintaining the porous structure of EG and preventing the leakage of CA-TD, the ZnO/EG reduces the interfacial thermal resistance between the substrate and the PCM molecules, which leads to the maximisation of the thermal conductivity. The prepared CA-TD/ZnO/EG-10 composite has a phase transition temperature of 19.5 °C, a heat of 157.3 J/g, and a thermal conductivity of (6.131 W·m−1·K−1) improved by 351.7% compared to the CA-TD material. Its faster heat transfer rate is directly reflected in the infrared image, with a small enthalpy change of 1.2% during 200 cycles of heating-cooling, as well as some photothermal conversion capability. The results of this paper can provide prospects for the functional design, modification, and enhancement of composite PCM.