Enhancing the Thermal Performance of a Stearate Phase Change Material with Graphene Nanoplatelets and MgO Nanoparticles

The effectiveness of dispersed nanomaterials to improve the thermal performance of phase change materials (PCMs) is well-proven in the literature. The proposal of new engineered nanoenhanced phase change materials (NePCMs) with customized characteristics may lead to more efficient thermal energy storage (TES) systems. This work is focused on the development of new NePCMs based on the dispersions of graphene nanoplatelets (GnPs) or MgO nanoparticles in a stearate PCM. The new proposed materials were synthesized using a two-step method, and acetic acid was selected as a surfactant to improve the stability of the dispersions. An extensive characterization of the constitutive materials and the developed dispersions using different spectroscopy techniques is reported. Also, the GnP nanopowder was explored by using the XPS technique with the aim to characterize the used carbon nanomaterial. The obtained spectra were investigated in terms of the chemical bonds related to the observed peaks. The thermophysical profile (density, thermal conductivity, isobaric heat capacity, and thermal diffusivity) was experimentally determined once the main components of the NePCMs were characterized and dispersions were designed and developed. This discussion focuses on the differentiated and distinguished effects of the dispersed GnPs and MgO on the properties of the NePCMs. A comprehensive analysis of the measurements to elucidate the mechanism that promoted higher improvements using GnPs instead of MgO was performed.