Recent Progress in PEG-Based Composite Phase Change Materials

This review discusses advances in polyethylene glycol-based composite phase change materials (PCMs) for thermal energy storage (TES) and thermal regulation. PCMs utilize latent heat storage, absorbing and releasing energy during phase transitions within specific temperature ranges. Polyethylene glycol (PEG) is a promising organic PCM due to its easily tunable phase change temperatures, high melting/freezing enthalpies, and nontoxicity, among other advantages. However, PEG suffers from low thermal conductivity and requires encapsulation to contain the flow of liquified PEG. To address these issues, PEG has been composited with thermally conductive fillers and porous materials. Moreover, PEG has been modified to have enhanced photothermal conversion efficiency, decreased supercooling, and flame resistance. This review discusses exemplary developments in PEG-based composite PCMs, focusing on blending with different polymers, doping with various carbon materials (porous carbons, graphene, and carbon nanotubes), embedding into silica-based skeletons, and synergizing with other promising hosts and additives like layered doubled hydroxides, MXenes, and metal-organic frameworks. This work highlights key studies focused on implementing PEG-based PCMs in building, pavement, electronic, textile, solar, and waste heat recovery applications. The consequences of different synthesis parameters and their effects on the composite PCM's thermal transition properties are emphasized among the other results.