Polyethylene Glycol–CaCl2 Coordination Compounds as a Novel Form‐Stable Phase Change Material with Excellent Thermophysical Properties

Abstract

Polyethylene glycols (PEGs) have been extensively studied as phase change materials (PCMs). To overcome the problem of liquid leakage, the authors firstly report a novel form‐stable phase change material (FSPCM) using coordination compound. The structure, morphology, thermal property, and thermal stability of the self‐prepared samples are determined. The obtained results confirm the existence of coordination bonds between PEG and Ca2+ species, and no liquid leakage is observed for the synthesized PEG–CaCl2 composites at temperatures as high as 120 °C. The PEG8000–CaCl2 (1:2) FSPCM exhibits a relatively large latent heat of 147.7 J g−1, corresponding to 87.8% of that of pure PEG. From the dynamical viewpoint, the activation energy of crystallization process is increased by only 5.2% for the PEG8000–CaCl2 composite due to the formation of coordination bonds; however, the activation energy is reduced by 18.3% during melting process. After adding 3 wt% conductive carbon black, the heat storage performance of the PEG phase change material can be optimized. The PEG‐CaCl2 composite would be a promising material for thermal energy storage applications and can be used in various engineering fields.