Malleable and Leakage-Proof Peg8000/Cacl₂/Sebs/Eg Composite Phase Change Materials for Advanced Battery Thermal Management

Abstract

Phase change materials (PCMs) have garnered significant attention for their potential in thermal energy storage and management. In this study, we synthesized a novel malleable and leakage-proof composite PCMs composed of polyethylene glycol (PEG8000), calcium chloride (CaCl₂), styrene-ethylene-butylene-styrene copolymer (SEBS), and expanded graphite (EG) through coordination reactions and physical blending. The morphology and thermal properties were characterized using transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) surface area analysis, X-ray diffraction (XRD), differential scanning calorimetry (DSC), and thermal conductivity testing. The results revealed that incorporating CaCl₂ into PEG8000 resulted in the formation of [H(OCH₂CH₂)₁₈₁OH]⋅2CaCl₂ coordination bonds, which effectively prevented liquid leakage. Benefiting from the established continuous thermally conductive pathways within the composites PEG8000/CaCl₂/SEBS/EG, the thermal conductivity of this composite is 5.95 times higher than that of PEG8000/CaCl₂. Additionally, this novel composite not only achieved enhanced thermal conductivity but also exhibited a high melting enthalpy of 167.5 J/g. Furthermore, when heated above its melting point (58.6 ℃), this composite remains malleable without leaking any liquid. It is easily shaped as desired and is suitable for large-scale production. With these excellent performances, this malleable and leakage-proof composite offers valuable insights for advanced battery thermal management.

Keywords: Malleable PCMs, leakage-proof, polyethylene glycol, enhanced thermal conductivity, advanced battery thermal management.