Novel PEG₆₀₀₀-Silica-MWCNTs Shape-Stabilized Composite Phase-Change Materials (ssCPCMs) for Thermal-Energy Storage

Area of Science:

• Materials Science
• Chemical Engineering
• Energy Storage

Background:

• Phase change materials (PCMs) are crucial for latent heat storage.
• Leakage and poor thermal conductivity limit the application of traditional PCMs.
• Developing shape-stabilized PCMs (ssPCMs) with enhanced thermal properties is essential.

Purpose of the Study:

• To prepare and characterize novel PEG6000-silica-MWCNTs composites as ssPCMs.
• To determine the optimal PEG6000 content to prevent leakage during thermal cycling.
• To evaluate the thermal performance and stability of the developed ssPCMs.

Main Methods:

• Covalent bonding of PEG6000 and MWCNTs-OH to an in-situ generated silica matrix via urethane bonds.
• Sol-gel process to create the organic-inorganic hybrid structure.
• Scanning Electron Microscopy (SEM), X-ray, and Raman spectroscopy for morphological and structural analysis.
• Thermal cycling tests to assess stability and leakage.

Main Results:

• An optimal PEG6000/NCOTEOS molar ratio of 2/1 (~91.5% PEG6000) was identified, preventing PEG leakage.
• The composite exhibited high phase-transition enthalpies (~153 J/g) and good storage efficiency (~84%).
• SEM, X-ray, and Raman analyses confirmed the composite's structure with silica distributed within the PEG matrix.
• The ssPCM demonstrated excellent chemical stability over 450 thermal cycles.

Conclusions:

• The developed PEG6000-silica-MWCNTs composite is an effective ssPCM for latent heat storage.
• The covalent linkage and silica matrix successfully immobilize PEG6000, ensuring shape stability.
• The material offers high energy storage capacity and long-term thermal stability, suitable for practical applications.