Preparation and performances of sunlight-induced phase change PEG/SiO2-dye composite for solar energy conversion and storage

Abstract

Sunlight-induced phase-change PEG/SiO2-dye composites based on poly(ethylene glycol) (PEG) and dye-grafted silicon dioxide (SiO2) network were prepared by a facile sol-gel process. The structure and thermal properties of PEG/SiO2-dye composites were characterized by FT-IR, XRD, SEM, DSC and TG. The developed PEG/SiO2-dye composites exhibited unique characteristics, such as excellent shape-stabilized properties, thermal stability, a broad sunlight absorption range, and high phase change enthalpy (167.0 J/g). More importantly, the PEG/SiO2-dye composites exhibited a high light-to-thermal energy conversion and storage efficiency (85%–88%). After 300 light-induced phase transition cycles, PEG/SiO2-dye composites maintained thermal reliability and long-term sunlight exposure durability. Thus, PEG/SiO2-dye composites as a novel sunlight-induced phase change material showed great potential for applications in solar energy conversion and storage.