Polyethylene glycol/modified carbon foam composites for efficient light-thermal conversion and storage

Abstract

The limited light absorption, low thermal conductivity, and poor shape stability restrict the widespread application of organic phase change materials (PCMs). Herein, carbon foam (CF) with the light, inter-connective porous, and high-strength was developed based on the phenolic resin to encapsulate organic PCMs, and multi-walled carbon nanotubes (MWCNTs) were added to improve the compressive strength and light absorption at the same time. Then, the polyethylene glycol (PEG) was encapsulated in the CF/MWCNTs composite via a vacuum impregnation method. The modified CF composite could act as an efficient heat transfer channel to improve the thermal conductivity and light-thermal conversion efficiency of PEG. As a result, the PEG/CF composites displayed a high latent enthalpy (156.3 J/g to 170.9 J/g) and an excellent light-thermal conversion efficiency (61%–74%). Furthermore, the PEG/CF10 exhibited the highest thermal conductivity of 0.68 W/(m∙K), which is about 2.24 times higher than that of pure PEG. The as-prepared PEG/CF composites with mechanical strength and thermal stability could exhibit great potential in solar energy utilization, building energy conservation, and waste heat recovery.