Preparation and characterization of erythritol/sepiolite/exfoliated graphite nanoplatelets form-stable phase change material with high thermal conductivity and suppressed supercooling

Sepiolite (Sep) and exfoliated graphite nanoplatelets (xGnP) were applied as supporting material and thermal conductive fillers to solve the problems of possible leakage, low thermal conductivity and high supercooling of m-erythritol (ME) as a phase change material (PCM). The loading of ME in the ME/Sep form-stable PCMs could attain 56 wt% when the Sep was treated by 2.5 M HC1 and heated at 800 degrees C for 1 h. The form-stable PCMs were basically physical mixtures though there were some interactions occurred between the hydroxyl groups of ME and Sep. The thermal stability of ME was improved after it was confined in the supporting materials. In addition, the thermal conductivity of the ME/Sep/xGnP form-stable PCM containing 56% ME and 8.0 wt% xGnP could be enhanced to 0.756 W/mK, which was 103% higher than the corresponding ME/Sep form-stable PCM. Moreover, the transient temperature response of the form-stable PCMs was greatly improved by Sep and xGnP. Furthermore, the supercooling of ME could be decreased from 80 degrees C for pure ME to about 30 degrees C in the ME/Sep/xGnP form-stable PCM containing 56% ME and 8.0 wt% xGnP. Besides, the latent heat recovery ratio of the ME/Sep/xGnP form-stable PCMs were also greatly improved.