Polyethylene glycol (PEG) is one of organic phase change materials with low thermal conductivity, which hindered the application of the PCM. In this paper, PEG/expanded graphite (EG) with the different mass fraction was prepared and the thermal properties were investigated first. And then, experiments of latent heat thermal energy storage (LHTES) with pure PEG and PEG/EG PCMs were conducted to investigate the temperature involutions at certain position in LHTES during the charging and discharging processes. Compared with the pure PEG, LHTES with PEG/EG can dramatically enhance the heat transfer rate with little latent heat loss. (C) 2015 Elsevier B.V. All rights reserved.