In this study, high performance composite phase change materials (PCMs) were created. Graphene oxide (GO) nanosheets were used as supporting materials to keep the shape of polyethylene glycol (PEG) stable during phase change, and graphene nanoplatelets (GNP) were used as conductive fillers. Thermal conductivity was measured with a transient plane source method. Thermal conductivity was found to increase linearly with GNP loading, and PEG/GO/GNP composite PCMs exhibited higher ...