New shape-stabilized phase change materials (PCMs) composed of polyethylene glycol (PEG) and graphitic carbon nitride materials (bulk-C3N4 and CNIC) were prepared by a blending and impregnating method. The structural and thermal properties of the composites were investigated using various characterization techniques. The highest PEG content stabilized in the composite PCMs is 40 wt% for bulk-C3N4 and 60 wt% for CNIC. The crystallinity and phase change property of PEG/bulk-C3N4 PCMs are entirely damaged by the bulk-C3N4 stabilizer. For the PEG/CNIC PCMs with various PEG content, the phase change temperatures and the extent of supercooling show little difference and are much lower than those of pure PEG. The phase change temperatures, T-m and T-c, respectively decrease by similar to 24 degrees C and similar to 19 degrees C compared with pure PEG. The phase change enthalpies increase with higher PEG content. 60 wt% PEG/CNIC PCM has a relatively larger phase change enthalpy of 45.8 Jg(-1). This study suggests that the graphitic carbon nitride supporting materials are in favor of remarkably lowering the phase change temperature and the extent of supercooling of PCMs and will provide insights into the design of composite PCMs through employing new shape stabilization matrices. (C) 2015 Elsevier B.V. All rights reserved.