Shape stability and thermal performance of composite shape-stabilized phase change materials (SSPCMs) composed of poly(styrene-co-maleic anhydride)-g-octadecanol (SMAC18) comb-like polymer and graphene oxide (GO) nanoplatelets are studied under various GO contents. Thanks to the adsorption and protection of GO layered structure, SMAC18/GO SSPCMs exhibit a good phase change characteristics and shape-stabilized performance. At a higher temperature, 160 degrees C, which is far above the melting temperature of SMAC18, a stable appearance is revealed, and the thermal stability of SMAC18/GO shows a linear enhancement with GO contents, demonstrating the good thermal barrier effect from GO nano fillers. Thermal energy storage efficiency and thermal reliability after 500 thermal cycles are well proved, and the thermal buffer time is similar to that of SMAC18, indicating that GO nanoplatelets have a slightly effect on the heat-storage and release behavior during the phase change process. The combined physical adsorption and hydrogen bonding between GO and SMA matrix contributes the enhanced shape-stability and thermal performance of SMAC18/GO SSPCMs, offering a future perspective for energy storage applications. (C) 2016 Elsevier B.V. All rights reserved.