As phase change thermal storage material, sodium acetate trihydrate (CH3COONa center dot 3H(2)O) exhibits large thermal capacity and holds tremendous promise. However, main problems of undercooling of solidification and phase stratification constrained its application in energy storage. Thus, present work prepared a new composite phase change thermal storage material of sodium acetate trihydrate mixed with nucleating agent and thickening agent. The initial research results showed that addition of an appropriate proportion of nucleating agent tetrasodium pyrophosphate decahydrate led to a good restrain to the undercooling of CH3COONa center dot 3H(2)O. A certain amount of thickening agent polyacrylamide could also avoid the phenomenon of phase stratification and maintain the heat storage capacity of samples. Meanwhile, the additions little affected the melting point and would not decrease the enthalpy of fusion of sodium acetate trihydrate as established from Differential Scanning Calorimetry study, which indicated that this novel composite material possessed excellent and stable performance suitable for its application for thermal energy storage systems. (C) 2018 Elsevier Ltd. All rights reserved.