Natural flake graphite was chemically intercalated to prepare expandable graphite. The expandable graphite was then expanded by means of microwave irradiation to obtain expanded graphite (EG). Tetradecanol (TD)/EG composite form-stable phase change materials (PCMs) were prepared by mixing TD with EG through an autoclave method. The highest loading of TD in the composite form-stable PCMs with good form-stability was 93 wt%. The composite form-stable PCMs exhibited excellent thermal energy storage capacity. The melting enthalpy (Delta H-m) and crystallization enthalpy (Delta H-c) of the composite form-stable PCM containing 93 wt% TD were 202.6 and 201.2 J/g, respectively. However, the solid-solid phase transition of TD in the composite form-stable PCMs was hindered as TD was strongly absorbed by EG. As a result, the Delta H-m and Delta H-c of the composite form-stable PCMs were slightly lower than the theoretical value. The thermal conductivity of the composite form-stable PCMs was greatly enhanced by EG and was increased with the increasing of EG loading. The thermal conductivity of the composite form-stable PCM containing 7 wt% EG attained 2.76 W/m K. Besides, effects of the prepared EG on properties of the composite form-stable PCMs were compared with those of EG derived from commercially obtained expandable graphite. (C) 2014 Elsevier B.V. All rights reserved.