Exfoliated graphite nanoplatelets (xGnP) were applied to enhance the thermal conductivity of polyaniline (PANI) based form-stable phase change materials (PCMs). The xGnP was first dispersed in palmitic acid (PA) uniformly under the assistance of ultra-sonication. The xGnP/PA mixture was then applied to prepare PA/PANI/xGnP form-stable PCMs, in which PANI was obtained by means of surface polymerization of aniline and acted as supporting material. The content of PA in the prepared form-stable PCMs was fixed as 75 wt%. The structure, thermal energy storage properties and thermal conductivity of the PA/PANI/xGnP form-stable PCMs were investigated. The results showed that the thermal conductivity of the prepared form-stable PCMs could be greatly improved by xGnP while the thermal energy storage capacity was maintained. The thermal conductivity and thermal energy storage capacity of the PA/PANI/xGnP form-stable PCM doped with 7.87 wt% of xGnP could attain 1.08 W/(m K) and 157.7 J/g, respectively. The thermal conductivity was 237.5% higher than that of PA/PANI form-stable PCM. The prepared PA/PANI/xGnP form-stable PCM is expected to exhibit better performance in solar thermal energy applications. (C) 2013 Elsevier Ltd. All rights reserved.