Preparation and thermal characterization of sodium acetate trihydrate/expanded graphite composite phase change material

Abstract

The sodium acetate trihydrate (SAT)/expanded graphite (EG) composite phase change material (PCM) was firstly prepared by absorbing liquid SAT into a porous network of EG, in which SAT acted as the PCM. EG prepared at microwave irradiation power of 800 W for 30 s with maximum volumes has the largest sorption capacity for SAT. At the mass fraction of SAT <95 %, SAT uniformly disperse in the pores of EG without liquid leakage evidenced from scanning electron microscopy characterization. X-ray diffraction results further show that PCM is just a combination between SAT and EG without any chemical reaction. Differential scanning calorimeter measurements indicate that the melting temperature and latent heat of the composite PCM are 59.5 °C and 202 J g−1, respectively, close to those of pure SAT. The thermal conductivity of the composite PCM can be as high as 1.589 W m−1 K−1.The form-stable SAT/EG composite with SAT mass fraction of 95 % has great potential in thermal energy storage due to its moderate melting point, significant latent heat storage capacity, form-stable property, direct usability without need for an extra storage container, and high thermal conductivity.