Enhanced thermal performance of form-stable composite phase-change materials supported by novel porous carbon spheres for thermal energy storage

Abstract

Abstract n-Octadecane/novel porous carbon composite phase-change materials (PCMs) containing a novel porous carbon as the supporting material for n-octadecane were successfully fabricated by vacuum impregnation. The novel porous carbon was first prepared using functionalized polystyrene nanoparticles as a template and soluble starch as a carbon source. The porous carbon spheres can adsorb n-octadecane, preventing them from leaking during the phase-change procedure, and providing them with high thermal conductivity as well as good mechanical and thermal stability. Results show that the novel porous carbon possesses a multi-porous and regular spherical structure with a specific surface area of 1100 cm2/g. Fourier-transform infrared spectroscopy and scanning-electron-microscopy images prove that n-octadecane/novel porous carbon composite PCMs were successfully prepared and exhibited a regular spherical profile. Differential scanning calorimetry reveals that the composite PCMs have an excellent energy storage property, and the latent heat can reach 170.5 J/g, which is higher than the theoretical value. Furthermore, the composite PCMs exhibited an outstanding thermal stability after 100 repeated thermal cycles, and the thermal conductivity were improved up to 0.631 W/(m∙K), which enhanced by 266% compared with n-octadecane. The composite PCMs also displayed a good shape stability without any leakage during heating at 40 °C. These results confirm that the composite PCMs are promising for thermal energy-storage application systems.