Simple in situ synthesis of SiC nanofibers on graphite felt as a scaffold for improving performance of paraffin-based composite phase change materials

Abstract

A paraffin phase change material absorbed in a composite material of silicon carbide nanofibers and graphite fibers was prepared by vacuum impregnation to solve problems of current organic phase change materials, such as the low thermal response rate, low thermal conductivity, and high vulnerability to leakage. A composite material containing a phase change material as the scaffold combined with silicon carbide nanofibers is prepared by a simple vapor–solid reaction using industrially produced porous graphite felt as the raw material. The thermal conductivity of the composite phase change material is increased to 1.29 W m⁻¹ K⁻¹ by thermal strengthening of the supporting scaffold. Compared with the thermal conductivity of pure paraffin of 0.25 W m⁻¹ K⁻¹, not only is the thermal response rate improved, but the composite phase change material also exhibits chemical stability, shape stability, and stable thermal properties. The phase change enthalpies of the melting and freezing processes are 180.5 and 176.4 J g⁻¹, respectively. In addition, the use of low-cost graphite felt and the simple synthetic process of the composite phase change material facilitates large-scale production. Moreover, the composite is extremely flexible in terms of its shape design and has good energy storage properties in terms of photo-thermal conversion. These features promise to accelerate the effective application of the prepared composite phase change material in solar and buildings energy storage with great potential for application practices.