A high-thermal-conductivity, high-durability phase-change composite using a carbon fibre sheet as a supporting matrix

The practical application of low-temperature latent heat storage systems is limited by the low thermal conductivity of the phase-change material (PCM). We fabricated a phase-change composite (PCC) with high thermal conductivity (k) and a high thermal-conductivity-retention rate (k/k0) during thermal cycles to solve this problem. A new type of high-thermal-conductivity carbon fibre sheet (CFS) material was used to enhance the thermal conductivity of erythritol PCM. CFSs were stacked and compressed to form a 3D network structure of high thermal conductivity carbon fibre, then the porous structure was impregnated with liquid erythritol PCM in a vacuum. The thermal conductivity of the PCC was measured by using the laser flash method, and the microstructures were analysed by energy dispersive spectroscopy using a scanning electron microscope. Durability tests of 5 and 100 cycles, using differently shaped PCC samples, were conducted to investigate the thermal conductivity of the PCC. With the addition of 14.8 vol% CFS, the thermal conductivity of the PCC was improved to 24.4 W.m(-1).K-1 (32.4 times higher than that of a pure PCM), and the thermal conductivity retention rate after 100 thermal cycles reached 89.4%. High-thermal-conductivity carbon fibre network structures with high connectivity were established in the PCC before the durability test and after 100 thermal cycles. The fabricated PCC exhibited a high thermal conductivity with less enhancement material and prolonged durability.