High thermal-conductive phase change material by carbon fiber orientation for thermal management and energy conversion application

The conventional method to enhance the thermal conductivity of phase change materials (PCMs) is greatly increasing the proportion of thermal conductive fillers, which undoubtedly leads to a large sacrifice of the latent heat. To overcome this limitation, we propose a novel strategy herein to secondarily enhance the thermal conductivity by orientating the thermal conductive fillers of carbon fibers (CFs). The orientated CFs distribute uniformly and form a continuous thermal conductive skeleton in the obtained composite PCM (CPCM). Thus, the thermal conductivity of the CPCM with orientated CFs greatly increases to 6.31 W/(m<middle dot>K) along the axial direction of the CFs, more than twice as high as that of the conventional CPCM without CF orientation. In addition, the CPCM possesses a large latent heat of 131 J/g, a suitable phase change temperature region of 45 similar to 65 degrees C and a great leakage-proof property. As a result, the obtained CPCM demonstrates great heat-transfer and heat-absorbing abilities. For example, in thermal management application, the maximum temperature of the simulative electronic device can be controlled below 40.8 degrees C with a heating rate of 3 W, 5.8 degrees C lower than that with conventional CPCM. For the photothermal conversion application, the CF-orientated CPCM shows a much higher conversion efficiency than the conventional CPCM (83.5 % vs. 75.5 %).