Carbon nanotube-Cu foam hybrid reinforcements in composite phase change materials with enhanced thermal conductivity

Abstract

Organic phase change materials (PCM) have been regarded as one of the most promising candidates for the application of energy storage and temperature control due to their advantages in latent heat. However, their intrinsically low thermal conductivity (λ) is the Achilles heel, and the most common solution is to utilize thermal conductive reinforcements to fabricate composite PCMs. The research focus remains how to promote the efficiency of thermal conductive reinforcements. Here, a CNT-Cu foam hybrid reinforcement was fabricated through a high temperature tube furnace process. Different from conventional carbon film coated metal foam, CNTs with the length comparable to the pore size were radially grown on the surface of Cu foam with Ni catalysts, which can not only reduce the low-λ regions inside the foam skeleton, but also connect every branches of the foam to improve the integrity of the whole reinforcement, and the thermal conductivity of the composite was promoted to 3.49 W·m−1·K−1 from 0.105 W·m−1·K−1 of paraffin. Moreover, this reinforcement exhibited abilities to compensate the loss of latent heat and suppress the supercooling of the composite, indicating their great prospects in the application of phase change energy storage and temperature control. Keywords: Carbon nanotube, Cu foam, Phase change materials, Thermal conductivity