Hierarchical AlN/erythritol composite phase change materials with ultra-efficient polarity-enhanced heat conduction

It is essential to use hierarchically porous ceramics as conductive skeletons inside polymeric phase change materials (PCMs) to overcome the problem of low thermal conductivity. Actually, the interfacial thermal conductance plays a more important role in determining the phase change properties of the PCM. Here, we report a strong effect of surface polarity in improving interfacial thermal conductance. Porous aluminum nitride (AlN) is found to be an excellent skeleton for erythritol, an organic PCM. Their composition strongly reduces the degree of supercooling of erythritol from 68 to 20 K, while the porous diamond just reduces it to 29 K, despite its higher thermal conductivity. It is the polarity-enhanced AlN/erythritol adhesion that reduces the interfacial thermal resistance to one order of magnitude smaller than the diamond/erythritol contact. The overall performance can be further improved by loading nano-carbons, owing to the intimate contact between erythritol and the sp 2 carbon lattice.