Direct synthesis of porous aluminum nitride foams for enhancing heat transfer and anti-leakage performance of phase change materials

Organic phase change materials (PCMs) suffer from low thermal conductivity and easy leakage, which limit their application in heat storage and thermal management. In this work, porous AlN skeletons were synthesized to solve these problems of paraffin PCM. Using Al powders as raw material, porous AlN skeletons were prepared through the ice-templated method and the direct nitridation reaction. The skeletons were impregnated with paraffin to prepare phase change composites (PCCs). The thermal conductivity of the PCC with 55.6 wt% AlN reaches 9.1 W m⁻¹ K⁻¹ in the axial direction, which is 4550 % of paraffin. This PCC retains a high enthalpy of 105 J g⁻¹ and has good thermal stability. Moreover, the porous AlN skeletons can effectively absorb paraffin so that all PCCs maintain a stable shape. This study provides a simple and efficient method to synthesize porous AlN and to solve the heat conduction and leakage issues of PCMs.