In situ construction of vertically aligned AlN skeletons for enhancing the thermal conductivity of stearic acid-based phase-change composites

Abstract

As the global energy crisis intensifies, phase change materials (PCMs) for energy storage have attracted increasing attention in thermal energy storage and thermal management fields. However, due to the lack of an effective thermally conductive network inside, traditional PCMs generally exhibit low thermal conductivity, seriously hampering their practical applications. In this study, vertically aligned AlN skeletons were rationally constructed by freezing casting combined with an in situ carbothermal reduction method and further used as reinforcements to enhance the thermal conductivity of stearic acid (SA)-based PCMs. Benefiting from fast heat transfer channels constructed by the tightly oriented arrangement of AlN particles, the AlN/SA PCMs achieved a highest thermal conductivity of ∼5.74 W m⁻¹ K⁻¹ at a 47.9 vol% filling fraction, exhibiting a thermal conductivity enhancement of 2633.33% compared with that of pure SA. Furthermore, the as-prepared AlN/SA PCMs also exhibited competitive phase transition latent heat, superior thermal stability and liquid leakage resistance, presenting significant application prospects in the fields of thermal management and thermal storage.