Design of phase change materials with radially assembled 3D boron nitride network for enhanced thermal energy storage

Abstract

Phase Change Materials (PCMs) have attracted significant attention due to their high latent heat and isothermal phase transition properties. However, their large-scale application in daily life has been limited by challenges such as low thermal conductivity and insufficient shape stability during phase transitions. In this study, boron nitride (BN) and chitosan (CS) aerogels were employed as 3D skeleton materials using an ice-templating method, where the controlled growth of ice crystals in radial pattern enabled the ordered alignment of thermally conductive fillers. A paraffin-based composite material was successfully fabricated. Compared with pure paraffin, the incorporation of only 15.11 vol% BN resulted in a 1944.5 % increase in thermal conductivity (4.089 W/mK). Furthermore, this value was 59.54 % higher than that of composites with randomly dispersed BN at the same concentration. Consequently, the composite exhibited excellent thermal cycling stability, a latent heat storage capacity exceeding 175.8 J/g, and effective leakage prevention at high temperatures, while maintaining an ultrahigh electrical resistivity (2.3 × 10¹¹ Ω·cm) and low dielectric loss. This work presents an innovative approach for developing thermally conductive and shape-stable composite PCMs for energy storage applications.