Shape-stable phase change materials based on carboxymethyl chitosan/boron nitride nanosheets high-strength aerogel

The application of phase change materials (PCMs) in energy storage and temperature control systems holds significant promise for enhancing energy efficiency and environmental sustainability. Herein, the development of a boron nitride nano-aerogel-supported PCM, reinforced by carboxymethyl chitosan (CMCS) and oxidized corn starch (DCS) cross-linking was reported. This approach involved the utilization of polydopamine-modified boron nitride nanosheets (PDA@BNNS) for the fabrication of a thermally conductive skeleton, while carboxymethyl chitosan (CMCS) and oxidized corn starch (DCS) were utilized as reinforcing material and cross-linking agent, respectively. The skeleton was prepared via a sol-gel method and freeze-drying technique, while polyethylene glycol (PEG) was subsequently encapsulated using a vacuum impregnation method. Notably, the prepared skeleton exhibits a compressive stress of 12.18 MPa at 80 % strain, much higher than other boron nitride nanosheets aerogels reported in literature. The cross-linked boron nitride skeleton enhances the thermal conductivity of the composites by 137.4 % compared to pure PEG. Furthermore, due to the highly porous structure of the skeleton, the PEG mass fraction reaches 96.0 wt%, resulting in a phase change enthalpy of 181.5 J/g. The results suggest that this composite material is a promising PCM candidate for thermal energy storage applications.