Paraffin-chitin nanofibers bifunctional composite foam for thermal insulation and energy storage

Dimensionally stable paraffin-chitin nanofibers bifunctional composite foams with excellent thermal energy storage performance and promising thermal insulation properties were successfully constructed. Pickering emulsions of paraffin stabilized by chitin nanofibers were first prepared and then assembled with chitin nanofibers to form porous structures after freeze-drying. As a result, the maximum paraffin content in the product can reach 95.3%. Correspondingly, a maximum latent enthalpy value of 197.5 and 197.2 J/g for melting enthalpy and crystallization enthalpy (approximately 91.7 and 92.2% of that of pure paraffin), with the relative retention of 96.2 and 96.7% are achieved, demonstrating its excellent energy storage capacity. The foam can withstand 232 times its weight at a temperature of 180 °C without leakage, proving its excellent high-temperature dimensional stability. The composite foam also exhibits low thermal conductivity (65 mW/m^.K) for heat shielding applications. The sustainability, reproducibility, and excellent thermal regulation performances of composite foam give it great application prospects in the field of energy collection and storage.