Reversible assembled gelatin aerogel-based phase change materials for light-to-thermal conversion and management

Employing 3D frameworks to construct composite phase change materials (PCMs) with excellent shape stability and solar-thermal conversion capacity has been proven to be a promising strategy. However, the recycle of effective components in composite PCMs is barely concerned. In this work, reversible assembled composite PCMs are designed by integrating gelatin/CNT (GC) aerogel with paraffin wax (PW), denoted as PGC-x, where x refers to the mass percentage of CNT in GC aerogel. The porous structure of aerogel endows PGC-x with outstanding shape stability until 100 °C and high loading efficiency of PW, enabling the thermal enthalpy of composite PCMs above 164 J/g. In addition, PGC-x demonstrates superior light-to-thermal conversion performance contributed by the wide light absorbance of CNT and phase change of PW, which is further proved by the satisfied conversion efficiency and five highly consistent conversion curves. Moreover, the recovery rate of PW and CNT from PGC-x exceeds 90 % and 80 %, respectively, through simple separation process, disclosing their great potential to reversible assembly, which greatly promotes the large-scale practical application of PCMs.