Cellulose nanofibrous/MXene aerogel encapsulated phase change composites with excellent thermal energy conversion and storage capacity

Phase change materials (PCMs) have emerged as the most efficient thermal energy storage solutions due to their unique energy storage properties, but they inevitably have shortcomings such as easy leakage and single thermal energy conversion method. In order to solve these problems and expand the application scope of PCMs in the field of thermal energy storage, using cellulose nanofibers, MXene, PEG, and Fe3O4 as raw materials, combined with simple freeze-drying and vacuum impregnation techniques, a series of phase change composites (PCCs) with excellent solar/magnetothermal conversion properties were prepared. The solar-to-thermal conversion efficiencies of PCCs exceed 97.16%, and the lowest enthalpy value can still reach 151 J/g. When the content of Fe3O4 is 15%, the PCC exhibits good magnetothermal conversion ability, which can perform magnetothermal fast charging, and the PCC can rise from 17 °C to 85 °C in 130 s. Moreover, the PCCs have excellent thermal stability, which can remain stable below 350 °C, and the enthalpies value of the PCCs hardly decrease after 1000 cycles, showing great practical application value.