Flame-retardant and leakage-proof phase change composites based on MXene/polyimide aerogels toward solar thermal energy harvesting

To address the problems of easy leakage and high flammability of phase change materials, a series of innovative leakage-proof phase change composites (PCCs) with excellent solar thermal conversion capability and superior flame retardancy have been successfully developed. Herein, two-dimensional layered MXene nanosheets with excellent solar-thermal conversion effect were first synthesized by etching MAX phase with lithium fluoride and hydrochloric acid solutions. MXene/polyimide (PI) aerogel was then prepared by freeze-drying and thermal imidization after MXene dispersions mixed with poly (amic acid). The MXene/PI aerogels were subsequently impregnated into polyethylene glycol (PEG) by vacuum impregnation to obtain new shape-stable MXene/PI@PEG phase change composites (MPPCCs). Among them, MPPCC-4 exhibits a very high PEG loading capacity (98.1%) and high enthalpy (167.9 J/g), and a relative enthalpy efficiency of 99.8%. When compared to PEG, MPPCC-4 has outstanding flame retardant properties, including a 26.2% lower peak heat release rate and an 11.6% lower total heat release rate. In conclusion, MPPCCs show considerable potential for application in solar energy utilization systems.

Automated summary

In this study, innovative leakage-proof phase change composites (PCCs) with excellent solar thermal conversion capability and superior flame retardancy were successfully developed. The PCCs showed high PEG loading capacity and enthalpy, and exhibited outstanding flame retardant properties.