Flexible graphene aerogel-based phase change film for solar-thermal energy conversion and storage in personal thermal management applications

Developing phase change materials (PCMs) with solar-thermal energy conversion and storage for wearable personal thermal management is of significance but challenging, due to the difficulty of overcoming the liquid phase leakage, weak light adsorption, and solid phase rigidity of conventional phase change materials. In this work, a novel flexible graphene aerogel based composite phase change film (CPCF) has been successfully designed and constructed. In this CPCF, the introduction of polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) can strengthen the porous framework of graphene aerogel (GA) and endow the graphene aerogel film (GAF) with superior flexibility. The final CPCF has been obtained by impregnating paraffin wax (PW) into the GAF supporting matrix. This GAF-PW CPCF behaves excellent thermal property, long-term cycle stability, advanced flexibility, and outstanding solar-thermal conversion ability. The phase change enthalpy of the GAF-PW CPCF can reach 154.64 J/g and stay almost unchanged even after 500 heating-cooling cycles. Most importantly, the solar-thermal conversion efficiency of the GAF-PW CPCF is evaluated to be 95.98%, indicating its superior ability to convert solar energy into thermal energy. The flexible GAF-PW CPCF can be easily attached on a human model to demonstrate its advanced performance of wearable thermal management. This flexible CPCF developed in this work exhibits great potential to be applicable in the fields of wearable personal thermal management, providing a promising direction for the development of wearable fabric to enhance the adaptability of human body in cold environment.