Graphene aerogel-phase change material host-guest smart films

Abstract Aerogel-phase change material (PCM) host-guest composites (A-PHCs), comprising of PCMs and aerogels, have attracted great attentions in various applications, such as thermal energy storage and smart textile, etc. However, A-PHCs usually suffer from intrinsic brittleness of solid PCMs and weak mechanical strength of aerogels, making the achievement of light, thin, flexible, and robust A-PHCs a great challenge. Herein, a densified graphene aerogel (d-GA) film with thickness of tens of micrometers, fabricated by press-forging of GA fibers, was utilized to make an aerogel-PCM host-guest film (APHF) by simple infiltration of PCM (e.g., paraffin) into the d-GA film. Benefitting from the compact porous structure of GA film, the as-obtained APHF exhibits superior mechanical strength and flexibility over pure PCM: the fracture strength was up to 29.6 MPa, about 3-20 times higher than those of any other reported APHFs and it can be bent into a camber with a bent angle (θ) of 180° and a small curve radius lower than ~300 μm. It also possesses high thermal conductivity (up to 2.0 W/mK), high energy density (~182.5 J/g), and thermosensitive imaging, thermal regulating, and thermal generating properties. These unique properties open a few applications for the APHFs to work as the advanced smart energy management units in the future portable and wearable systems.