“Back‐to‐Back” Radial Layered Skeleton Converging Heat Flow to Assist in Thermal Conduction of Aramid Nanofibers/Graphene Phase Change Composite Materials

Abstract Although optimizing the design of thermal conductive frameworks to promote the collection, transportation, and storage of thermal energy in composite phase change materials (CPCMs) is widely studied, the research on oriented layered thermal conductive frameworks is still in the exploratory stage. Taking inspiration from the bidirectional ice template strategy, a new research approach is proposed on the influence of “oriented micro‐unit” in thermal conductivity frameworks on the photothermal mass transfer of CPCMs. Three aramid nanofibers graphene nanosheets aerogels with different “oriented micro‐unit” structures are prepared by the high‐energy ball milling and bidirectional freezing. The enthalpy values of the composite materials are within the range of 146–152 J g −1 . Photothermal conversion experiments, hot plate mass transfer experiments, solar‐thermal‐electric energy conversion experiments and multi‐physics field simulation analysis jointly show that the CPCMs with a “back‐to‐back” radial layered structure behaves the most outstanding photothermal conversion ability and heat transfer performance, with an increase in thermal conductivity of 173.3%, a photothermal conversion efficiency of 91.9%, and the maximum solar‐thermal‐electric output voltage of 303.3 mV. The design of “oriented micro‐unit” opens up new ideas for CPCMs in the field where directional heat transfer is required.