A Novel Structure for Heat Transfer Enhancement in Phase Change Composite: Rolled Graphene Film Embedded in Graphene Foam

Phase change material (PCM) is an excellent heat storage material which can absorb a large amount of heat in the form of latent heat and can be used to improve the power generation effect of thermoelectric generator (TEG) in a fluctuating thermal environment. The thermal conductivity of PCM plays a key role. In this paper, graphene films as thermal conductive fillers were introduced into graphene foams through the ice-templated method. The composite structure can increase the thermal conductivity of paraffin by 44 times to 11.594 W/mK, and the corresponding mass fraction is only 1.14 wt %. On the other hand, the influence of thermal conductivity of PCM on TEG under periodic heat flux condition was analyzed through simulation. The results indicate that increasing thermal conductivity helps the PCM to better play a buffering effect, and significantly reduce the fluctuation of the power generation voltage.