Large-scale preparation of flexible phase change composites with synergistically enhanced thermally conductive network for efficient low-grade thermal energy recovery and utilization

In this study, the ethylene-propylene-diene monomer (EPDM) encapsulated paraffin wax (PW)-based shape-stabilized phase change composites (SSPCCs) with excellent thermal conductivity were prepared via the simple melt blending under the assistance of green steam explosion. The thermal conductivity of SSPCC (S6) with 12.5 wt% expanded graphite and 2.5 wt% carbon nanotube is 858 % (2.11 W/mK) of the thermal conductivity of EPDM/PW (S1) and achieved a 313 % enhancement compared with the control sample without steam explosion (S5). The improved thermal conductivity enables the obtained SSPCC to exhibit enhanced thermal energy storage and release rate which benefits to the thermoelectric conversion to drive the electric car race, providing a new avenue for recovered low-grade thermal energy utilization. In addition, the obtained SSPCCs displayed excellent shape stability and flexibility, coupled with high heat storage density and excellent reusability, exhibiting broad prospects in low-grade thermal energy recovery and high-efficiency energy utilization.