Enhancement on thermal properties of graphene/paraffin phase change microcapsules with connected thermal network

To address the challenges of paraffin leakage and low thermal conductivity during heat transfer processes, we developed microencapsulated phase change materials (MEPCMs) through an ultrasonic-electrostatic self-assembly strategy. The system features paraffin as the core and graphene nanosheets as a multifunctional shell, with hot-pressing consolidation effectively minimizing interfacial voids and contact resistance. The microstructure and thermal characterization revealed that the graphene shell simultaneously prevents paraffin leakage and establishes a continuous thermal conduction network. With graphene content of 10 wt%, the thermal conductivity of the MEPCMs increased from 0.22 W/(m·K) to 1.86 W/(m·K), accompanied by enhancements of 39.56% and 41.12% in heat storage and exothermic rates, respectively. Additionally, the enthalpy of phase transition of the MEPCMs reached 144.27 J/g. The MEPCMs prepared in this study demonstrated excellent thermal storage capacity and high thermal conductivity, highlighting their potential for applications in thermal energy storage and thermal management.