Enhanced thermal conductivity and energy conversion properties by a novel expanded graphite and reduced graphene oxide interconnected three-dimensional porous structure for constructing multifunctional phase change composites
摘要
The development of multifunctional, environmentally friendly, and energy-efficient composite phase change materials (CPCMs) is crucial for improving energy recovery and utilization in various applications and environments. Herein, we utilized the salt template method, assisted by polyvinylidene fluoride (PVDF), to design a novel three-dimensional porous carbon network based on expanded graphite (EG) and loaded with reduced graphene oxide (rGO) as an enhancing bridge. The resulting interconnected and dense three-dimensional porous carrier was employed for the melt encapsulation of octadecane (OD). DSC analysis revealed that the prepared CPCMs possess an excellent heat storage density of 168.93 J g−1 and a thermal storage capacity of > 99.9%. Notably, the continuous three-dimensional carbon network of EG and rGO in the CPCMs, with strong full-spectrum absorption and rapid photon and phonon transmission, led to a synergistic enhancement. The thermal conductivity of OD@6EG/PVDF/rGO reached 6.3840 W m−1 K−1, surpassing that of most carbon-based CPCMs. The composite material exhibited a photo-thermal conversion efficiency of 96.3% and an electro-thermal conversion efficiency of 74.4%, enabling the stable operation of a self-assembled photo-thermal-electric energy conversion system. After 200 heating–cooling cycles, the CPCMs demonstrated significant thermal and shape stability. Moreover, OD@EG/PVDF/rGO possessed self-cleaning and microwave absorption properties, expanding its potential for multifunctional applications. This study lays the foundation for the application of carbon-based materials in thermal management and energy conversion technology.
Graphical Abstract