High-thermal-conductivity phase-change composites prepared by in situ synthesis of graphite Nanoplatelets/Cu networks for effective thermal management

• A network of graphite nanoplatelets (GNPs) and Cu nanoparticles phase change composites (PCCs) with high thermal conductivity and leakage prevention. • Compared with pure paraffin wax, the thermal conductivity of EG/Cu/PW is 34.26 W m −1 k −1 , significantly increased by 170 times. • In the thermal management test, the resultant phase change composites block shows efficient and reliable thermal management performance. Phase-change materials show considerable potential for the thermal management and thermal energy harvesting of electronics and appliances. However, the utilization of phase change materials (PCMs) for high-performance thermal management is hampered by low thermal conductivity and leakage problems. Herein, we report a novel method for preparing phase change composites (PCCs) with high thermal conductivity and inhibited leakage by constructing a network of graphite nanoplatelets (GNPs) and Cu nanoparticles (100 - 500 nm) with paraffin (PW) as the functional matrix. The study results demonstrated that under loads of 22 wt% EG and 45 wt% Cu, the thermal conductivity of the PCC sample reached 34.26 W m −1 k −1 , which is a 258% increase over that of EG/PW (13.29 W m −1 k −1 ) and a 17000% increase over that of PW (0.2 W m −1 k −1 ). In addition, at ambient room temperature, the incorporation of PCCs can reduce the working temperature of a heating chip by more than 12-13 K, showing efficient and reliable thermal management performance. Skilfully designed PCCs can serve as an effective device for high energy density heat dissipation and thermal storage. The proposed method is a promising approach for preparing PCCs for use in large-scale heat storage and electronic equipment thermal management.