Multifunctional Graphene Composites for Electromagnetic Shielding and Thermal Management at Elevated Temperatures

A method for scalable synthesis of epoxy composites with graphene and few-layer graphene fillers is described, and the electromagnetic interference (EMI) shielding and thermal properties of such composites at elevated temperatures are reported. The tested materials reveal excellent total EMI shielding of SET approximate to 65 dB (approximate to 105 dB) at a thickness of 1 mm (approximate to 2 mm) in the X-band frequency range. At higher filler loading fractions, composites reveal a room-temperature cross-plane thermal conductivity of 11.2 +/- 0.9 Wm(-1) K-1, which is a factor of x41 larger than that of the pristine epoxy. Interestingly, the EMI shielding efficiency improves further as the temperature increases while the thermal conductivity remains approximately constant. The enhancement in the EMI shielding is explained by the temperature dependence of the two electrical conduction mechanisms, electronic band-type conduction inside the fillers, and hopping conduction between the fillers. The excellent EMI shielding and heat conduction characteristics of such multifunctional graphene composites at high temperatures are promising for packaging applications of microwave components where EMI shielding and thermal management are important design considerations.