▎ 摘　　要

The development of high-power electronics, such as Li-ion batteries for electric cars, demands effective thermal management, because the temperature rise beyond the normal operating range is detrimental to the electronic performance. Due to its high thermal conductivity, graphene would be one of the ideal candidates for thermal management. But in graphene/polymer composites, thermal energy takes far more time to transfer through polymer chains than through graphene due to the vibration of polymer chains and phonon scattering. In this work, vertically aligned graphene tubes/polydimethylsiloxane (PDMS) composites were prepared and their thermal properties were characterized. Graphene loadings were controlled from 1.09 wt% to 4.5 wt% in the composites. The ordered-orientation of graphene in polymer facilitates the heat transfer. The results show that the thermal conductivity reaches 1.7 W-1 K-1, which is 10.8 times higher than that of pure PDMS. Incorporation of structured graphene can reduce the thermal expansion. It is forecasted that the prepared composites have considerable prospects in encapsulation and heat dissipation of electronic devices.