Graphene platelets/aluminium nitride metacomposites with double percolation property of thermal and electrical conductivity

Graphene platelets/aluminium nitride (GPLs/AlN) metacomposites with double percolation property of thermal and electrical conductivity were successfully fabricated by spark plasma sintering. Microstructures and phase composition of the GPLs/AlN metacomposites were investigated by field emission scanning electron microscopy, X-ray diffraction and Raman spectroscopy. With increase of the GPLs contents, the double percolation property of thermal (19.27 wt% GPL) and electrical conductivity (19.03 wt% GPL) was found. Moreover, the negative permittivity behavior was also observed when the GPLs content reached 19.50 wt%, which was attributed to the formation of continuous GPLs networks. Finally, the equivalent circuit models were used to analyze the negative permittivity behavior. As the reactance (Z′′) converted from negative to positive, the inductors were introduced into the equivalent circuit models, and the GPLs/AlN metacomposites went through the capacitive-inductive transition with the increasing GPLs content, corresponding to the negative permittivity behavior.