Double percolation approach for hybrid graphene Nanoplatelet-Carbon black nanocomposites based on electrical impedance Spectroscopy

A double -percolation model for predicting electrical properties in hybrid carbon black (CB)-graphene nanoplatelet (GNP) nanocomposites is proposed. This model is based on DC and EIS measurements. From DC measurements, a non -ohmic behavior is observed for low -filled nanocomposites whereas at high -filled ones, an ohmic behavior is noticed. From EIS analysis, the behavior of the system can be modeled by an equivalent circuit formed by a series of inductance -resistance capacitance (LRC), for contact and intrinsic electrical mechanisms, and resistance -capacitance (RC) elements, for tunneling transport, where the capacitances are substituted by Constant Phase Elements (CPEs) due to the presence of scattering effects. The complex impedance analysis shows a GNP -dominated electrical behavior at a high CB/GNP ratio. At a medium CB/GNP ratio a double percolating network is formed. At a low CB/GNP ratio, the electrical transport is CB -dominated. The proposed model based on the classical percolation theory with a double threshold properly fits the electrical measurements.