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

Abstract

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