Temperature-dependent Dielectric Measurements of Polypyrrole/Zinc Cobalt Oxide Nanocomposites by Impedance Spectroscopy

This study characterizes the conduction mechanism in Zinc Cobalt oxide/Polypyrrole nanocomposites (ZCO/PPy NCs) concerning temperature (303–453 K) and frequency (100 Hz–1 MHz). To obtain the ZCO/PPy nanocomposites for the experiments, we used the in-situ chemical polymerization technique to disseminate varying weight percentages of ZCO nanoparticles (ZCO NPs) in the PPy matrix. The total electrical conductivity graph consists of a step-like feature of a plateau and dispersive regimes. The dispersive zone, which follows Jonscher's power law, correlates to AC conductivity, whereas the plateau region, which corresponds to DC conductivity, is thermally activated. The extracted DC conductivity values are of the order of 10^-4 S/m at 303 K. The conduction mechanism in ZCO/PPy nanocomposites is depicted by the Non-Overlapping Large Polaron Tunneling (NSPT) model. The dielectric studies confirm the non-Debye-like relaxation in PPy and ZCO/PPy NCs. In addition, the complex impedance and equivalent circuit analysis showed maximum contribution from grain and grain boundaries. The grain and grain boundary resistances are of the order of 10³ Ω, depicting the electrical homogeneity in the PPy and ZCO/PPy nanocomposites.