IMPACT OF THE GRAPHENE SYNTHESIS AND CONCENTRATION CONDITIONS ON ELECTRICAL PARAMETERS OF GRAPHENE — GRAPHITE SYSTEM

Abstract

Electrochemical impedance spectroscopy was used to study the electrical parameters of graphite-graphene systems with different mass concentrations of graphene. Graphene was synthesized using two methods of plasma arc discharge from aqueous and non-aqueous medium (water and liquid nitrogen) to determine the impact of graphite concentration, water, and heat treatment of graphene on electrical parameters (conductivity and electrostatic capacity) of the graphite-graphene mixture. The average va­lues ​​of active resistance and electrostatic capacity of these systems are obtained. The optimal ratio of components with high capacitance and conductivity, which was 1: 1. The influence of heat treatment adsorbed on the graphene surface of the water and mass fraction of graphite on the change of electrical parameters of the system is shown. Comparison of the values ​​of capacity and active resistance of the samples showed that the presence of water in graphene reduces the average values ​​of capacity relative to graphene without water by 10 times and symbolically increases the active resistance at a mass ratio of graphene to graphite 1: 3, and at a ratio of 1: 1 values ​​are proportional. Comparison of resistance, capacitance, and charge distribution calculations in a graphite-graphene mixture in the frequency range 10–2 ÷ 103 Hz established the effect of heat treatment on increasing the values ​​of capacitance and active resistance. Heat treatment at 2500C of graphene, synthesized from an aqueous medium, leads to an increase in the values ​​of capacitance and conductivity, which occurs due to a different distribution of charges on the surface. Analysis of charge distribution maps shows that water adsorbed on the surface of graphene in the presence of a signi­ficant amount of graphite can be a factor in interfering with the distribution of charge carriers and significantly reduce the conductivity and electrostatic capacity of the system.