Abstract
The changes in the conductivity type, capacitance value, and equivalent circuit models of the composite materials, taking into account the impact of graphene-bentonite covers on the aluminum carrier, are discussed. The EIS spectra of the pure aluminum foil lay in the positive reactive resistance domain characterized by the impact of the inductance. The conductivity value is 3.9± 0.1 Sm/cm with decreasing electrostatic capacitance from 0.08 to 0.02 F/g in the frequency range 10-1÷104 Hz. Applying the graphene-bentonite coating changes types of conductivity, from electron type to ionic type. Conductivity has two orders smaller value, and rises with increasing the frequency from 0.014 to 0.02 Sm/cm. The electrochemical equivalent circuit in the case of covering by graphene-bentonite mixtures is the R-CPE parallel circuit has characteristic of the porous electrodes in a supercapacitor. Presence of a dielectric component (bentonite) on the foil surface limits the polarization of composite material and decreases the capacitance value.
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