• Chabecki, P.
• Bordun, I.
• Malovanyy, M.
• Chwastek, K.

Abstract

<jats:title>Abstract</jats:title><jats:p>The influence of ultrasonic radiation in the cavitation regime on the structural and electrochemical properties of activated carbon was studied. It was established, as the result of the X‐ray diffraction and nitrogen adsorption/desorption analysis, that the ultrasound treatment causes substantial changes in the atomic and porous structure of the samples. The ultrasound treatment resulted in an increase of the graphitization degree of the carbon material and thus, in an increase of its density. The specific surface area and specific volume of the investigated samples decreased after the ultrasound treatment. The impedance dependencies for the supercapacitors made either from the initial and the modified carbon have been analyzed. The equivalent electrical circuits modelling the Nyquist diagrams have been constructed. De Levie impedance model, modified by series connection of parallel RC‐circuit, was used. It has been shown that ultrasonic radiation changes the Fermi level position by shifts to the energy region with high states density of delocalised electrons. This is the reason for unblocking of the Helmholtz layer capacitance due to the increase in the capacitance of the layer of the space charge region in the carbon material. It was shown that ultrasound treatment allows also controlling successfully the admixture and native defects distribution, existing on material surface and which are responsible for the surface electron states formation.</jats:p>

Topics

• porous
• density
• impedance spectroscopy
• surface
• Carbon
• Nitrogen
• defect
• ultrasonic