Preparation of an efficient electrode material for chemical energy storage devices by microwave carbonization and physical activation of tea biomass

Abstract

This work is intended to study and use carbon material obtained from tea leaf waste in energy storage systems. Microwave carbonization accompanied by physical activation in a CO₂ atmosphere was used as a synthesis method. Silicon carbide was used to increase the heating efficiency to ensure uniform heat distribution in the reaction zone. The obtained activated carbon is characterized by a porous structure and good electrical conductivity. The structural and morphological properties of the samples were studied by X-ray diffraction analysis, scanning electron microscopy and Raman spectroscopy. The electrochemical characteristics were evaluated by cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy. The ФА-30 sample showed high specific capacitance (up to 152 F/g) and high stability during long-term cycling - after 3000 cycles it retained more than 75% of the initial capacity. Electrochemical impedance spectroscopy analysis showed that the porous structure of the material has a low series resistance of about 1 Ohm and a very low charge transfer resistance, which indicates good ion conductivity and fast electrochemical processes. The results obtained prove that the prepared material is promising for use in supercapacitor electrodes.