Home – Home – Jornals – Chemistry for Sustainable Development 2017 number 6

With the common purpose of developing functional and cost-effective new electrode materials, including those for supercapacitors, a preparation method was elaborated and electrocapacitive properties of nanostructured composites based on a mesoporous carbon material filled with manganese oxides were examined. Carbon material used as a matrix of nanocomposites was produced by carbonization of naturally oxidised coal at 800 °С. Composites were obtained by reduction of potassium permanganate solutions with carbon matrix at 20-25 °С without the introduction of additional reducing substances. The content of Mn _x O _y in composites was varied from 1 to 5 mass %. Manganese oxides in nanocomposites were in the X-ray amorphous state, as demonstrated by powder X-ray diffraction technique. Nafion® ion exchange membrane was used as a separator, a 6 M KOH solution - as an electrolyte during studying electrochemical properties using Parstat 4000, potentiostat/galvanostat. The electric capacity of nanocomposite electrodes is higher than that of matrix-based electrode material, as demonstrated by methods of cyclic voltammetry in potential windows a) from -1.5 to 1.5 V; b) from -1 to +1 V; c) from 0.1 to 0.8 V), galvanostatic charge-discharge and electrochemical impedance spectroscopy. Internal resistance and total impedance of asymmetric cells with nanocomposite electrodes was less than appropriate values for the symmetric cell with electrodes based on matrix. The optimum content of manganese in composites was 3 %, as established. Herewith, the reached capacity for Mn _x O _y /C nanocomposite hybrid electrode material in a potential window from 0.1 to 0.8 V was 404 F/g when using a 6 M KОН aqueous solution as the electrolyte.