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In this work, the processes occurring in electrochemical systems based on nanoporous carbon material and manganese oxide in an aqueous solution of lithium sulfate are analyzed. Furthermore, it is shows the feasibility of these materials combination cycling as electrodes of a hybrid electrochemical capacitor. The combination of electrode materials with different mechanisms of charge accumulation was determined. Consequently, an increase in the accumulated energy by more than 25% by the formation of an electric double layer and the occurrence of redox reactions based on carbon and manganese oxide respectively. The laboratory sample of an aqueous electrolyte hybrid electrochemical capacitor was formed. Moreover, the laboratory sample is electrochemically stable at an operating voltage of 2 V.

In this work, the porous structure of the carbon material and the crystalline structure of manganese oxide α - modification (α - MnO2) have been investigated. The electrochemical performance of symmetric and asymmetric supercapacitors (α - MnO2 / Activated carbon) was investigated by cyclic voltammetry and galvanostatic cycling methods. The processes occur mainly at the electrode – electrolyte interface have been analyzed. It was determined that at discharge currents of 0.5 - 5 mA, the specific capacitance value for the α - MnO2 / Activated carbon hybrid capacitor exceeds the value of the symmetric capacitor by 45 - 55 % under the same conditions.

In this work, the morphological and electrical properties of the composite nanoporous carbon material/thermally expanded graphite or acetylene black have been investigated. Nanoporous carbon material was obtained from plant materials by its thermochemical activation based on potassium hydroxide. The dependence of the specific capacity of the nanoporous carbon/electrolyte electrochemical system on the applied potential was determined by the impedance spectroscopy method. Furthermore, the concentration of charge transfer and the density of states, as well as the flat-band potential of the system under research, were determined based on the Mott-Schottky model.