Supercapacitors Based on Activated Carbon Xerogel and Manganese Dioxide

The use of alkali sulfates as electrolytes in supercapacitors eliminates the known limitations related to corrosion in aqueous electrolytes, but also it provides an opportunity to obtain high energy density, simultaneously being more eco-friendly and cost effective and safe [1]. In present work, the electrochemical characteristics of symmetric and hybrid supercapacitors based on synthesized manganese dioxide and activated xerogel (AX 6.5, pH = 6.5) were studied. In order to obtain a material with desired specific properties, the synthesis of activated carbon was carried out using microwave radiation where adjusting the pH, dilution ratio and resorcinol/formaldehyde (R/F) molar ratio. The cells are assembled in configuration using two electrodes without current collectors. Exchange AquavionTM commercial membrane with superior cation conductivity, chemical and thermal stability of up to 230 0C, is used as a separator and electrolyte. The structure, morphology and porous texture properties of electrodes materials are analyzed respectively by means of powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopes (TEM), and low-temperature nitrogen adsorption techniques. The electrochemical performances of the electrodes are determined by cyclic voltammetry, galvanostatic charge/discharge as well as long-term tests. The obtained results are encouraging and demonstrates a stable cycling performance of the studied MnO2/AX cell.