Abstract:

One porous stainless steel-supported manganese dioxide thin film electrode, fabricated by electrochemical method was evaluated as a potential electrode for electrochemical capacitors. The porous stainless steel substrate electrode was obtained by mask electrolysis in the sodium chloride solution containing a lyotropic liquid crystalline phase of p-tert-alkylphenoxy poly(oxyethylene) ether(Triton X-100). Manganese dioxide film was electrodeposited on porous stainless steel substrate under a potentiostatic mode. Liquid crystalline phases were examined using XP-330C polarizing microscope at room temperature. The surface morphologies of the electrode were characterized by SEM. The capacity of manganese oxide film electrode was investigated by cycle voltammetry and constant-current charge-discharge method in potassium sulfate solutions. The results showed that stainless steel exhibited a highly porous surface morphology with an irregular pore size in a range of tens nanometer to hundreds nanometer after electrochemical erosion with liquid crystal mask. The deposited manganese oxide film consisted of spherical particles with an average size of 80~90 nm. The manganese oxide film electrode presents a specific capacitance of 400 F/g when the charge consumed is 0.4 C/cm2 in electro deposition. The highest capacitance of 320×10-3 F/cm2 could be obtained by cycle voltammetry at a scan rate of 20 mV/s, corresponding to a specific capacitance of 200 F/g. The porous stainless steel-supported manganese dioxide electrode shows promising applications in electrochemical super capacitors.

Key words: electrochemical capacitor, porous electrode, electrodeposition, manganese dioxide, liquid crystal mask