On the Effects of Electrolyte on the Capacitive Bbehavior of Nanostructured Molybdenum Oxides

Nanostructured molybdenum oxide was potentiodyanamically deposited onto a stainless steel surface from an aqueous bath by cycling the potential between 0 and -0.75 V vs. Ag/AgCl. The deposit consisted of particulates in the range of 30 to 80 nm. Electrochemical studies under galvanostatic charge/discharge and also impedance spectroscopy revealed capacitive behavior in the potential range of -0.3 to -0.55 V vs. Ag/AgCl with the value of 477 Fg-1 at 0.1 mA/cm2 in a solution of H 2SO4 and Na2SO4. Also, a capacitive behavior was observed in H2SO4 solution which depends to acid concentration. An equivalent circuit comprising of three parallel branches consisting of double layer capacitance, Warburg impedance and a constant phase element signifying pseudo-capacitance each coupled with their corresponding resistances was fitted to the experimental findings and the magnitudes of the elements were derived.

Keywords:

Nanostructure , Molybdenum Oxide , Supercapacitor