Investigation of thin sputtered Mn films for electrochemical capacitors

Pseudocapacitive manganese oxide films have been synthesized by anodic oxidation of metallic films deposited by sputtering. Results are presented from an electrochemical investigation into properties of these thin sputtered manganese films. Mn films with thickness ranging from 20 to 200 nm have been sputtered onto Pt coated Si wafers in an Argon atmosphere. Electrochemical oxidation converts the metal film into a porous, dendritic structure which displays significant pseudocapacitance. We have observed a specific capacitance (C-s) of 700 F/g when cycled very slowly at a constant current density of 160 muA/cm(2). The same films probed by cyclic voltammetry (CV) at a rate of 5 mV/s yielded a lower specific capacitance of 400-450 F/g. Post-oxidation material loading was measured to be in the range of 25-75 mug/cm(2). (C) 2004 Elsevier Ltd. All rights reserved.