Diffusion-Controlled Electrosynthesis of Nanoporous Electrodes for Electrochemical Supercapacitors

Nanostructured manganese dioxide films were obtained by electrosynthesis using 0.02-0.15 M KMnO4 solutions. The diffusion-controlled deposition mechanism is based on the reduction of anionic MnO4- at the cathode surface. The method allowed the fabrication of porous films for application in electrochemical supercapacitors (ES). It was shown that film porosity is beneficial for the charge transfer during deposition, crack prevention in thick films and electrolyte diffusion in fabricated ES electrodes. Porous nanostructured films showed good capacitive behavior in the 0.1 M Na2SO4 electrolyte in a voltage window of 1V. The specific capacitance decreased with increasing scan rate due to the diffusion limitation in the porous manganese dioxide electrodes