manganese dioxide, nanoparticles, self-assembly, nanostructured thin films
Self-assembled manganese dioxide thin films were being deposited directly onto metalized plastic supporting substrates by a novel horizontal submersion process which entailed spontaneous self-assembly of preformed manganese dioxide nanoparticles under optimized deposition conditions. Desired film thicknesses were obtained simply by repeating the deposition process after the prior deposited layer had been air-dried completely. Scanning electron micrographs had revealed that such self-assembled manganese dioxide thin films were nanoparticulate and highly porous in nature. Thin films with tailored microstructure were prepared through optimizing deposition conditions such as duration of submersion, temperature, pH, concentration and ionic strength of colloidal suspension, as well as the post-deposition calcination temperature. These films were shown by Cyclic Voltammetry to exhibit excellent capacitive behavior, and high cycling stability and reversibility within the potential range of 0.0 to 1.0 V (versus SCE) both in mild aqueous and gel electrolytes. The high pseudocapacitance was attributed to redox reactions involving homogenous intercalation and deintercalation of protons into and out of the oxide matrices during charge and discharge. Performance evaluation of ‘proof-of concept’ prototypes had indicated high potential utility of such nanostructured manganese dioxide thin films as novel electrode material for the fabrication of high energy and power density thin-film supercapacitors.