Enhanced supercapacitive performance of electrophoretically deposited nanostructured molybdenum-doped Mn3O4 thin films

Nanostructured molybdenum (Mo)-doped Mn3O4 thin films were successfully deposited on stainless steel substrates by a facile electrophoretic deposition technique. The effect of Mo doping on the structural and supercapacitive properties of Mn3O4 thin films was investigated. The nanostructured morphology of spinel tetragonal Hausmannite Mn3O4 thin films was elucidated with the help of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and Raman studies. The presence of mesopores in the nanostructure with an average pore size of 41 nm was confirmed by Brunauer-Emmett-Teller studies. The different valence states of Mn and Mo are confirmed by X-ray photoelectron spectroscopy. The symmetrical quasi-rectangular-shaped cyclic voltammetry curves without any redox peak and nearly triangular/symmetric galvanostatic charge-discharge curves for Mn3O4 thin films elucidated the pseudocapacitive behavior. Electrochemical impedance spectroscopy revealed that pure and Mo-doped Mn3O4 thin films have lower resistances. Improved supercapacitive performance of 2 % Mo-doped Mn3O4 thin film was confirmed by higher specific capacitance 497 F g-1 at a current density of 1.6 A g-1. The boosted supercapacitive performance of Mo-doped Mn3O4 thin films has identified the outstanding incorporation of Mo ions into the Mn3O4 lattice.