Electrosynthesis and characterization of nanostructured MnO2 deposited on stainless steel electrode: a comparative study with commercial EMD

The nanostructured MnO2 powder was successfully synthesized by electrodeposition on stainless steel (SS) substrate from hot 0.3 M MnSO4 center dot H2O aqueous solution with pH value adjusted to 2. The electrochemical behavior of synthesized MnO2 was compared to that of the commercial electrolytic manganese dioxide (EMD). The investigation was conducted using a new cell which is manufactured in our laboratory. This gave us the possibility to present a new contribution and an improvement in the study of MnO2 electrochemical behavior. The analysis of the synthesized MnO2 and EMD powders by different techniques: FEG-SEM, EDS, TEM, XRD, and BET revealed the presence of electrodeposited nanostructured gamma-MnO2 with high specific surface area of 139.59 m(2) g(-1) for the nanostructured MnO2 and 46.60 m(2) g(-1) for EMD. The electrochemical study of these powders conducted by linear voltammetry, electrochemical impedance spectroscopy (EIS) measurements, and Zn/MnO2 battery tests in 0.1 M NH4Cl electrolyte showed that the performance of the synthesized nanostructured MnO2 powder was higher than that of the commercial EMD powder.