Supercapacitive Performance of SILAR Grown Mn3O4 Nanoclusters: Effect of Cationic Precursor Concentration

Herein, we have investigated the effect of cationic precursor (manganese chloride tetrahydrate) concentration on the electrochemical performance of successive ionic layer adsorption and reaction (SILAR)-deposited Mn3O4 thin films. The concentration of the cationic precursor was varied from 0.05 to 0.15 M, and its effect on physicochemical and electrochemical properties was studied. X-ray diffraction and X-ray photoelectron spectroscopy analyses confirmed that Mn3O4 has a tetragonal structure with Mn2+ and Mn3+ oxidation states. SEM micrographs revealed that nanoclusters of Mn3O4 with an average size of similar to 200 nm were formed. Moreover, transmission electron microscopy analysis revealed that these nanoclusters were formed from tiny square nanoplates with a size of similar to 40 nm. Electrochemical studies of the synthesized Mn3O4 thin films were recorded in a three-electrode system, which suggests that 0.1 M cationic precursor concentration has a good electrochemical signature with a specific capacitance of 470 F/g at 1 mA/cm(2) current density in 1 M Na2SO4 aqueous electrolyte. The cyclic stability offered was appreciable, with capacitive retention of 75% up to 10,000 CV cycles scanned at 100 mV/s. The charge storage kinetics of the SILAR-grown Mn3O4 thin film were investigated. With systematic study we concluded that, the molarity of the cationic precursor plays a vital role in the porosity and microstructure which drastically affects the electrochemical performance.