Template-free preparation of vertically-aligned Mn3O4 nanorods as high supercapacitive performance electrode material

Pulsed base (OH−) electrogeneration was applied to the cathodic electrodeposition of manganese oxide from chloride bath for the first time, and Mn3O4 nanorods were prepared. The deposition experiments were performed under a pulse current mode in a typical on-times and off-times (ton = 10 ms and toff = 50 ms) at a peak current density of 1 mA cm− 2 (Ia = 1 mA cm− 2). The structural characterizations with XRD and FTIR revealed that the prepared sample is composed of tetragonal crystal phase of Mn3O4. Morphological evaluations by SEM further proved that the prepared Mn3O4 is made up of large scale and vertically aligned one-dimensional (1D) nanorods with uniform shapes and an average diameter of 50 nm. The electrochemical measurements through cyclic voltammetry (CV) and charge-discharge techniques revealed that the prepared Mn3O4 nanorods have an excellent capacitive behavior, with the specific capacitances as high as 321, 292, 264, 222, 187 and 132 F g− 1 at the scan rates of 2, 5, 10, 25, 50 and 100 mV s− 1, respectively. The excellent long-term cycling stabilities of 91.7%, 83.4%, and 75.7% were also observed after 1000 charge-discharge cycles at the current densities of 1, 5 and 10 A g− 1, respectively.