Template-free preparation of vertically-aligned Mn 3 O 4 nanorods as high supercapacitive performance electrode material

Abstract Pulsed base (OH − ) electrogeneration was applied to the cathodic electrodeposition of manganese oxide from chloride bath for the first time, and Mn 3 O 4 nanorods were prepared. The deposition experiments were performed under a pulse current mode in a typical on-times and off-times (t on = 10 ms and t off = 50 ms ) at a peak current density of 1 mA cm − 2 (I a = 1 mA cm − 2 ). The structural characterizations with XRD and FTIR revealed that the prepared sample is composed of tetragonal crystal phase of Mn 3 O 4 . Morphological evaluations by SEM further proved that the prepared Mn 3 O 4 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 Mn 3 O 4 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.