One-step electrochemical preparation and characterization of nanostructured hydrohausmannite as electrode material for supercapacitors

Abstract

A novel, simple one-pot electrochemical procedure is proposed for the preparation of hydrohausmannite. The deposition experiments were performed in manganese chloride bath under a galvanostatic mode, applying a current density of 2 mA cm⁻² (I_a = 2 mA cm⁻²). The structural characterizations with XRD and FTIR revealed the prepared sample to be composed of mixed Mn₃O₄ and MnOOH phases which is known as hydrohausmannite. Morphological evaluations by SEM and TEM further proved that the prepared sample had a nanoscale particle/plate morphology and the electrochemical measurements through cyclic voltammetry (CV) and charge–discharge techniques revealed that the prepared hydrohausmannite had an excellent capacitive behavior, with the specific capacitance values of 232, 209, 184, 133, 99 and 89 F g⁻¹ were calculated at the scan rates of 5, 10, 20, 50, 100 and 125 mV s⁻¹, respectively. An excellent long-term cycling stability of 92% was also observed after 1000 charge–discharge cycles.