A novel hydrothermal synthesis and characterisation of porous Mn3O4 for supercapacitors with high rate capability†
Abstract
Porous nanostructured Mn3O4 particles were successfully synthesized by a novel hydrothermal method via adding the surfactant hexadecyltrimethylammonium bromide (CTAB). They were characterized by the techniques of thermogravimetric and differential thermal analysis (TG/DTA), X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), and N2-adsorption. The electrochemical performance of the sample was studied by galvanostatic charge–discharge, cyclic voltammetry and electrochemical impedance spectroscopy in 1 M Na2SO4 aqueous solution electrolyte. It exhibits a high specific capacitance (232.5 F g−1 at 0.5 A g−1) and good rate capability (190 F g−1 at 5 A g−1), which can be attributed to its porous structure, the defects and vacancies on the surface. The capacitance retention reaches 78% after 5000 cycles at a current density of 5 A g−1. The results show that Mn3O4 has the potential to be used as the electrode material for a supercapacitor with high performance.