Facile synthesis of Mn3O4 nanoparticles towards high performance asymmetric supercapacitors

In the present study, Mn3O4 nanostructured particles were prepared using a one-step hydrothermal method with varying different surfactants such as CTAB, PVA and EDTA, referred to as M-CTAB, M-PVA and M-EDTA, respectively. The structural properties were systematically studied using XRD, FTIR, SEM, TEM and XPS analysis. The electrochemical performance was assessed by CV, GCD and EIS measurements. The specific capacitance of the Mn3O4 electrodes was calculated using GCD at different current densities and CV at different scan rates. The specific capacitance values of the Mn3O4, M-CTAB, M-PVA and M-EDTA were 147.5, 156.5, 157.1 and 202.7 F g-1 at 5 mV s-1, 185.6, 209.5, 211.8 and 288.8 F g-1 at 0.5 A g-1. A superior capacitance retention of 99.4 % was observed for M-EDTA electrode even after 5000 continuous charge discharge cycles. An asymmetric supercapacitor (ASC) device made of M-EDTA//AC has a high energy and power densities of 36.9 Wh kg-1, 1043 W kg-1, respectively. Two ASC devices connected in series illuminated a red LED for 90 s. Thus, the M-EDTA can be regarded as promising electrode material for asymmetric supercapacitors.