Ag incorporated Mn3O4/AC nanocomposite based supercapacitor devices with high energy density and power density

Abstract

Silver incorporated Mn₃O₄/amorphous carbon (AC) nanocomposites are synthesized by a green chemistry method. X-ray diffraction studies revealed the structural changes in Mn₃O₄/AC nanocomposites attributable to the addition of silver. Cyclic voltammetry, charge–discharge and ac-impedance studies indicated that the Ag-Mn₃O₄/AC-5 electrode was the most suitable candidate for supercapacitor applications. From the galvanostatic charge–discharge studies, a higher specific capacitance of 981 F g⁻¹ at a specific current of 1 A g⁻¹ was obtained. An Ag-Mn₃O₄/AC-symmetric supercapacitor consisting of an Ag-incorporated Mn₃O₄/AC composite as an anode as well as a cathode, and an asymmetric supercapacitor consisting of an Ag-incorporated Mn₃O₄/AC composite as a cathode and an activated carbon as an anode have been fabricated. The symmetric device exhibits a specific cell capacitance of 72 F g⁻¹ at a specific current of 1 A g⁻¹ whereas the asymmetric device delivers a specific cell capacitance of 180 F g⁻¹ at a high current rate of 10 A g⁻¹. The asymmetric supercapacitor device yields a high energy density of 81 W h kg⁻¹. This is higher than that of lead acid batteries and comparable with that of nickel hydride batteries.