A redox-additive electrolyte for cobalt-manganese-layered double hydroxides-based asymmetric supercapacitor

A cobalt-manganese-layered double hydroxide (CoMn-LDH), the extremely desired electrode material in supercapacitors, has been synthesized via a one-step hydrothermal technique. The XRD analysis confirmed the formation of the CoMn-LDH. The nanorod-shaped surface morphology is revealed from the scanning electron microscopy and transmission electron microscopy analysis. The asymmetric supercapacitor has been constructed by employing activated carbon as anode material and CoMn-LDH as cathode material. The electrodes have been investigated in the mixed electrolyte comprised of potassium hydroxide and potassium ferricyanide. The fabricated supercapacitor with the two-electrode system delivers the highest specific capacitance of 30 F/g at 1 mA along with the highest energy and power density of 6 Wh/kg and 1400 W/kg. Furthermore, the electrodes demonstrate high capacity retention of 81.25% at a high current density of 5 mA after 1000 cycles.