In this study, a supercapacitor cathode electrode material was produced by recycling the black mass from spent Li-ion batteries, utilizing nickel, cobalt, and manganese compounds recovered from the recycling process. During the leaching process of the black mass powder, H2SO4 and a fixed 10 vol% H2O2 solution were used as the leaching medium. The effects of different acid molarities and leaching durations on the leaching efficiency were investigated. Cobalt/nickel/manganese hydroxide (CNMOH) and cobalt/nickel/manganese oxide (CNMO) were synthesized through conversion and used as cathode electrode materials in asymmetric supercapacitors. The areal capacitance values of CNMOH and CNMO electrodes were determined as 1219 mF/cm2 and 333 mF/cm2 at a scan rate of 5 mV/s in three elecrode system. The areal and spesific capacitance of the CNMOH//G coin-cell asymmetric supercapacitor at a scan rate of 5 mV/s were determined to be 252 mF/cm2 and 50.8 F/g respectively. The areal and spesific capacitance of the CNMO//G coin-cell asymmetric supercapacitor were also found as 223.17 mF/cm2 and 50 F/g respectively. Additionally, at a current density of 1 mA/cm2, the energy density of 7 Wh/kg and power density of 334.35 W/kg for CNMO//G supercapacitor and the energy density of 8.78 Wh/kg and power density of 263.09 W/kg for CNMOH//G supercapacitor were calculated. After 10,000 cycles, both CNMOH//G and CNMO//G supercapacitors retained more than 100 % of their initial capacitance.
