Fg -1 at a current density of 0.2 Ag -1 , while N, S-CN resulted in 138 F g -1 at 0. The electrode displayed a high-rate capability of 249.7 F g -1 at 30 A g -1 with a cycling stability of 99.5% at 1 A g -1 after 10000 cycles. The obtained higher specific capacitance values at 800 ˚C is attributed to the effective charge storage and transfer of electrolyte ions. The higher rate-capability of the electrode at is due to the rational distribution between micropores, and mesopores. Further, the symmetrical supercapacitor device was assembled in EMIMBF4 ionic liquid electrolyte, in order to improve the energy density. The assembled device delivered a specific capacitance of 51.9 F g -1 at 1 A g -1 , and showed the energy density of 22.1 W h Kg -1 at the power density of 875.0 W Kg -1 . The symmetric supercapacitor could able to retain 11.78 W h Kg -1 at a high-power density of 4376.5 W Kg -1 and possessed a long-term cycling stability with a capacitance retention of 99.5% after 10000 cycles. Thiourea was used as the source for nitrogen, and sulfur doping. N/S co-doped activated corncob sponge (N, S-ACS2:1) possessed the high accessible SBET of 1874 m 2 g -1 with a total pore volume of 0.945 cm 3 g -1 , and an average pore size of 1.880 nm. The XPS analysis confirmed the presence of N and S doping with 5.11, and 2.86 at%, respectively. The electrochemical measurements were performed in a three-electrode cell arrangement using 6