A g -1 , respectively. The NSCP, and NFBCP electrodes displayed the capacitance retentions of 82.1, and 83.2 %, which is lower than that of dual-heteroatom doping (NSCP and NFCP). The decreased capacitance retentions are due to the combination of B atoms with oxygen atoms on the carbon surface, which effectually lowered the electrical conductivity of the electrode materials. In 6M KOH electrolyte, the specific capacitance of NFBCP, NFCP, and NCP were 356. .4 F g -1 at 1 A g -1 , which is also almost similar to that of 1 M H2SO4 supercapacitor performances. However, the S doped carbons such as NSBCP, and NSCP exhibited 273.7, and 213. 3 F g -1 of specific capacitance at a current density of 1 A g -1 , which is well-below to that of 1 M H2SO4. The decrement in the specific capacitance values were attributed to less phenol or carboxyl type groups in the NSBCP, and NSCP, because they tend to occur faradaic reactions in proton-free KOH solution. The stability studies were conducted using NFBCP electrode in 1 M H2SO4 solution, which retained 100% of the initial capacitance after 10000 cycles. Further, a flexible all-solid-state supercapacitor (FSSC) was fabricated using NFBCP based electrodes, and the corresponding GCD experiments showed the maximum volumetric capacitance of 4.45 F cm -3 at 0.01 A cm -3 , and the device showed 79% capacitance retention after 10000 cycles. The FSSC device fabricated using NFBCP delivered the maximum volumetric energy density of 0.58 mW h cm -3 at a current density of 0.01 mA cm -3 , together the maximum volumetric power density of 46 mW cm -3 . Further, to investigate the practical applications, three FSSC devices were assembled in series with the 3V red LED and the charged assembled cell powdered a red light as shown in Fig. . the homogeneously dispersed Co9S8 anchored on N, and S co-doped carbon materials (CoS@NSC), derived by pyrolysis of natural soybeans treated with cobalt nitrate, KOH, and ammonium persulfate and developed as a bifunctional material for oxygen electrocatalysts, and supercapacitor applications . The catalysts were prepared at three different temperatures, such as 700, 800, and 900 ˚C and were abbreviated as CoS@NSC-700, CoS@NSC-800, and CoS@NSC-900, respectively. The SBET of CoS@NSC-700, CoS@NSC-800, and CoS@NSC-900 was calculated as 209, 350, and 357 m 2 g -1 , respectively, which demonstrated that the combination of thermal decomposition at high temperature, and KOH activation resulted to the high SBET of the carbon material. The XPS analysis of CoS@NSC-700, CoS@NSC-800, and CoS@NSC-900 revealed the O/N/S heteroatoms with 10.67/9.2/1.96, 8.14/5.31/1.82, 6.97/2.2/1.15 at.%, respectively. The heteroatoms contents were gradually decreased with increasing pyrolysis temperature. In 6 M KOH electrolyte, CoS@NSC-800 electrode displayed a maximum capacitance of 289 Fg -1 at 1 A g -1 , which was much higher than that of CoS@NSC-700 (230 F g -1 ), and CoS@NSC-900 (207 F g -1 ). Further, the CoS@NSC-800 demonstrated the capacitance retention of 80% after 10000 cycles. The At the current density of 0.5 A g -1 , the supercapacitive performance of CNS, and NCNS were tested in a three-electrode system using 0.5 M H2SO4 electrolyte. The CNS, and NCNS electrodes showed the specific capacitance of 82.5 F g -1 , and 166 F g -1 , respectively. The capacitive performances of CNS, and NCNS were compared with N-doped graphene (N-Gr)