Hence it has been realised that the performance of material towards supercapacitor application is determined by the synthesis methodology. Motivated by the earlier report, the same group studied the electrochemical capacitance of N-doped graphene by supercritical method using ammonium oxalate as the nitrogen source . The synthesis of N-doped graphene was performed with three various weight ratios of dopant and GO. Among the three different combinations, the N-doped graphene (AOGO-(1:2)) in which ammonium oxalate and GO are in the weight ratio 1:2 has delivered the highest specific capacitance of 274 F g -1 at 1 A g -1 in 20% KOH solution as the electrolyte and higher than RGO (182 F g -1 ). This is also evidenced by the fact that the nature of CV profile of N-doped RGO is broad while that of RGO is typical rectangular implying that the capacitance of N-doped RGO is higher than RGO as observed from Fig. and. The substantial increment in the capacitance was attributed to the transformation of pyridinic nitrogen into pyridine-N-oxide in alkaline medium. Also, the capacitance is enhanced due to the availability of oxygen containing substituents as the phenolic and carboxylic acid interacts with hydroxide ion to produce the oxyanion. When the quantity of GO is more, then it ends up with more amount of RGO which enhance the conductivity of the electrode. It was reported that the 90% of capacitance retained of its original value after 10000 cycles at 10 A g -1 as observed from Wh kg -1 ). Similarly, the benzimidazole derived N-doped graphene based symmetric supercapacitor has attained the energy density of 30 Wh kg -1 in EMIMBF4 electrolyte at 0.2 A g -1 which is appreciably greater than1 M TBABF4 in acetonitrile (13.8 Wh kg -1 ). This is attributed to the fact that the diameter of EMIM ion (0.76 nm) is lower than that of TBA ion which evidently suggests that the accessibility of ions towards electrode is more pronounced when the size of ion is smaller. More interestingly, Sandhiya et al. prepared the Ndoped graphene by supercritical method in different weight ratios of GO and the ammonium bicarbonate as the precursor and investigated the electrochemical performance of N-doped graphene as a flexible device using sodium tetramolybdate as the redox additive electrolyte . The calculated specific capacitance of N-doped graphene by three-electrode assembly was found to be 555 F g -1 at 1 A g -1 in 1 M H2SO4 which is appreciably superior than RGO (170 F g -1 ). The energy density of the symmetric cell was found to be 23 W h Kg -1 in 0.01M Na2MoO4/H2SO4 which is higher than 1M H2SO4 without redox additive (13 Wh Kg -1 ). Also, the fabricated flexible supercapacitor device with (Na2MoO4/PVA/H2SO4) gel electrolyte produced the energy density of 24 Whkg -1 which is 3.4-fold higher compared to a device having PVA/H2SO4 gel electrolyte (E = 7 Whkg -1 ) without redox additive. F g -1 , respectively. As the proton adsorption is no longer feasible in alkaline medium, the capacitance performance of N-doped graphene in acidic electrolyte is higher than alkaline medium. Then the additional pseudocapacitance in N-doped graphene in acidic electrolyte is attributed to the enhanced redox interactions between pyrrolic/pyridinic Nitrogen and H + ions from the acidic electrolyte. found to be 265 F g -1 at 1 A g -1 in 1 M TEABF4/ACN (acetonitrile) which is larger than RGO (155 F g -1 ) which might be due to the value of SBET of former is 1007 m 2 g -1 is appreciably greater than the latter (793 m 2 g -1 ). Additionally, the electrical conductivity of N-doped RGO was found to be 1532 S m -1 which is two-fold higher than RGO (704 S m -1 ). Moreover, the high-surface area N-doped RGO exhibits an ultrahigh energy density of 91 Wh Kg -1 as well as greater stability with the 96% of capacitance retained after 100000 cycles. In another literature, (100 and 300 seconds). It was found that the specific capacitance increases with increase in microwave irradiation period. Finally, the sample obtained in digestion tank about 400 seconds contained the N-doping level of 1.9 wt. % along with the maximum specific capacitance of 97 F g -1 at 5 mV s -1 in 1 M H2SO4. This was further validated by the fact that the Rct of the Ndoped graphene formed under 400 seconds was found to be 40.75 Ω which is the lowest among the three. does not have nitrogen (17.9 mF cm -2 ) in 1 M Na2SO4 solution. An impressive stability with 98.7% of capacitance after 25000 cycles at 10 mA cm -2 was achieved and displayed in Fig. . The increased behaviour towards energy storage is due to the higher nitrogen content as well as enhanced contribution from pyrrolic nitrogen that enhances the pseudocapacitance. KOH solution and 93.1% of capacitance retained after 3000 cycles at 2 A g -1 . Two-electrode studies revealed that it has delivered the energy density of 4.76 W h kg -1 along with 92.3% of retention of capacitance from its starting value after 5000 cycles at 0.5 A g -1 .