The optimized N, P co-doped graphene monolith based symmetric supercapacitor attained an excellent electrochemical stability showing 94% retention in capacitance from its initial value over 10000 cycles at 5 A g -1 as displayed in Fig. maximum specific capacitance of 416 F g -1 at 1 A g -1 in 6 M KOH solution which was due to the fact that it has got the high SBET of 206.6 m 2 g -1 . The atomic percentage of both nitrogen and phosphorus derived from XPS analysis of the optimized material were found to be 5.66 and 6.48%, respectively. The 94.6 % of capacitance was retained after 10000 cycles and the symmetric supercapacitor investigations revealed that it has gained an energy density of 15.2 Wh Kg -1 in 6 M KOH solution.