Fig. graphene is found to be 116 F g -1 at 1 A g -1 which is two-fold higher than RGO (58.8 F g -1 ) which is because of the fact that the SBET of S-doped graphene (99.1 m 2 g -1 ) is greater than RGO (56.3 m 2 g -1 ). Importantly, the same has achieved the excellent energy density of 100 Wh Kg -1 at power density of 5000 W Kg -1 .