Flexible electronics have found a wide variety of novel applications such as flexible displays, flexible solar cells, flexible circuits, electronic papers, and touch screens. Recently, it can be seen that several studies have conducted to explore high density flexible energy storage devices for their potential applications in flexible electronics such as electronic displays, mobile phones, smart bands, health bands, laptops, and computers [ 1 ]. Heteroatom-doped graphene electrodes have found to be one of a promising candidates for high density flexible energy storage applications due to its dual nature of pseudo capacitance and electrochemical double-layer capacitance. Moreover, the low energy density supercapacitors limits its potential usage and the attempts are still in progress to overcome this problem. To augment for the high energy density of the supercapacitor device, the redox-additive electrolytes are believed to be one of the elite tactics. Here, they have reported on sodium...