Flexible asymmetric microsupercapacitor with high energy density based on all-graphene electrode system

The growing interest and rapid development of portable and flexible wearable electronics has significantly escalated the need of designing miniaturized on-chip energy storage and conversion units as power sources for smart electronic devices. Current aqueous microsupercapacitors suffer from a low energy density due to their small working potential, which limits their potential application. This study presents the fabrication of a 1.6 V flexible, aqueous asymmetric microsupercapacitor (AMSC) with 83% capacitance retention after 5000 cycles which designed by the integration and voltage balance of functionalized graphene-based cathode as a double-layer supercapacitive electrode and iodine-doped graphene anode as a pseudocapacitive electrode. The combination of electrostatic and faradic charge storage mechanism in this all-graphene-based AMSC enables the device to deliver an ultra-high energy–power density (4.75 mWh cm−3 at 61.55 W cm−3) and a stabilized performance even after 2000 repeated bending cycles, which suggests the promising potential of the all-graphene AMSC as a substantial power source for future flexible electronic devices.