Waste to wealth: A sustainable and flexible supercapacitor based on office waste paper electrodes

In order to develop a low cost, sustainable, and eco-friendly energy storage device, we demonstrated an all solid state symmetric flexible supercapacitor based on the office waste paper fibers-reduced graphene oxide-manganese dioxide (PF-RGO-MnO 2 ) which acts as both the positive and negative electrodes. With the assistance of facile solution phase assembly and vacuum filtration method, the flexible PF-RGO-MnO 2 electrodes with high physical flexibility and excellent mechanical strength were fabricated directly without any binder agents. Furthermore, owing to the advantages of the lager surface area and microfibers of the each single paper fiber, the PF-based hybrid flexible electrodes show high specific capacitance of 410   F   g −   1 at 0.8   A   g −   1 and retain 93% capacitance over 5000 cycles, indicating outstanding electrochemical performance. In addition, the assembled solid-state symmetric supercapacitors exhibit high energy density (19.6   Wh   kg −   1 at 400   W   kg −   1 ) and excellent cycling stability of 85.3% retention even after 2000 folding and bending cycles. These results propose a renewable way to turn “waste” into wealth, and provide a new method to fabricate the sustainable and freestanding paper-based supercapacitor for application in the flexible energy storage devices.