Highly flexible reduced graphene oxide@polypyrrole–polyethylene glycol foam for supercapacitors

A flexible and free-standing 3D reduced graphene oxide@polypyrrole-polyethylene glycol (RGO@PPy-PEG) foam was developed for wearable supercapacitors. The device was fabricated sequentially, beginning with the electrodeposition of PPy in the presence of a PEG-borate on a sacrificial Ni foam template, followed by a subsequent GO wrapping and chemical reduction process. The 3D RGO@PPy-PEG foam electrode showed excellent electrochemical properties with a large specific capacitance of 415 F g-1 and excellent long-term stability (96% capacitance retention after 8000 charge-discharge cycles) in a three electrode configuration. An assembled (two-electrode configuration) symmetric supercapacitor using RGO@PPy-PEG electrodes exhibited a remarkable specific capacitance of 1019 mF cm-2 at 2 mV s-1 and 95% capacitance retention over 4000 cycles. The device exhibits extraordinary mechanical flexibility and showed negligable capacitance loss during or after 1000 bending cycles, highlighting its great potential in wearable energy devices.