Polyaniline (PANI)/graphene fibers have been recognized as promising candidate for flexible electronics owing to their excellent flexible, mechanical and electrochemical properties. Their fabrication usually involved two procedures: wet spinning of graphene-based fibers with different coagulants and chemical deposition of PANI with different oxidants. Here, Fe(III) ion-mediated fabrication strategy was established as a green approach for flexible fiber supercapacitor, based on its multiple effects: coagulant in the wet spinning and catalyst in the chemical oxidation polymerization of aniline (ANI) with air, as well as the redox additive in the final fiber electrodes. As results, rEGO/Fe@PANI fiber was obtained for the flexible symmetrical fiber supercapacitor, possessing superior electrochemical performance than the reported flexible PANI/graphene fiber supercapacitors, i.e. high capacitance of 10.48 mF/cm and power density of 604.10 mW/cm at energy density of 400 μWh/cm, good capacitance retention of 90 % after 10,000 cycles and 93.1 % after extreme deformation even at 180°-folding. Such performance makes it promising candidate for the future wearable flexible electronic devices.
