Iron oxide induced preparation of nanoscrolls of reduced graphene oxide for electrochemical charge storage applications

Fe₃O₄ - reduced graphene oxide nanoscrolls (FRGNS) are tailored for fabricating electrode material for supercapacitor applications. The scrolling of reduced graphene oxide is initiated by the magnetic field produced by the superparamagnetic iron oxide NPs. The formation mechanism and critical concentration of nanoparticles required for scroll formation is investigated by varying the weight ratio of iron oxide NPs. The nanoscroll formation is completely reversible and reproducible. The unique end open morphology of nanoscrolls facilitates the electrolytic accessibility and the Fe₃O₄ NPs favor the redox reactions as well. At a current density of 1Ag^-1, FRGNS12 (rGO: Fe₃O₄ 1:12) achieve a noteworthy specific capacitance value of 1498 Fg^-1 within a potential ranging from 0 to −0.73 V in 1 M Na₂S₂O₃ with exceptional energy density of 110.9 Wh Kg⁻¹ and power density of 405 Wkg^-1. A prominent cycling stability of 88% capacitance retention after 4000 cycles is also obtained. The electrochemical performance of opened as well as regenerated scrolls (RFRGNS12) are also evaluated. The specific capacitance increases to 1514 Fg^-1 for RFRGNS12 due to the further exfoliation of rGO sheets take place during the unscrolling and scroll regeneration process. The unique fabrication methodology for the synthesis of graphene nanoscrolls and their utilization as electrode material for supercapacitors paves a new pathway for the advancement of novel electrode materials for supercapacitors.