MnO2-based carbon nanofiber cable for supercapacitor applications

Abstract Supercapacitors (SCs) are an important option for energy storage. In this study, coaxial fiber cables with a 100-nm-thick manganese dioxide (MnO2) layer as the electrochemical active shell and 320-nm-diameter electrospun carbon nanofibers (CNFs) as the current-collecting core are fabricated. The MnO2 layer was electrodeposited onto the CNFs. The coaxial MnO2-CNFs cable mat was used for an SC study. A specific capacitance of 324.55 F/g was obtained at a current density of 0.5 A/g in 1 M Na2SO4 aqueous solution. The energy density and power density were 37.92 Wh/kg and 250 W/kg, respectively. The cable mat was assembled into a coin cell as a symmetric SC in 1 M Na2SO4 aqueous electrolyte. A specific capacitance of 47 F/g was achieved at 0.5 A/g with a potential window of 0 to 1.6 V. The binder-free and conductive-medium-free MnO2-CNFs cable mat is foldable and thus has potential for flexible SC devices.