Flexible asymmetric solid-state supercapacitor of boron doped reduced graphene for high energy density and power density in energy storage device

Abstract

Environment safe, cost-effective, reusable and portable asymmetric solid-state supercapacitor (ASSC) device, working at higher operating potential with high energy density was the challenging criteria for practical application. To satisfy all these we fabricated the ASSC device with boron doped reduced graphene (BRG) as positive and reduced graphene oxide as negative electrode with H2SO4/PVA solid gel electrolyte. Using three different precursors at different weight ratio of boric acid (HBG), boron powder (BG) and boron trioxide (BTG) boron doped reduced graphene oxide was prepared by hydrothermal treatment followed by pyrolysis at 1000 °C in CVD for 2 h. All electrode material exhibits a EDLC and pseudocapacitance in CV and GCD with high capacitance, HBG exhibits 225 Fg−1, BG shows 216 Fg−1 and BTG exhibits 266 Fg−1. Our BTG2//rGO ASSC device exhibits the specific capacitance of 122 Fg−1 with an energy density of 67.8 Wh Kg−1, also exerts an excellent stability of 94% capacitance retention with 99% of coulombic efficiency even after 5000 cycles. Using the device 5 mm red light emitting diode (LED) and DC motors was demonstrated for potential applications.