Hierarchical NiMn Double Layered/Graphene with Excellent Energy Density for Highly Capacitive Supercapacitors

Abstract In the present article, highly capacitive NiMn-LDHs/GO composite of electrode material has been the synthesized for supercapacitor energy storage. Various analytical techniques (particularly X-ray diffraction (XRD), Raman spectroscopy, high resolution transmission electron microscopy (HRTEM), and scanning electron microscope (SEM)) have been employed to characterize the as-synthesized NiMn-LDHs/GO. The Microscopic images obtained using HRTEM analysis clearly reveal the formation of lattice fringe pattern (lattice spacing as ~ 0.22 nm) for GO, whereas SEM images shows highly porous nature. The super-capacitive performance of the as-synthesized electrode material have been accessed through an electrochemical work station comprising of a 3-electrode system. The working electrode made up of NiMn-LDHs/GO (Active material) on Ni foil (working electrode) with the help of PVDF (binder), has shown specific capacitance of 1964 F g−1 at current density of 1 A g−1 with Galvanostatic charging/discharging (GCD) technique. It has also shown remarkable cyclic stability with a capacitance retention of 98% after 2000 cycles. The high-power density (401 W/kg) and energy density (17.78 Wh/kg) signify the high-level electrochemical supercapacitor behaviour in charge storage applications.