CuMnO2-reduced graphene oxide nanocomposite as a free-standing electrode for high-performance supercapacitors

Abstract

Free-standing electrodes have attracted wide attention for advanced supercapacitors. Herein, direct deposition of CuMnO 2 and CuMnO 2-reduced graphene oxide (rGO) nanocomposite on nickel foam (NF) substrates was performed through a simple hydrothermal process. The simultaneous deposition makes full use of the synergistic effect formed by the large pseudocapacitance of CuMnO 2 and excellent electrical conductivity of rGO, which results a greater performance improvement of the nanocomposite comparing with that of bare CuMnO 2. Remarkably, the CuMnO 2-rGO/NF electrode displays a large specific capacitance of 1727 F g-1 at 3 A g-1 and manifests exceptional cycling stability with a retention ratio of 125% of the initial capacitance over consecutive 5000 cycles. Furthermore, a rGO/NF//CuMnO 2-rGO/NF asymmetric supercapacitor exhibits great electrochemical performance by delivering high energy density (37.5 Wh kg-1) and high power density (4250 W kg-1) as well as excellent cycling stability (3.3% decay after 4000 cycles). The presented results suggest that CuMnO 2-rGO nanocomposite can be considered as a potential candidate for highly stable and high-rate supercapacitors.

Green synthesis of nickel‐manganese/polyaniline‐based ternary composites for high‐performance supercapattery devices

“…For the ideal supercapacitor, the b should be equal to 1 and for pure battery‐grade materials, it should be equal to 0.5. The range of b value between 0.5 and 1 depicts the hybrid nature of device 77‐79 . The b values are obtained by linear fitting of CV curve of the device illustrated in Figure 10A.…”

High-performance freestanding supercapacitor electrode based on polypyrrole coated nickel cobalt sulfide nanostructures

“…The diffusion controlled and surface capacitive charge storage mechanisms contribute to the total capacitance of NiCo 2 S 4 @PPy/NF. The current dependency on the scan rate, ν, is determined by the following equation in theory 29 : where ‘ a ’ and ‘ b ’ are adjustable parameters, i is the current and v is the scan rate. When b = 1, the surface capacitive process is the dominant mechanism of charge storage; otherwise, when b = 0.5, diffusion-limited processes govern the current density (battery-type behavior).…”

“…Lately, transition metal sulfides including NiS, CuS, Co 9 S 8 , and NiCo 2 S 4 have been found to be promising electrode materials for faradaic electrochemical capacitors 25 – 27 . Amongst ternary Ni-Co sulfides, NiCo 2 S 4 has attracted increasing attention as a new material in supercapacitors, because of its better electronic conductivity and higher capacity compared to nickel and cobalt sulfide, and oxide 28 , 29 . Numerous nanostructures of NiCo 2 S 4 with different morphologies such as nanowires, nanotubes, and nanosheets arrays can be synthesized and deposited or directly grown on the conductive substrates, showing remarkable cycling stability 30 – 32 .…”

Graphitic Carbon Nitride Doped Copper–Manganese Alloy as High–Performance Electrode Material in Supercapacitor for Energy Storage

“…Specific capacitance (C S ), power density (P), plus energy density (E) are received from the galvanostatic discharge arcs conferred by the subsequent equations [35]:…”