Ternary 3D reduced graphene oxide/Ni0.5Zn0.5Fe2O4/polyindole nanocomposite for supercapacitor electrode application (original) (raw)
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SN applied sciences, 2020
Graphene-metal frameworks have been extensively studied and developed as electrode materials for next generation energy storage materials. Their high surface area and easily transformable structure enhances its specific capacitance characteristics. In the present study, graphene oxide (GO) was synthesized using Hummers method. Zinc oxide and copper oxide nanoparticles were incorporated in to the GO matrix to form mixed metal oxides. GO, GO-CuO and GO-ZnO were characterized using UV-Visible, FTIR, FT Raman spectroscopy, SEM and XRD to confirm their effective formation. The surface of the glassy carbon electrode was modified by drop casting with the samples on its surface and its electrochemical properties were studied. Cyclic Voltammetry studies were conducted at various scan rates in different electrolytes (KCl, H 2 SO 4 and Na 2 SO 4) and the characteristic curves were observed to be asymmetric in nature. GO-CuO exhibits the highest specific capacitance of 790 F/g at 5 mV/s in KCl. The specific capacitance of the modified electrodes was also measured using the Chronopotentiometry technique. GO-CuO nanocomposites show a maximum specific capacitance of 800 F/g at 1 A/g. The nanocomposites showed enhanced electrochemical behaviour of the nanocomposites when compared to pure GO. The nanocomposites also showed good cycling stability. The superior performance of the GO-CuO and GO-ZnO nanocomposite electrode renders it as a promising material for supercapacitors applications.
ACS Sustainable Chemistry & Engineering, 2017
A simple, fast, and scalable mix-and-heat process was developed for production of three-dimensional (3D) porous graphene nanostructure. The process involves only mixing and heating of starch and a graphene oxide (GO) suspension at 90 o C for 10 min to form 3D graphene monoliths, from which a three-dimensionally well-connected porous graphene nanostructure, starch/RGO, possessing a high specific surface area of 1519 m 2 g-1 was obtained. The starch/RGO material was used as the electrode material to fabricate flexible, gel-type symmetric supercapacitors of outstanding capacitive performances, delivering a high energy density of 19.8 Wh kg-1 at the power density of 0.5 kW kg-1 and exhibiting an excellent high rate capability of a high power density of 9.9 kW kg-1 at the energy density of 9.6 Wh kg-1 , among the highest for pristine carbon material based gel-type, symmetric supercapacitors. The cycling stability of the starch/RGO based supercapacitor was excellent, with a high specific capacitance retention rate of 80% after 8000 cycles at 10 A g-1. The starch/RGO based supercapacitor exhibited outstanding mechanical stability with a retention rate of 90% in both energy and power densities at a large bending angle of 138 o and functioned well in a wide temperature range environment.
Electrochimica Acta, 2019
Asymmetric supercapacitor (ASC) devices are emerging as effective high-performance energy storage systems. We report on the synthesis of novel and green electrode materials and their use to construct high performance ASCs. The assembled ASCs are based on 3D porous graphene-wrapped V 2 O 5 nanospheres as the positive electrode and Fe 3 O 4 @graphene as the negative electrode. The optimal ratio of the V 2 O 5 nanospheres intercalated graphene sheets in the composite electrodes was identified. Compared to all positive electrode formulations, the V 2 O 5 @3DGr (33%) hybrid electrode achieved the highest specific capacitance (612.5 Fg −1) at a current density of 1.0 A g −1. Based on the excellent electrochemical behavior of the fabricated electrodes, the assembled asymmetric supercapacitor devices of V 2 O 5 @3DGr//Fe 3 O 4 @3DGr exhibited a maximum energy density of 54.9 Wh kg −1 with a power density of 898 Wkg −1 with an extended voltage of 1.8 V in 1.0 M Na 2 SO 4 aqueous electrolyte. Furthermore, the ASC device demonstrated excellent cycling stability with 89.6% capacitance retention over 10,000 cycles. The outstanding electrochemical performance of the fabricated electrodes can be attributed to the synergic effect between graphene sheets and metal oxides (V 2 O 5 , Fe 3 O 4) sandwich network structures. Interestingly, the proposed asymmetric electrode materials provide a promising strategy for integrating low cost transition metal, green electrolyte, high energy, and power densities of supercapacitor devices and that can bridge the gap with commercial batteries.
Keywords: Ternary hybrid nanocomposite RGO-(RuO 2 /CNCs) specific capacitance energy density cycle life A B S T R A C T Ternary nanocomposites have attracted increasing attention as efficient supercapacitor electrode materials. Here we report, the synthesis of a ternary hybrid nanocomposite by the introduction of crystalline RuO 2 nanoparticles loaded carbon nanocoils (CNCs) as spacers in reduced graphene oxide (RGO). The RGO-(RuO 2 /CNCs) composite electrode exhibits a high specific capacitance of 725 F g À1 at a scan rate of 20 mV s À1 in three-electrode configuration. When used in symmetric two electrode configuration, it shows a specific capacitance of 436 F g À1 at a constant current density of 1 A g À1 , which is nearly three times higher than that of pure RGO based electrode. An aqueous asymmetric supercapacitor fabricated using RGO-(RuO 2 /CNCs) as the positive electrode and RGO as the negative electrode is operational in an electrochemically stable potential window of 2 V. The asymmetric capacitor exhibits a high energy density of 45 Wh Kg À1 at a power density of 1 kW kg À1 and retains an energy density of 41 Wh Kg À1 even at a high power density of 40 kW kg À1 .
Electrode Materials for Supercapacitors: A Review of Recent Advances
Catalysts
The advanced electrochemical properties, such as high energy density, fast charge–discharge rates, excellent cyclic stability, and specific capacitance, make supercapacitor a fascinating electronic device. During recent decades, a significant amount of research has been dedicated to enhancing the electrochemical performance of the supercapacitors through the development of novel electrode materials. In addition to highlighting the charge storage mechanism of the three main categories of supercapacitors, including the electric double-layer capacitors (EDLCs), pseudocapacitors, and the hybrid supercapacitors, this review describes the insights of the recent electrode materials (including, carbon-based materials, metal oxide/hydroxide-based materials, and conducting polymer-based materials, 2D materials). The nanocomposites offer larger SSA, shorter ion/electron diffusion paths, thus improving the specific capacitance of supercapacitors (SCs). Besides, the incorporation of the redox-ac...
Heteroatom doped graphene based hybrid electrode materials for supercapacitor applications
Electrochimica Acta, 2018
A series of vanadium pentoxide (V 2 O 5 /G) nanocomposites with graphene and doped graphene was synthesized by a facile solvothermal route and the supercapacitor performance of the obtained mterials were further examined. The various heteroatom doped graphene composites viz. B doped (V 2 O 5 /BG), N doped (V 2 O 5 /NG) and BN codoped graphene (V 2 O 5 /BNG) was analyzed systematically to understand the effect of the dopants and their electrochemical properties. The structural and morphology of the obtained nanocomposites were investigated by using X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), Thermogravimetric Analysis (TGA) and Brunauer, Emmett and Teller (BET). The results showed that the prepared V 2 O 5 nanoparticles are deposited uniformly on graphene sheets. The electrochemical behavior of the nanocomposites were further analyzed to understand its supercapacitance properties in KOH electrolyte. A maximum specific capacitance of 1032.6 F/g was observed for V 2 O 5 /NG at 1 mVs-1 scan rate. Galvanostatic charge/discharge curves showed an excellent cyclic stability with higher charge/discharge duration with an energy density of 185.86 Wh/Kg and a power density of 37.20 W/Kg respectively for V 2 O 5 /NG nanocomposite. The graphene moieties provide fast and smooth electron transfer between V 2 O 5 materials, thus leading to higher electrode performance compared with V 2 O 5. The doping of heteroatom on graphene has been proven to be an effective way to tailor the properties of grpahene and render its potential use for supercapacitor electrodes.
Supercapacitors based on graphene/pseudocapacitive materials
Journal of the Serbian Chemical Society
Composites of graphene and SnO 2 were successfully prepared by a single step simultaneous synthesis of SnO 2 and reduction of graphene oxide (GO). Three different compositions of precursor solution resulted in different composite materials containing graphene and SnO 2. The reaction was realized by microwave-assisted hydrothermal synthesis. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) gave insight into the morphology and composition of the obtained materials. Good capacitive/ /pseudocapacitive properties of the obtained material suitable for supercapacitor application were registered by cyclic voltammetry, from where specific capacitance values up to 93 F g-1 were determined.
All graphene electrode for high‐performance asymmetric supercapacitor
International Journal of Energy Research, 2019
"Electrode imbalance" is one of the major issues that hinders the potential performance of asymmetric supercapacitors (ASCs), which arises mainly due to the huge dissimilarities of the electrodes microstructures. Herein, an "allgraphene" electrode system is designed by simple chemo-thermal modification of graphene oxide. Chemically functionalized graphene (FG) cathode and two anodes based on thermally reduced graphene oxide (TrGO) and iodine-doped graphene (IG) prepared via simple synthetic routes, followed by assembling into ASCs. The ASC comprising FG cathode-IG anode delivers phenomenally high energy-power (E-P) density (91 W h kg −1 and 424.95 W kg −1) and a good capacitance retention after 10 000 cycles. This outcome is accredited to the similar chemistry of electrodes resulting in a minimal electrode imbalance. The developed scheme has capacity to be employed as all-graphene hybrid energy storage system outputting enhanced performance and cyclic stability.
3D mesoporous reduced graphene oxide with remarkable supercapacitive performance
Carbon, 2019
Chemical reduction of graphene oxide (GO) to reduced graphene oxide (rGO) is an important process in view of the development of graphene-based supercapacitors on industrial level. We report an in situ chemical reduction of GO by copper(I) salt (CuCl) and isolation of semiconducting rGO material with three-dimensional (3D) mesoporous structure. Fabricated all solid-state supercapacitors of our rGO exhibited specific capfacitance and energy density values as high as 310 F/g at a current density of 1 A/g and 10 Wh/kg, respectively in an eco-friendly aqueous gel polymer electrolyte system. Furthermore, increasing the mass loading of rGO boosted the areal capacitance to a record value of about 580 mF/cm 2 at 1 mA/cm 2 current density. More than 80% capacitance was retained beyond 100,000 continued charge-discharge (CD) cycles. Also, sustainability of our rGO supercapacitor over switching current densities in the CD cycles was excellent resembling the rate performance in battery-like energy storing devices. The use of organic electrolyte boosted the energy density of rGO to very high level of ~22 Wh/kg.
The Journal of Physical Chemistry C, 2017
We have synthesized ternary rGO/Fe 3 O 4 /PANI (rGFP) composite for binder free, semiflexible, thin, all-solid-state supercapacitor devices fabrication. A scalable soft-template technique has been adopted for the preparation of three-dimensional Fe 3 O 4 decorated reduced graphene oxide (rGO) doped polyaniline (PANI) nanorods that are unambiguously investigated under electron microscopes (FESEM and HRTEM). The presence of PANI in the nanocomposite is overwhelmingly supported by the absorption and vibration studies, Raman spectra convincingly show the presence of rGO in the nanocomposites and the formation of Fe 3 O 4 nanoparticle is confirmed by XRD and XPS results. The specific capacitance value has been achieved for synthesized ternary rGFP nanocomposite is ~283.4 F/g at 1.0 A/g current density and exhibited maximum energy density 47.7 Wh/kg at the power density of 550 W/kg. Interestingly, after 5000 cycles the composite shows excellent life stability that is 78% retention of electrochemical property. To demonstrate the portable energy storage applicability, binder free rGFP based supercapacitor device was fabricated, which illustrated the operation of a LED bulb for 30 minutes when fully charged. These results are indicating that synthesized ternary nanocomposites are worth potential as electrode material and would be used in the next-generation high-rate energy storage systems.