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1.
In this study, graphene oxide (GO) is chemically reacted with sodium borohydride (NaBH4) to form reduced graphene oxide (rGO). rGO, polycarbazole (PCz)/rGO and PCz/nanoclay/rGO materials were obtained by chemical polymerisation method. These three materials were characterised by Fourier-transform infra-red spectroscopy-attenuated transmission reflectance, scanning electron microscopy, energy-dispersive X-ray analysis, cyclic voltammetry (CV), galvanostatic charge–discharge and electrochemical impedance spectroscopy. The PCz/nanoclay/rGO nanocomposite shows significantly improved capacitance (Csp?=?187.78?F?g?1) compared to that of PCz/rGO (Csp?=?74.18?F?g?1) and rGO (Csp?=?20.78?F?g?1) at the scan rate of 10?mV?s?1 by CV method. The supercapacitor device performance results show high power density (P?=?1057.81?W?kg?1) and energy density (E?=?1.7?Wh?kg?1) obtained from Ragone plot for PCz/nanoclay/rGO material. Stability tests were also examined by the CV method for 1000 cycles.  相似文献   

2.
ABSTRACT

In this study, graphene oxide (GO) was chemically reacted with sodium borohydride (NaBH4) to form reduced graphene oxide (rGO). rGO, Montmorillonite nanoclay, and polyvinylcarbazole (PVK) were used to form a ternary nanocomposite via chemical reaction. These nanocomposite qualities were described via scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy-attenuated transmission reflectance (FTIR-ATR). In addition, these materials were used in supercapacitor device as an active material to test electrochemical performances via cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS). The rGO/nanoclay/PVK nanocomposite shows significantly improved specific capacitance (Csp = 168.64 Fg?1) compared to that of rGO (Csp = 63.26 Fg?1) at the scan rate of 10 mVs?1 by CV method. The enhanced capacitance results in high power density (P = 5522.6 Wkg?1) and energy density (E = 28.84 Whkg?1) capabilities of the rGO/nanoclay/PVK nanocomposite material. The addition of nanoclay and PVK increased the specific capacitance of rGO material due to a dopant effect for supercapacitor studies. Ragone plots were drawn to observe energy and power density of supercapacitor devices. The Csp of rGO/nanoclay/PVK nanocomposite has only 86.4% of initial capacitance for charge/discharge performances obtained by CV method for 5000 cycles.  相似文献   

3.
Polypyrrole/multi-walled carbon nanotube, poly(3,4-ethylenedioxythiophene)/multi-walled carbon nanotube and their nanocomposites P(EDOT-co-Py)/multi-walled carbon nanotube and P(EDOT-co-Py)/copper (II) oxide, (CuO) in the initial feed ratio of [EDOT]0/[Py]0 = 1/5 were electrosynthesized on glassy carbon electrode by cyclic voltammetric method. Their characterizations were performed by cyclic voltammetric, Fourier transform infrared-attenuated total reflectance, scanning electron microscopy, energy dispersion X-ray analysis, and electrochemical impedance spectroscopy. To the best of authors’ knowledge, the first report on polypyrrole/multi-walled carbon nanotube, PEDOT/multi-walled carbon nanotube, P(EDOT-co-Py)/multi-walled carbon nanotube and P(EDOT-co-Py)/CuO nanocomposite films were comparatively examined in 0.1 M NaClO4/CH3CN and in 0.1 M sodium dodecyl sulfate solutions. The highest specific capacitance for PEDOT/multi-walled carbon nanotube and polypyrrole/multi-walled carbon nanotube composite films were obtained as Csp = 306 mF × cm?2 for 3% multi-walled carbon nanotube and Csp = 804 mF × cm?2 for 1% multi-walled carbon nanotube, respectively. The highest specific capacitances were obtained as Csp = 27.40 mF × cm?2 and Csp = 26.90 mF × cm?2 for P(EDOT-co-Py)/multi-walled carbon nanotube includes the wt percent of 1% multi-walled carbon nanotube and P(EDOT-co-Py)/CuO includes the wt percent of 3% CuO, respectively. The Csp of P(EDOT-co-Py)/CNT composite films were calculated as 9.43 and 11.49 mF × cm?2 for 3 and 5% multi-walled carbon nanotube, respectively. In addition, The EIS results were simulated with the equivalent circuit model of Rs(Cdl1(R1(QR2)))(Cdl2R3).  相似文献   

4.
《Ceramics International》2019,45(11):14136-14145
Cupric oxide/reduced graphene oxide (CuO/rGO) nanocomposites were synthesized through a chemical reduction method using hydrazine hydrate as the reducing agent. The morphology, elemental composition, and bonding network of the CuO/rGOnanocomposites were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy respectively. The XRD results reveal lattice spacing and lattice strain from 3.371 to 3.428 Å and 1.05 × 10−3to 5.44 × 10−3 respectively, with the increasing ratio of rGO: CuO from 1:1 to 1:5. The cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS)and galvanostatic charge-discharge (GCD) studyofCuO/rGOas the electrode material showed excellent super-capacitive behavior in H2SO4 over Na2SO4 electrolytes. Moreover CuO/rGO nanocomposites exhibited better capacitance retention in H2SO4(75.69%) compared to Na2SO4(12.06%).  相似文献   

5.
A cauliflower-like ternary nanocomposite of poly(3,4-ethylenedioxythipohene)/nanocrystalline cellulose/manganese oxide (PEDOT/NCC/MnO2) was synthesized using one-step electropolymerization technique. The effect of manganese (Mn) concentration on the supercapacitive performance was investigated. The structural and morphology studies were conducted using field emission scanning electron microscope, Fourier transform infrared spectroscopy, Raman spectroscopy, and X-ray diffraction. The morphology of ternary nanocomposite at an optimized concentration of Mn resembles the cauliflower-like structure. The two-electrode electrochemical analysis of a ternary nanocomposite PEDOT/NCC/MnO2 exhibited a higher specific capacitance of 144.69 F/g at 25 mV/s in 1.0 M potassium chloride compared to PEDOT/NCC(63.57 F/g). PEDOT/NCC/MnO2 ternary nanocomposite was able to deliver a specific power of 494.9 W/kg and 10.3 Wh/kg of specific energy at 1 A g−1 and retained 83% of initial capacitance after 2,000 cycles. These promising results from the incorporation of Mn displayed great prospective in developing PEDOT/NCC/MnO2 as an electrode material for supercapacitor.  相似文献   

6.
In the present article, graphene oxide (GO) sheets and monoclinic copper oxide (CuO) nanocrystals are connected with each other and result in the formation of CuO/rGO nanopellets, and these nanopellets synthesized using coprecipitation method. The nanopellet structured CuO/rGO composite on carbon cloth, which act as current collector exhibits specific capacitance of 188 F g?1 at a current density of 0.2 A g?1 and up to 96.3% capacity retention after 2000 charge-discharge cycles. It shows a maximum energy density of 7.32 Wh kg?1 and power density of 53 W kg?1. The glucose sensing characteristics of CuO/rGO nanopellet is investigated on carbon cloth and ITO substrate. It shows glucose sensitivity of 0.805 mA mM?1 cm?2 and 0.2982 mA mM?1 cm?2 for a bundle like structured CuO/rGO composite on carbon cloth and ITO substrate, respectively. Further H2O2 sensing is studied on ITO substrate, which manifests H2O2 sensitivity of 84.39 μA mM?1 cm?2. The results indicate that nanopellet structured CuO/rGO composite could be a promising electrode material for supercapacitor, glucose, and H2O2 sensor.  相似文献   

7.
An ionic liquid (IL) supported composite of poly(3,4-ethylene dioxythiophene) (PEDOT) and graphene oxide (GO) is presented. GO was dispersed in ILs and electropolymerization carried out after loading of EDOT to the dried dispersion. The content of GO was optimized to obtain high electrical conductivity of the composite material. The IL acts as the dispersant for GO and as dopant in the synthesis of PEDOT leading to films with a highly porous structure indicated from the scanning electron microscopy (SEM) images. Subsequently, GO was reduced electrochemically by cyclic voltammetry to obtain PEDOT/rGO composite films. The successful formation of composite materials was confirmed using Raman and X-ray photoelectron spectroscopy (XPS) techniques. XPS was also used to verify removal of oxygen-containing functional groups upon electrochemical reduction of the composite films. The electrochemical properties of PEDOT, PEDOT/GO and PEDOT/rGO were studied using cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The results show that electrochemical reduction clearly increases the capacitance of the composite and furthermore the cycling stability. Such an increase could be obtained if >20 cycles, extending to highly negative potentials (−2.0 V), was used during the electroreduction of incorporated GO. Owing to the high porosity, favorable electrochemical properties and cycling stability these hybrid materials shows great potential towards supercapacitor applications.  相似文献   

8.
We present a facile one-step electrochemical approach to generate MnO2/rGO nanocomposite from a mixture of Mn3O4 and graphene oxide (GO). The electrochemical conversion of Mn3O4 into MnO2 through potential cycling is expedited in the presence of GO while the GO is reduced into reduced graphene oxide (rGO). The MnO2 nanoparticles are evenly distributed on the rGO nanosheets and act as the spacer to prevent rGO nanosheets from restacking. This unique structure provides high electroactive surface area (1173?m2 g?1) that improves ions diffusion within the MnO2/rGO structure. As a result, the MnO2/rGO nanocomposite exhibits high specific capacitance of 473?F?g?1 at 0.25?A?g?1, which is remarkably higher (3 times) than the Mn3O4/GO prior conversion. In addition, the electrosynthesized nanocomposite shows higher conductivity and excellent potential cycling stability of 95% at 2000 cycles.  相似文献   

9.
Sodium-substituted LiMnPO4/C/reduced graphene oxide (LNMP@rGO) was synthesized in this study via freeze drying and carbon thermal reduction method with graphene oxide as carbon source. Sodium ion doping is optimized and rGO effects are evaluated by XRD, SEM, TEM, BET, Raman, and electrochemical performance measurements. Well-distributed nanoparticles with average size of ~50?nm are evenly distributed on the surface or intercalation between rGO layers, resulting in a porous ion/electronic conductive network. Compared to 122.3?mA?h?g?1 in unmodified LNMP, the best LNMP@rGO (20?mg rGO) exhibits an excellent initial discharge capacity of 150.4?mA?h?g?1 at 0.05?C at 122.9% of the initial capacity. The capacity retention rate is 95.8% of the initial capacity after 100 cycles at 1?C. Capacity of 101.2?mA?h?g?1 is preserved even at rates as high as 10?C.  相似文献   

10.
Although supercapacitors have higher power density than batteries, they are still limited by low energy density and low capacity retention. Here we report a high-performance supercapacitor electrode of manganese oxide/reduced graphene oxide nanocomposite coated on flexible carbon fiber paper (MnO2–rGO/CFP). MnO2–rGO nanocomposite was produced using a colloidal mixing of rGO nanosheets and 1.8 ± 0.2 nm MnO2 nanoparticles. MnO2–rGO nanocomposite was coated on CFP using a spray-coating technique. MnO2–rGO/CFP exhibited ultrahigh specific capacitance and stability. The specific capacitance of MnO2–rGO/CFP determined by a galvanostatic charge–discharge method at 0.1 A g−1 is about 393 F g−1, which is 1.6-, 2.2-, 2.5-, and 7.4-fold higher than those of MnO2–GO/CFP, MnO2/CFP, rGO/CFP, and GO/CFP, respectively. The capacity retention of MnO2–rGO/CFP is over 98.5% of the original capacitance after 2000 cycles. This electrode has comparatively 6%, 11%, 13%, and 18% higher stability than MnO2–GO/CFP, MnO2/CFP, rGO/CFP, and GO/CFP, respectively. It is believed that the ultrahigh performance of MnO2–rGO/CFP is possibly due to high conductivity of rGO, high active surface area of tiny MnO2, and high porosity between each MnO2–rGO nanosheet coated on porous CFP. An as-fabricated all-solid-state prototype MnO2–rGO/CFP supercapacitor (2 × 14 cm) can spin up a 3 V motor for about 6 min.  相似文献   

11.
Four kinds of counter electrodes are prepared with polystyrene‐sulfonate doped poly(3,4‐ethylenedioxythiophene) (PEDOT‐PSS) as basic material, reduced graphene oxide (rGO) sheets as additives and H2SO4 as treating agent. The cyclic voltammetry and Tafel polarization are measured to evaluate catalytic activity of these counter electrodes for /I? redox couple. It is found that H2SO4 treated rGO and PEDOT‐PSS hybrid counter electrode (S/rGO/PEDOT‐PSS counter electrode) has the highest catalytic activity among these counter electrodes. Power conversion efficiency of the dye‐sensitized solar cell with S/rGO/PEDOT‐PSS counter electrode can attain to 7.065%, distinctly higher than that of the cells with the other three ones, owing to the great enhanced fill factor and short‐circuit current density. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42648.  相似文献   

12.
Reduced graphene oxide-poly(3,4-ethylenedioxythiophene):p-toluene sulfonate (rGO-PEDOT:PTS) hybrid electrode films were synthesized directly on a substrate by interfacial polymerization between an oxidizing solid layer and liquid droplets of 3,4-ethylenedioxythiophene (EDOT) produced by electrospraying. The EDOT reduced the graphene oxide by donating electrons during its transformation into PEDOT:PTS, and hybrid films consisting of rGO distributed in a matrix of PEDOT:PTS were obtained. These rGO-PEDOT:PTS hybrid films showed excellent electrical conductivities as high as 1,500 S/cm and a sheet resistance of 70 Ω sq-1. The conductivity values are up to 50% greater than those of films containing conductive PEDOT:PTS alone. These results confirm that highly conductive rGO-PEDOT:PTS hybrid films can potentially be used as organic transparent electrodes.  相似文献   

13.
Graphene platelets were synthesized from pencil flake graphite and commercial graphite by chemical method. The chemical method involved modified Hummer's method to synthesize graphene oxide (GO) and the use of hydrazine monohydrate to reduce GO to reduced graphene oxide (rGO). rGO were further reduced using rapid microwave treatment in presence of little amount of hydrazine monohydrate to graphene platelets. Chemically modified graphene/polypyrrole (PPy) nanofiber composites were prepared by in situ anodic electropolymerization of pyrrole monomer in the presence of graphene on stainless steel substrate. The morphology, composition, and electronic structure of the composites together with PPy fibers, graphene oxide (GO), rGO, and graphene were characterized using X‐ray diffraction (XRD), laser‐Raman, and scanning electron microscopic (SEM) methods. From SEM, it was observed that chemically modified graphene formed as a uniform nanocomposite with the PPy fibers absorbed on the graphene surface and/or filled between the graphene sheets. Such uniform structure together with the observed high conductivities afforded high specific capacitance and good cycling stability during the charge–discharge process when used as supercapacitor electrodes. A specific capacitance of supercapacitor was as high as 304 F g?1 at a current density of 2 mA cm?1 was achieved over a PPy‐doped graphene composite. POLYM. ENG. SCI., 55:2118–2126, 2015. © 2014 Society of Plastics Engineers  相似文献   

14.
In the present research work, [82Cu4Si14Zn]100-x – x wt% B4C (x?=?0, 3, 6, 9, and 12) nanocomposite powders had synthesized by mechanical alloying (MA). The MA process had carried out in a single vial high-energy planetary ball mill with the ball-to-powder ratio of 10:1 for 20?h. The results had revealed that the addition of B4C nano-ceramic particles had contributed more reduction on Cu-Zn-Si matrix powder particle size, changes in shapes, and structural refinement. The synthesized nanocomposite powders had characterized by advanced microscopes. The calculated average nanocomposite powder particle size was 13?±?1.2?µm, 9?±?0.8?µm, 5?±?0.65?µm, 3?±?0.4?µm, and 1?±?0.25?µm for 0, 3, 6, 9, and 12?wt% B4C reinforced nanocomposite powders respectively. Further, an average nanocrystallite size of 84?nm had obtained for [CuSi4Zn14]-0% B4C sample whereas 13?nm had achieved for [CuSi4Zn14]-12% B4C sample. This had attributed by variation in repeated cold welding, severe plastic deformation, and fragmentation of mechanical collisions with the function of boron carbide (B4C) nano-ceramic particles in Cu-Zn-Si matrix. In addition, the laser powder particle size (diameter, μm) and its distribution at D100, D10, D5, D1, D0.1, and D0.01 with the function of the percentage of B4C ceramic particles had also studied and investigated.  相似文献   

15.
The electron-donating substituted indole is generally difficult to be polymerized into high-quality film. The electrochemical polymerization of the electron-donating 3,4-ethylenedioxythiophene (EDOT)-monosubstituted indole may be a challenge. Herein, we designed and synthesized a novel fluorescent comonomer based on the combination of indole and EDOT groups, namely, 5-(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-1H-indole (EDTI), and subsequently electrodeposited into flawless freestanding flexible poly(5-(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-1H-indole) (PEDTI) film with a resistance of 60 MΩ/cm in CH2Cl2 containing 0.1 M Bu4NBF4. Electrochemical results showed that the oxidation onset potential of EDTI was at 0.8 V vs Ag/AgCl, which was lower than those of indole (0.96 V vs Ag/AgCl) and EDOT (1.35 V vs Ag/AgCl). FTIR spectra indicated that the polymerization of EDTI occurred at the 5-position on thiophene ring and 2,3-positions on indole ring, forming the crosslinking polymer film. The colors of as-prepared PEDTI could switch reversibly from purple to brown under applied potentials of 1.3 and −1.3 V, which were distinctly different from those of polyindole, poly(3,4-ethylenedioxythiophene) (PEDOT), and poly(EDOT-bis-substituted indole) (PETI). Fluorescence spectral studies revealed that the comonomer and corresponding polymer were good blue-green light emitters. These results implied that PEDTI had potential applications for photoelectric devices such as electrochromic devices, light-emitting diodes, and fluorescence sensors. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47016.  相似文献   

16.
We report polymer solar cells (PSCs) based on poly(3‐hexylthiophene (P3HT) and [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM) using water‐soluble nickel acetate (Ni(CH3COO)2, NiAc) instead of acidic poly(3,4‐ethylenedioxythiophene) : poly(styrenesulfonate) (PEDOT : PSS) as hole collection layer (HCL) between the indium tin oxide (ITO) electrode and photoactive layer. The NiAc layer can effectively decrease Rs and increase Rp and shows effective hole collection property. Under the illumination of AM1.5G, 100 mW/cm2, the short‐circuit current density (Jsc) of the NiAc based device (ITO/NiAc/P3HT : PCBM/Ca/Al) reach 11.36 mA/cm2, which is increased by 11% in comparison with that (10.19 mA/cm2) of PEDOT : PSS based device (ITO/PEDOT : PSS/P3HT : PCBM/Ca/Al). The power conversion efficiency of the NiAc based devices reach 3.76%, which is comparable to that (3.77%) of the device with PEDOT : PSS HCL under the same experimental conditions. Moreover, NiAc based PSCs show superior long‐term stability than PEDOT : PSS based PSCs. Our work gives a new option for HCL selection in designing more stable PSCs. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

17.
《Ceramics International》2016,42(11):13128-13135
A facile and well-controllable reduced graphene oxide/tungsten trioxide (rGO/WO3) nanocomposite electrode was successfully synthesized via an electrostatic assembly route at 350 rpm for 24 h. In this study, hexagonal-phase WO3 (h-WO3) nanofiber was well distributed on rGO sheets by applying optimal processing parameters. The as-synthesized rGO/WO3 nanocomposite electrode was compared with pure h-WO3 electrode. A maximum specific capacitance of 85.7 F g−1 at a current density of 0.7 A g−1 was obtained for the rGO/WO3 nanocomposite electrode, which showed better electrochemical performance than the WO3 electrode. The incorporation of WO3 into rGO could prevent the restacking of rGO and provide favourable surface adsorption sites for intercalation/de-intercalation reactions. The impedance studies demonstrated that the rGO/WO3 nanocomposite electrode exhibited lower resistance because of the superior conductivity of rGO that improved ion diffusion into the electrode. To evaluate the contribution of WO3 to the rGO/WO3 nanocomposite, the influence of mass loading of WO3 on the capacitance was investigated.  相似文献   

18.
Nafion-117/PEDOT composite membranes were synthesized by in situ chemical polymerization of 3,4-ethylenedioxythiophene (EDOT) using ammonium persulfate as an oxidant. The polymerization of EDOT in Nafion membranes for various EDOT/oxidant treatment sequences was studied for the first time. PEDOT introduction leads to a slight decrease in both the ion-exchange capacity and water uptake of the composite membranes, as well as to an increase in cationic transport. Membranes initially treated with an oxidant exhibit better conductivity and lower hydrogen permeability. The effect of both modification of Nafion-117 membranes by PEDOT and hot-pressing of hydrogen-oxygen membrane-electrode assemblies (MEAs) on the performance of proton-exchange membrane fuel cells was studied. The maximum power density of the fabricated MEAs increases 1.5-fold: from 510 (for a pristine Nafion-117 membrane) to 810 mW cm−2 (for a membrane modified by PEDOT). The current density at a voltage of 0.4 V reaches 1248 and 2246 mA cm−2, respectively.  相似文献   

19.
A symmetrical (p/p) supercapacitor has been fabricated by making use of activated carbon (AC)‐polyethylenedioxythiophene (PEDOT)‐composite electrodes for the first time. The composite electrodes have been prepared via electrochemical deposition of β‐napthalenesulphonate doped PEDOT onto AC electrodes. The characteristics of the electrodes and the fabricated supercapacitor have been investigated using cyclic voltammetry (CV) and AC impedance spectroscopy. The electrodes show a maximum specific capacitance of 158 Fg?1 at a scan rate of 10 mV s?1. This indicates that the in situ electro‐polymerization of ethylenedioxythiophene (EDOT) onto AC could improve the performance of carbon electrodes for use in supercapacitors. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008  相似文献   

20.
Poly(4‐(((2,3‐dihydrothieno[3,4‐b][1,4]dioxin‐2‐yl)methoxy)methyl)benzoic acid) (PEDOT‐Ph‐COOH) was facilely synthesized by the direct electropolymerization of 4‐(((2,3‐dihydrothieno[3,4‐b][1,4]dioxin‐2‐yl)methoxy)methyl)benzoic acid (EDOT‐Ph‐COOH) in CH2Cl2‐Bu4NPF6 (0.10 M) system, and the PEDOT‐Ph‐COOH films were systematically investigated. The results displayed that the film had excellent reversible redox activities, good electrochemical performance, and rough and compact surface. Finally, the PEDOT‐Ph‐COOH film was used as an optical chemo‐sensor for the highly selective and sensitive detection of F?, , , , Cu2+, and Fe3+ in dimethyl sulfoxide. Satisfactory results indicated that optical chemo‐sensor based on PEDOT‐Ph‐COOH possessed an excellent sensing performance and enhanced optical response, and it might be as potential promising materials, such as electrochromic devices, supercapacitors and so on. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41559.  相似文献   

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