scholarly journals High Specific Capacitance of the Electrodeposited MnO2 on Porous Foam Nickel Soaked in Alcohol and its Dependence on Precursor Concentration

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 181 ◽  
Author(s):  
Ming Zhang ◽  
Xiaoli Dai ◽  
Cuixian Zhang ◽  
Yuanwu Fuan ◽  
Dingyu Yang ◽  
...  

In this work, we used the mixed solution of manganese acetate and sodium sulfate to deposit manganese dioxide on the three-dimensional porous nickel foam that was previously soaked in alcohol, and then the effects of solution concentrations on their capacitance properties were investigated. The surface morphology, microstructure, elemental valence and other information of the material were observed by scanning electron microscope (SEM), Transmission Electron Microscope (TEM), X-ray photoelectron spectroscopy (XPS), etc. The electrochemical properties of the material were tested by Galvanostatic charge-discharge (GCD), Cyclic Voltammetry (CV), Chronoamperometry (CA), Electrochemical impedance spectroscopy (EIS), etc. The MnO2 electrode prepared at lower concentrations can respectively reach a specific capacitance of 529.5 F g−1 and 237.3 F g−1 at the current density of 1 A g−1 and 10 A g−1, and after 2000 cycles, the capacity retention rate was still 79.8% of the initial capacitance, and the energy density can even reach 59.4 Wh Kg−1, while at the same time, it also has a lower electrochemical impedance (Rs = 1.18 Ω, Rct = 0.84 Ω).

NANO ◽  
2018 ◽  
Vol 13 (01) ◽  
pp. 1850013 ◽  
Author(s):  
Chuanyin Xiong ◽  
Tiehu Li ◽  
Tingkai Zhao ◽  
Alei Dang ◽  
Xianglin Ji ◽  
...  

In this paper, a facile method is designed to fabricate three-dimensional (3D) graphene (GR)/manganese dioxide (MnO2) nanowall electrode material. The 3D GR/MnO2 hybrid is prepared by a combination of electrochemical deposition (ELD) and electrophoresis deposition (EPD), followed by thermal reduction (TR). Firstly, the 3D graphene oxide (GO)/MnO2 hybrid is obtained by the ELD–EPD method. Secondly, the 3D GR/MnO2 hybrid is obtained through hydrogen reduction at a certain temperature. The as-fabricated hybrid has been characterized by scanning electron microscope (SEM), transmission electron microscope (TEM) and Raman spectroscopy. The electrochemical properties have been also measured by cyclic voltammetry. The results showed that the 3D GR/MnO2 nanowalls hybrid has a high specific capacitance of 266.75[Formula: see text]Fg[Formula: see text] and a high energy density of 25.36[Formula: see text]Whkg[Formula: see text]. Moreover, a high specific capacitance (240.15[Formula: see text]Fg[Formula: see text]) at a high scan rate of 200[Formula: see text]mVs[Formula: see text] (90% capacity retention) has been also obtained. Additionally, the hybrid can serve directly as the electrodes of supercapacitor without adding binder. This work provides a novel road to fabricate a binder-free 3D GR-based hybrid for high-performance energy storage devices.


2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Yanfang Li ◽  
Zhenyin Hai ◽  
Xiaojuan Hou ◽  
Hongyan Xu ◽  
Zengxing Zhang ◽  
...  

Three-dimensional (3D) fennel-like cobalt oxide (II, III) (Co3O4) particles with thirty-six surfaces on nickel foams were prepared via a simple hydrothermal synthesis method and its growth process was also researched. The crystalline structure and morphology were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Raman spectroscopy. The Brunauer-Emmett-Teller (BET) analysis revealed that 3D fennel-like Co3O4 particles have high specific surface area. Therefore, the special structure with thirty-six surfaces indicates the good electrochemical performance of the micron-nanometer material as electrode material for supercapacitors. The cyclic voltammetry (CV), galvanostatic charge-discharge, and electrochemical impedance spectroscopy (EIS) were conducted to evaluate the electrochemical performances. Compared with other morphological materials of the similar sizes, the Co3O4 particles on nickel foam exhibit a high specific capacitance of 384.375 F·g−1 at the current density of 3 A·g−1 and excellent cycling stability of a capacitance retention of 96.54% after 1500 galvanostatic charge-discharge cycles in 6 M potassium hydroxide (KOH) electrolyte.


Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1143 ◽  
Author(s):  
Anil Yedluri ◽  
Tarugu Anitha ◽  
Hee-Je Kim

Hierarchical NiMoO4/NiMoO4 nanoflowers were fabricated on highly conductive flexible nickel foam (NF) substrates using a facile hydrothermal method to achieve rapid charge-discharge ability, high energy density, long cycling lifespan, and higher flexibility for high-performance supercapacitor electrode materials. The synthesized composite electrode material, NF/NiMoO4/NiMoO4 with a nanoball-like NF/NiMoO4 structure on a NiMoO4 surface over a NF substrate, formed a three-dimensional interconnected porous network for high-performance electrodes. The novel NF/NiMoO4/NiMoO4 nanoflowers not only enhanced the large surface area and increased the electrochemical activity, but also provided an enhanced rapid ion diffusion path and reduced the charge transfer resistance of the entire electrode effectively. The NF/NiMoO4/NiMoO4 composite exhibited significantly improved supercapacitor performance in terms of a sustained cycling life, high specific capacitance, rapid charge-discharge capability, high energy density, and good rate capability. Electrochemical analysis of the NF/NiMoO4/NiMoO4 nanoflowers fabricated on the NF substrate revealed ultra-high electrochemical performance with a high specific capacitance of 2121 F g−1 at 12 mA g−1 in a 3 M KOH electrolyte and 98.7% capacitance retention after 3000 cycles at 14 mA g−1. This performance was superior to the NF/NiMoO4 nanoball electrode (1672 F g−1 at 12 mA g−1 and capacitance retention 93.4% cycles). Most importantly, the SC (NF/NiMoO4/NiMoO4) device displayed a maximum energy density of 47.13 W h kg−1, which was significantly higher than that of NF/NiMoO4 (37.1 W h kg−1). Overall, the NF/NiMoO4/NiMoO4 composite is a suitable material for supercapacitor applications.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Xin Chen ◽  
Rui Xie ◽  
Hui Li ◽  
F. Jaber ◽  
F. Musharavati ◽  
...  

Abstract In this work, nickel cobaltite (NiCo2O4) nanosheets with a porous structure were fabricated on nickel foam as a working electrode for supercapacitor applications. The nanosheets were fabricated by electrochemical deposition of nickel–cobalt hydroxide on the nickel foam substrate at ambient temperature in a three-electrode cell followed by annealing at 300 °C to transform the coating into a porous NiCo2O4 nanosheet. Field emission scanning electron microscopy and transmission electron microscopy revealed a three-dimensional mesoporous structure, which facilitates ion transport and electronic conduction for fast redox reactions. For one cycle, the NiCo2O4 electrodeposited nickel foam has a high specific capacitance (1734.9 F g−1) at a current density (CD) of 2 A g−1. The electrode capacitance decreased by only approximately 12.7% after 3500 cycles at a CD of 30 A g−1. Moreover, a solid-state asymmetric supercapacitor (ASC) was built utilising the NiCo2O4 nanosheets, carbon nanotubes, and a polyvinyl alcohol-potassium hydroxide gel as the anode, cathode, and solid-state electrolyte, respectively. The ASC displayed great electrochemical properties with a 42.25 W h kg−1 energy density at a power density of 298.79 W kg−1.


RSC Advances ◽  
2016 ◽  
Vol 6 (64) ◽  
pp. 58994-59000 ◽  
Author(s):  
Abdul Muqsit Khattak ◽  
Huajie Yin ◽  
Zahid Ali Ghazi ◽  
Bin Liang ◽  
Azhar Iqbal ◽  
...  

Three dimensional iron oxide/graphene aerogel hybrid (Fe2O3/GA) was synthesized and used as electrode materials in flexible supercapacitor devices, which show high specific capacitance of 440 F g−1 with 89% capacitance retention after 2200 cycles.


Crystals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 356
Author(s):  
Kasimayan Uma ◽  
Elavarasan Muniranthinam ◽  
Siewhui Chong ◽  
Thomas C.-K Yang ◽  
Ja-Hon Lin

This report presents the synthesis of ZnO nanorod/α-Fe2O3 composites by the hydrothermal method with different weight percentages of α-Fe2O3 nanoparticles. The as-synthesized nanorod composites were characterized by different techniques, such as X-ray diffraction (XRD), Fourier transform-infrared (FT-IR), field emission scanning electron microscopy (FE-SEM), electrochemical impedance spectroscopy (EIS), and X-ray photoelectron spectroscopy (XPS). From our results, it was found that the ZnO/α-Fe2O3 (3 wt%) nanorod composites exhibit a higher hydrogen evolution reaction (HER) activity when compared to other composites. The synergetic effect between ZnO and (3 wt%) of α-Fe2O3 nanocomposites resulted in a low onset potential of −125 mV, which can effectively produce more H2 than pure ZnO. The H2 production rate over the composite of ZnO/α-Fe2O3 (3 wt%) clearly shows a significant improvement in the photocatalytic activity in the heterojunction of the ZnO nanorods and α-Fe2O3 nanoparticles on nickel foam.


2020 ◽  
Vol 13 (02) ◽  
pp. 2051005 ◽  
Author(s):  
Godlaveeti Sreenivasa Kumar ◽  
Somala Adinarayana Reddy ◽  
Hussen Maseed ◽  
Nagireddy Ramamanohar Reddy

In this work, we present the synthesis of a ternary CeO2–SnO2/rGO nanocomposite by using a facile one-step hydrothermal method. The as-synthesized composite was structural, chemical, morphological, elemental information studied by using different characterization techniques X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and field emission scanning electron microscope (FESEM), energy dispersive X-ray spectroscopy (EDAX) and transmission electron microscope (TEM). The CeO2–SnO2/rGO exhibited an excellent specific capacitance of 156[Formula: see text]F[Formula: see text][Formula: see text] at 0.5[Formula: see text]A/g in the presence of 3 M KOH solution. The synergic effect of CeO2, SnO2 and graphene composite coated on Ni foam endowed a high specific capacitance than their individual compounds. This work suggests that the novel ternary composite is a promising candidate for the high performance electrochemical energy storage and conversion systems.


2020 ◽  
Vol 12 (5) ◽  
pp. 693-700 ◽  
Author(s):  
Hao Cheng ◽  
Zhengyuan Zhou ◽  
Danfeng Qin ◽  
Wenyi Huang ◽  
Jun Feng ◽  
...  

In this study, a three-dimensional carbon nanofiber network was formed by first electrospinning a mixed solution of montmorillonite (MMT) and polyacrylonitrile (PAN), and then carbonizing the composite nanofiber and etching it with hydrofluoric acid. The form and morphology of the nanofibers were analysized by scanning electron microscopy (SEM), Raman microspectroscopy (Raman), and X-ray photoelectron spectroscopy (XPS). The sensor fabricated on three-dimensional carbon nanofiber showed a good linear response (y = 0.076x – 0.110, R2 = 0.999, and y = 0.193x – 1.770, R2 = 0.998), high stability and selectivity, and a low detection limit (0.4 μg · L–1) for Cu(II) as measured using differential pulse voltammetry under the optimal conditions, and the method mentioned above was also used to analyze Cu(II) in real tap water samples, which had good recoveries.


RSC Advances ◽  
2016 ◽  
Vol 6 (105) ◽  
pp. 102961-102967 ◽  
Author(s):  
Chandu V. V. M. Gopi ◽  
Mallineni Venkata-Haritha ◽  
Soo-Kyoung Kim ◽  
Kandasamy Prabakar ◽  
Hee-Je Kim

The flower-like ZnO@MnCo2O4 nanosheet electrode exhibited high specific capacitance than dandelion-like MnCo2O4.


2009 ◽  
Vol 60-61 ◽  
pp. 375-379
Author(s):  
Wei Sun ◽  
Hai Sheng San ◽  
Ying Xian Duo ◽  
Xu Yuan Chen

A novel electrode of supercapacitor was developed with a three dimensional (3D) structure which results in a significant increase of the electrode area per unit capacitor volume. An area of 2.58 times the area of corresponding planar design was obtained. The process flow for fabricating the 3D electrode was developed compatible with microelectromechanical system technology. The key processes were high-aspect-ratio Deep Reactive Ion Etching, electroless plating and electropolymerization. Ni as the current collector was deposited on Si/SiO2 substrate by using electroless plating, Polypyrrole was galvanostatically polymerized as electroactive film. The capacitance properties of the 3D electrode were investigated. Cyclic voltammetry tests show that the specific capacitance of the 3D electrode at 100 mV/s was 0.014 F/cm2 which is comparable with the 0.013 F/cm2 for the planar design. Electrochemical impedance spectroscopy plot of the 3D electrode is well fitted by equivalent circuit, we found the specific capacitance is 0.011 F/cm2 which is slightly larger than 0.0094 F/cm2 for similarly planar design. From the gavanostatic charge/discharge tests, the specific capacitance of the 3D electrode at 2 mA/cm2 is 0.011 F/cm2 while for planar design the corresponding value is 0.010 F/cm2. The results indicate the continuous and homogeneous Polypyrrole film with 3D structure was obtained as we designed.


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