A FACILE ONE-STEP HYDROTHERMAL METHOD TO PRODUCE GRAPHENE OXIDE/Fe2O3-NANOTUBES COMPOSITES AND ITS ELECTROCHEMICAL PROPERTIES

NANO ◽  
2012 ◽  
Vol 07 (04) ◽  
pp. 1250032 ◽  
Author(s):  
WEN FU ◽  
CHUNNIAN CHEN
Keyword(s):  
Graphene Oxide ◽  
Electrochemical Properties ◽  
Specific Capacitance ◽  
Hydrothermal Method ◽  
High Specific Capacitance ◽  
Cyclic Voltammogram ◽  
Transmission Electron Microscopy Analysis ◽  
Electron Microscopy Analysis ◽  
One Step ◽  
Charge Discharge

The composites of graphene oxide/ Fe2O3-nanotubes (GO/ Fe2O3-NTs) have been fabricated through a facile one-step hydrothermal method. Fe2O3-NTs crystallines were homogeneously distributed on GO, which have been confirmed by transmission electron microscopy analysis (TEM). The structure, composition and electrochemical properties of GO/ Fe2O3-NTs composites were investigated by means of selective-area electron diffraction (SAED), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Raman spectra, cyclic voltammogram (CV) curves and galvanostatic charge–discharge curves. GO/ Fe2O3-NTs composites exhibit a high specific capacitance of 133.2 Fg-1in 1 M Li2SO4electrolyte. In addition, the GO/ Fe2O3-NTs composites electrode shows good long-term cycle stability (only 9% decrease of the specific capacitance is observed after 1000 charge–discharge cycles).

Structural and Electrochemical Study of Dandelion-Like Manganese Dioxide Synthesized by a New Microwave Hydrothermal Method

2011 ◽  
Vol 233-235 ◽  
pp. 1516-1519
Author(s):  
Jian Ling Li ◽  
Yi Tuo Wang ◽  
Ya Kun Zhang ◽  
Gui Mei Han ◽  
Fei Gao ◽  
...  
Keyword(s):  
Electrochemical Properties ◽  
Specific Capacitance ◽  
Hydrothermal Method ◽  
Electrochemical Impedance ◽  
Active Material ◽  
High Specific Capacitance ◽  
Microwave Hydrothermal ◽  
Microwave Hydrothermal Method ◽  
Novel Method ◽  
First Time

The microwave-hydrothermal method for synthesizing g-MnO2 has been investigated for the first time. The dandelion-like g-MnO2 active material with 1.0-5.0 μm in diameter was obtained from KBrO3 and MnSO4 via the novel method. Compared with traditional low-temperature hydrothermal method, this approach lowers the temperature by 30-40 °C, and shorts the reaction time 6-14 h. Electrochemical properties of dandelion-like γ-MnO2were elucidated by cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy tests. The synthesized material shows a relative high specific capacitance, and the MnO2 obtained at the condition of 75 °C for 2 h shows the best electrochemical properties with a specific capacitance of 239.3 F·g-1 at the current density of 100 mA·g-1 in 6 M KOH electrolyte solution.

Preparation and Electrochemical Properties of VO2(B) Nano-Belts

2011 ◽  
Vol 694 ◽  
pp. 91-97
Author(s):  
Yu Long Qiao ◽  
Yong Jun Ma ◽  
Qing Ping Luo ◽  
Chong Hua Pei
Keyword(s):  
Cyclic Voltammetry ◽  
Energy Loss ◽  
Electrochemical Properties ◽  
Specific Capacitance ◽  
Hydrothermal Method ◽  
Monoclinic Phase ◽  
Galvanostatic Charge ◽  
Crystal Direction ◽  
Electron Energy Loss ◽  
Charge Discharge

The VO2(B) nanobelts with monoclinic phase were synthesized by a hydrothermal method at 220°C for 48 h in the absence of any surfactants. The electron energy loss spectrum (EELS) demonstrates that vanadium exists only in the 4+ oxidation state. The SEM and TEM images reveal a belt-like structure of the VO2(B) with the length of several micrometers, the width of 140 nm and the thickness of around 20nm and growth along the [110] crystal direction. Cyclic voltammetry (CV) and galvanostatic charge/discharge demonstrate that VO2(B) nano-belts electrode exhibits desirable electrochemical properties and the specific capacitance reaches up to 632.6F•g-1.

Preparation and Electrochemical Properties of Graphene/MnO2 Nanocomposites for Supercapacitors

2018 ◽  
Vol 768 ◽  
pp. 102-108 ◽  
Author(s):  
Hai Bo Sun ◽  
Hua Zhi Gu ◽  
Yao Chen
Keyword(s):  
Graphene Oxide ◽  
Electrochemical Performance ◽  
Electrochemical Properties ◽  
Specific Capacitance ◽  
Hydrothermal Method ◽  
Raw Materials ◽  
Simple Hydrothermal Method ◽  
Neutral Electrolyte

In the present work, we demonstrated a facile process to prepare graphene/MnO2composites via a simple hydrothermal method at 120 °C using KMnO4and graphene oxide as raw materials followed by reduction with or without hydrazine. The electrochemical performance of the graphene/MnO2composites were investigated in a neutral electrolyte of Na2SO4. Among these samples, the sample rGM3prepared without hydrazine show uniform morphology and the best electrochemical performance. The specific capacitance of rGM3is 169 F g-1at a specific current of 0.2 A g-1. It exhibits a maintenance of 75.5 % of the initial capacitance after 1000 cycles. The results manifest that the graphene/MnO2composites can be potentially applied in supercapacitors.

scholarly journals Fabrication of Hierarchical NiMoO4/NiMoO4 Nanoflowers on Highly Conductive Flexible Nickel Foam Substrate as a Capacitive Electrode Material for Supercapacitors with Enhanced Electrochemical Performance

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1143 ◽  
Author(s):  
Anil Yedluri ◽  
Tarugu Anitha ◽  
Hee-Je Kim
Keyword(s):  
Energy Density ◽  
Electrochemical Performance ◽  
Specific Capacitance ◽  
Electrode Material ◽  
High Performance ◽  
Nickel Foam ◽  
High Specific Capacitance ◽  
High Energy ◽  
High Energy Density ◽  
Charge Discharge

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.

A novel synthesis of ultra thin graphene sheets for energy storage applications using malonic acid as a reducing agent

2014 ◽  
Vol 2 (47) ◽  
pp. 20345-20357 ◽  
Author(s):  
Anil Kumar ◽  
Mahima Khandelwal
Keyword(s):  
Energy Storage ◽  
Potential Energy ◽  
Specific Capacitance ◽  
Malonic Acid ◽  
High Specific Capacitance ◽  
Reducing Agent ◽  
Graphene Sheets ◽  
Novel Synthesis ◽  
Energy Storage Applications ◽  
Charge Discharge

Novel ultrathin graphene sheets (0.41 ± 0.03 nm) with increased sp2 character, high specific capacitance and charge–discharge capability have been synthesized and demonstrated to have potential energy storage applications.

scholarly journals Dissected carbon nanotubes functionalized by 1-hydroxyanthraquinone for high-performance asymmetric supercapacitors

RSC Advances ◽  
2017 ◽  
Vol 7 (76) ◽  
pp. 48341-48353 ◽  
Author(s):  
Xia Yang ◽  
Yuying Yang ◽  
Quancai Zhang ◽  
Xiaotong Wang ◽  
Yufeng An ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Graphene Oxide ◽  
Specific Capacitance ◽  
Reduced Graphene Oxide ◽  
High Performance ◽  
Rate Capability ◽  
High Specific Capacitance ◽  
Covalent Modification ◽  
Asymmetric Supercapacitors ◽  
Reduced Graphene

1-Hydroxyanthraquinone (HAQ) is selected to functionalize the dissected carbon nanotubes (rDCNTs) with reduced graphene oxide layers through non-covalent modification. The composite achieves high specific capacitance and ultrahigh rate capability.

Pseudocapacitance and excellent cyclability of 2,5-dimethoxy-1,4-benzoquinone on graphene

2016 ◽  
Vol 9 (8) ◽  
pp. 2586-2594 ◽  
Author(s):  
Muhammad Boota ◽  
Chi Chen ◽  
Matthieu Bécuwe ◽  
Ling Miao ◽  
Yury Gogotsi
Keyword(s):  
Graphene Oxide ◽  
Hydrothermal Method ◽  
Reduced Graphene Oxide ◽  
Three Dimensional ◽  
Covalent Functionalization ◽  
Redox Active ◽  
Reduced Graphene ◽  
One Step ◽  
Volumetric Capacitance ◽  
Graphene Oxide Sheets

Non-covalent functionalization of 2,5-dimethoxy-1,4-benzoquinone and hydroquinone on reduced graphene oxide sheets led to the formation of a redox-active three-dimensional gel architecture via a one-step hydrothermal method, where the former exhibited high gravimetric and volumetric capacitance and 99% capacitance retention after 25 000 cycles at 50 mV s−1.

Facile hydrothermal synthesis of ternary CeO2–SnO2/rGO nanocomposite for supercapacitor application

2020 ◽  
Vol 13 (02) ◽  
pp. 2051005 ◽  
Author(s):  
Godlaveeti Sreenivasa Kumar ◽  
Somala Adinarayana Reddy ◽  
Hussen Maseed ◽  
Nagireddy Ramamanohar Reddy
Keyword(s):  
Electron Microscope ◽  
Specific Capacitance ◽  
High Performance ◽  
High Specific Capacitance ◽  
Energy Storage And Conversion ◽  
X Ray Diffraction ◽  
X Ray ◽  
Supercapacitor Application ◽  
Transmission Electron ◽  
One Step

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.

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