scholarly journals Graphene Oxide Decorated Nanometal-Poly(Anilino-Dodecylbenzene Sulfonic Acid) for Application in High Performance Supercapacitors

Micromachines ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 115 ◽  
Author(s):  
Nomxolisi R. Dywili ◽  
Afroditi Ntziouni ◽  
Chinwe Ikpo ◽  
Miranda Ndipingwi ◽  
Ntuthuko W. Hlongwa ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
High Resolution ◽  
Specific Capacitance ◽  
Sulfonic Acid ◽  
High Performance ◽  
Pt Nanoparticles ◽  
Metal Nanoparticle ◽  
Vibration Band ◽  
Dodecylbenzene Sulfonic Acid

Graphene oxide (GO) decorated with silver (Ag), copper (Cu) or platinum (Pt) nanoparticles that are anchored on dodecylbenzene sulfonic acid (DBSA)-doped polyaniline (PANI) were prepared by a simple one-step method and applied as novel materials for high performance supercapacitors. High-resolution transmission electron microscopy (HRTEM) and high-resolution scanning electron microscopy (HRSEM) analyses revealed that a metal-decorated polymer matrix is embedded within the GO sheet. This caused the M/DBSA–PANI (M = Ag, Cu or Pt) particles to adsorb on the surface of the GO sheets, appearing as aggregated dark regions in the HRSEM images. The Fourier transform infrared (FTIR) spectroscopy studies revealed that GO was successfully produced and decorated with Ag, Cu or Pt nanoparticles anchored on DBSA–PANI. This was confirmed by the appearance of the GO signature epoxy C–O vibration band at 1040 cm−1 (which decreased upon the introduction of metal nanoparticle) and the PANI characteristic N–H stretching vibration band at 3144 cm−1 present only in the GO/M/DBSA–PANI systems. The composites were tested for their suitability as supercapacitor materials; and specific capacitance values of 206.4, 192.8 and 227.2 F·g−1 were determined for GO/Ag/DBSA–PANI, GO/Cu/DBSA–PANI and GO/Pt/DBSA–PANI, respectively. The GO/Pt/DBSA–PANI electrode exhibited the best specific capacitance value of the three electrodes and also had twice the specific capacitance value reported for Graphene/MnO2//ACN (113.5 F·g−1). This makes GO/Pt/DBSA–PANI a very promising organic supercapacitor material.

Nitrogen-Enriched Reduced Graphene Oxide for High Performance Supercapacitor Electrode

2020 ◽  
Vol 20 (8) ◽  
pp. 4854-4859 ◽  
Author(s):  
Lei Chen ◽  
Xu Chen ◽  
Yaqiong Wen ◽  
Bixia Wang ◽  
Yangchen Wu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Specific Capacitance ◽  
Reduced Graphene Oxide ◽  
Electrode Material ◽  
High Performance ◽  
Electrode Materials ◽  
Electrochemical Impedance ◽  
Oxide Electrode ◽  
Reduced Graphene

Nitrogen-enriched reduced graphene oxide electrode material can be successfully prepared through a simple hydrothermal method. The morphology and microstructure of ready to use electrode material is measured by field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). Physical characterizations revealed that nitrogen-enriched reduced graphene oxide electrode material possessed high specific surface area of 429.6 m2 · g−1, resulting in high utilization of electrode materials with electrolyte. Electrochemical performance of nitrogen-enriched reduced graphene oxide electrode was also investigated by cyclic voltammetry (CV), galvanostatic charge/discharge measurements and electrochemical impedance spectroscopy (EIS) in aqueous in 6 M KOH with a three-electrode system, which displayed a high specific capacitance about 223.5 F · g−1 at 1 mV · s−1. More importantly, nitrogenenriched reduced graphene oxide electrode exhibited outstanding stability with 100% coulombic efficiency and with no specific capacitance loss under 2 A · g−1 after 10000 cycles. The supercapacitive behaviors indicated that nitrogen-enriched reduced graphene oxide can be a used as a promising electrode for high-performance super-capacitors.

scholarly journals Tuning the hierarchical pore structure of graphene oxide through dual thermal activation for high-performance supercapacitor

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jeongpil Kim ◽  
Jeong-Hyun Eum ◽  
Junhyeok Kang ◽  
Ohchan Kwon ◽  
Hansung Kim ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Pore Structure ◽  
Specific Capacitance ◽  
Surface Area ◽  
Thermal Annealing ◽  
High Performance ◽  
Annealing Process ◽  
Supercapacitor Electrode ◽  
Simple Method ◽  
Surface Areas

AbstractHerein, we introduce a simple method to prepare hierarchical graphene with a tunable pore structure by activating graphene oxide (GO) with a two-step thermal annealing process. First, GO was treated at 600 °C by rapid thermal annealing in air, followed by subsequent thermal annealing in N2. The prepared graphene powder comprised abundant slit nanopores and micropores, showing a large specific surface area of 653.2 m2/g with a microporous surface area of 367.2 m2/g under optimized conditions. The pore structure was easily tunable by controlling the oxidation degree of GO and by the second annealing process. When the graphene powder was used as the supercapacitor electrode, a specific capacitance of 372.1 F/g was achieved at 0.5 A/g in 1 M H2SO4 electrolyte, which is a significantly enhanced value compared to that obtained using activated carbon and commercial reduced GO. The performance of the supercapacitor was highly stable, showing 103.8% retention of specific capacitance after 10,000 cycles at 10 A/g. The influence of pore structure on the supercapacitor performance was systematically investigated by varying the ratio of micro- and external surface areas of graphene.

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.

Facile Synthesis of Modified MnO2/Reduced Graphene Oxide Nanocomposites and their Application in Supercapacitors

NANO ◽  
2020 ◽  
Vol 15 (08) ◽  
pp. 2050099
Author(s):  
Lijun Chen ◽  
Hongfeng Yin ◽  
Yuchao Zhang ◽  
Huidong Xie
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Specific Capacitance ◽  
Reduced Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Electrode Materials ◽  
Normal Pressure ◽  
X Ray ◽  
Assembly Method ◽  
Reduced Graphene

Herein, KH-550 was used as surface modifier to prepare modified MnO2/reduced graphene oxide (M-MnO2/rGO) composite electrode materials by utilizing electrostatic interaction at low temperature and normal pressure. X-ray diffraction, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy were adopted to characterize the material’s phase, morphology, and valence state of elements. The electrochemical properties of the material were measured using a three-electrode system. The results indicate a decrease in the size of the modified MnO2 particles, and that they were uniformly distributed on the rGO sheets. The M-MnO2/rGO composite attained a specific capacitance of 326[Formula: see text]F[Formula: see text]g[Formula: see text] in a solution of 1[Formula: see text]mol[Formula: see text]L[Formula: see text] Na2SO4 at a current density of 0.5[Formula: see text]A[Formula: see text]g[Formula: see text]. The specific capacitance of the material was 92.4% after 1000 cycles. The electrostatic self-assembly method effectively solved the problem of reducing the cycling stability while improving the specific capacitance of the composite materials, and further improved the possibility of applying MnO2/rGO in the field of supercapacitors.

scholarly journals Amino and PEG-amino graphene oxide grids enrich and protect samples for high-resolution single particle cryo-electron microscopy

2020 ◽  
Vol 209 (2) ◽  
pp. 107437 ◽  
Author(s):  
Feng Wang ◽  
Zanlin Yu ◽  
Miguel Betegon ◽  
Melody G. Campbell ◽  
Tural Aksel ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
High Resolution ◽  
Single Particle ◽  
Cryo Electron Microscopy ◽  
Resolution Single

High resolution Scanning Electron Microscopy

1989 ◽  
Vol 47 ◽  
pp. 6-7
Author(s):  
David C. Joy
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Resolution ◽  
High Performance ◽  
Secondary Electron ◽  
Wide Energy Range ◽  
Wide Energy ◽  
Electron Microscopes ◽  
Electron Imaging ◽  
Scanning Electron

High resolution scanning electron microscopy is still a relatively new and unfamiliar concept because in the early days of the SEM it was expected, that secondary electron imaging would be limited to a resolution of between 5 and 10nm at best. Now, however, because of improvements in instrumentation and technique based on advances in the understanding of electron beam interactions with solids current SEMs can demonstrate spatial resolutions below 1nm, rivaling those obtained by transmission instruments.High performance scanning electron microscopes always incorporate two advanced items of instrumentation. Firstly they use field emission guns (FEGs). The high brightness, low energy spread, and small source size of the FEG makes it possible to produce an electron probe of sub-nanometer size which contains sufficient current for secondary electron imaging (i.e 10-12 amps or more) and which can maintain this performance over a wide energy range (3 to 30keV). Secondly, the new high performance instruments place the specimen within a high excitation, immersion, probe forming lens.

Nanocomposite Sheets Composed of Polyaniline Nanoparticles and Graphene Oxide as Electrode Materials for High-performance Supercapacitor

2018 ◽  
Vol 21 (2) ◽  
pp. 097-102
Author(s):  
Shuhua Pang ◽  
Weiliang Chen ◽  
Zhewei Yang ◽  
Zheng Liu ◽  
Xin Fan ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Specific Capacitance ◽  
High Performance ◽  
Electrode Materials ◽  
Monomer Concentration ◽  
High Specific Capacitance ◽  
Chemical Oxidation ◽  
Aniline Monomer ◽  
Chemical Oxidation Polymerization ◽  
Fast Ion

Composite materials based on the combination of graphene oxide and PANI are expected not only to improve the PANI conductivity, but also relieve graphene oxide aggregation via a synergistic effect. We report an easy synthesis of a polyaniline/graphene oxide (PGO) composite with a relatively high specific capacitance by chemical oxidation polymerization. As the employ of phytic acid and increasing aniline monomer concentration, more and more PANI nanoparticles deposited into the interval between GO layers. PGO3 composite exhibits the largest specific capacitance (349 F·g-1) and PGO4 composite follows (314 F·g-1), whereas PGO has a minimal specific capacitance (206 F·g-1). The enhanced capacitance originates from the high capacitance of more PANI nanoparticles and better configuration as well as higher surface area of PGO3 and PGO4 composites for fast ion transport. The as-prepared PGO3 sheets composite with improved electrochemical performance is a promising electrode material for supercapacitor.

Fabrication of Homogeneously Dispersed Nanoneedle Manganese Dioxide/Graphene Composite for High-Performance Electrode Use in Supercapacitor

2014 ◽  
Vol 894 ◽  
pp. 8-12
Author(s):  
Myeong Jin Kim ◽  
Ki Ho Kim ◽  
Myeong Yeol Yoo ◽  
Joo Heon Kim
Keyword(s):  
Graphene Oxide ◽  
Specific Capacitance ◽  
Functional Groups ◽  
High Performance ◽  
Reaction Order ◽  
Graphene Sheets ◽  
Fabrication Method ◽  
Reduction Procedure ◽  
Second Stage ◽  
Graphene Composite

Two types of graphene/MnO2 composites were synthesized by different reaction procedures. R-GO/MnO2 was synthesized as follows: first, nanoneedle MnO2 was formed on the GO sheets using various functional groups (GO/MnO2). In the second stage, GO/MnO2 was reduced to graphene/MnO2 (R-GO/MnO2) via the dipping method. rGO/MnO2 was synthesized using a different reaction order: first, graphene oxide was reduced to graphene and nanoneedle MnO2 was formed on graphene sheets. Characterization indicated that the nanoneedle MnO2 structures in the R-GO/MnO2 composite were homogeneously dispersed on graphene sheets, whereas MnO2 in the rGO/MnO2 composite formed aggregates due to absence of functional groups. The R-GO/MnO2 electrode exhibited a specific capacitance as high as 327.5 Fg-1at 10 mVs-1, which was higher than that of the rGO/MnO2 electrode (229.9 Fg-1). It is anticipated that the formation of nanoneedle MnO2 on the GO surface following the reduction procedure could be a promising fabrication method for supercapacitor electrodes.

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