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Mass production of highly-porous graphene for high-performance supercapacitors

View Article: PubMed Central - PubMed

ABSTRACT

This study reports on a facile and economical method for the scalable synthesis of few-layered graphene sheets by the microwave-assisted functionalization. Herein, single-layered and few-layered graphene sheets were produced by dispersion and exfoliation of functionalized graphite in ethylene glycol. Thermal treatment was used to prepare pure graphene without functional groups, and the pure graphene was labeled as thermally-treated graphene (T-GR). The morphological and statistical studies about the distribution of the number of layers showed that more than 90% of the flakes of T-GR had less than two layers and about 84% of T-GR were single-layered. The microwave-assisted exfoliation approach presents us with a possibility for a mass production of graphene at low cost and great potentials in energy storage applications of graphene-based materials. Owing to unique surface chemistry, the T-GR demonstrates an excellent energy storage performance, and the electrochemical capacitance is much higher than that of the other carbon-based nanostructures. The nanoscopic porous morphology of the T-GR-based electrodes made a significant contribution in increasing the BET surface as well as the specific capacitance of graphene. T-GR, with a capacitance of 354.1 Fg−1 at 5 mVs−1 and 264 Fg−1 at 100 mVs−1, exhibits excellent performance as a supercapacitor.

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(a–h) High-resolution TEM images of CE-GR (a–c) and T-GR (d–g) graphene. (h,i) Electron diffraction patterns taken from the positions of the red (h) and white spots (i), respectively, of the sheet shown in (d) with the peaks labelled by Miller–Bravais indices. The graphene is clearly one layer thick in (h) and two layers thick in (i). (j,k) Diffracted intensity taken along the 1–210 to –2110 axis for the patterns shown in (h,i) respectively. (l) Histogram of the ratios of the intensity of the {1100} and {2110} diffraction peaks for all the diffraction patterns collected.
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f4: (a–h) High-resolution TEM images of CE-GR (a–c) and T-GR (d–g) graphene. (h,i) Electron diffraction patterns taken from the positions of the red (h) and white spots (i), respectively, of the sheet shown in (d) with the peaks labelled by Miller–Bravais indices. The graphene is clearly one layer thick in (h) and two layers thick in (i). (j,k) Diffracted intensity taken along the 1–210 to –2110 axis for the patterns shown in (h,i) respectively. (l) Histogram of the ratios of the intensity of the {1100} and {2110} diffraction peaks for all the diffraction patterns collected.

Mentions: Figure 4 shows the transmission electron microscopy (TEM) images and select area electron diffraction (SAED) patterns of CE-GR and T-GR. Figure 4a–c show the TEM images of CE-GR, which included some individual graphene sheets with wrinkled morphology and folded edges. It can be seen that large graphene nanosheets (a few hundred square nanometers) resemble crumpled silk veil waves. Figure 4 (panels d–g) illustrate TEM images of the T-GR sample, which comprised of a single/few-layered graphene with large grain sizes. In addition, some of the small and big holes are obvious in Figure S6.


Mass production of highly-porous graphene for high-performance supercapacitors
(a–h) High-resolution TEM images of CE-GR (a–c) and T-GR (d–g) graphene. (h,i) Electron diffraction patterns taken from the positions of the red (h) and white spots (i), respectively, of the sheet shown in (d) with the peaks labelled by Miller–Bravais indices. The graphene is clearly one layer thick in (h) and two layers thick in (i). (j,k) Diffracted intensity taken along the 1–210 to –2110 axis for the patterns shown in (h,i) respectively. (l) Histogram of the ratios of the intensity of the {1100} and {2110} diffraction peaks for all the diffraction patterns collected.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5015014&req=5

f4: (a–h) High-resolution TEM images of CE-GR (a–c) and T-GR (d–g) graphene. (h,i) Electron diffraction patterns taken from the positions of the red (h) and white spots (i), respectively, of the sheet shown in (d) with the peaks labelled by Miller–Bravais indices. The graphene is clearly one layer thick in (h) and two layers thick in (i). (j,k) Diffracted intensity taken along the 1–210 to –2110 axis for the patterns shown in (h,i) respectively. (l) Histogram of the ratios of the intensity of the {1100} and {2110} diffraction peaks for all the diffraction patterns collected.
Mentions: Figure 4 shows the transmission electron microscopy (TEM) images and select area electron diffraction (SAED) patterns of CE-GR and T-GR. Figure 4a–c show the TEM images of CE-GR, which included some individual graphene sheets with wrinkled morphology and folded edges. It can be seen that large graphene nanosheets (a few hundred square nanometers) resemble crumpled silk veil waves. Figure 4 (panels d–g) illustrate TEM images of the T-GR sample, which comprised of a single/few-layered graphene with large grain sizes. In addition, some of the small and big holes are obvious in Figure S6.

View Article: PubMed Central - PubMed

ABSTRACT

This study reports on a facile and economical method for the scalable synthesis of few-layered graphene sheets by the microwave-assisted functionalization. Herein, single-layered and few-layered graphene sheets were produced by dispersion and exfoliation of functionalized graphite in ethylene glycol. Thermal treatment was used to prepare pure graphene without functional groups, and the pure graphene was labeled as thermally-treated graphene (T-GR). The morphological and statistical studies about the distribution of the number of layers showed that more than 90% of the flakes of T-GR had less than two layers and about 84% of T-GR were single-layered. The microwave-assisted exfoliation approach presents us with a possibility for a mass production of graphene at low cost and great potentials in energy storage applications of graphene-based materials. Owing to unique surface chemistry, the T-GR demonstrates an excellent energy storage performance, and the electrochemical capacitance is much higher than that of the other carbon-based nanostructures. The nanoscopic porous morphology of the T-GR-based electrodes made a significant contribution in increasing the BET surface as well as the specific capacitance of graphene. T-GR, with a capacitance of 354.1 Fg−1 at 5 mVs−1 and 264 Fg−1 at 100 mVs−1, exhibits excellent performance as a supercapacitor.

No MeSH data available.


Related in: MedlinePlus