Microwave-assisted reduction of graphene oxide for an electrochemical supercapacitor: Structural and capacitance behavior

Rosli, Nurul Hazwani Aminuddin; Lau, Kam Sheng; Winie, Tan; Chin, Siew Xian; Chia, Chin Hua

doi:10.1016/j.matchemphys.2021.124274

Cited by 18 publications

(7 citation statements)

References 68 publications

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“…The diffraction peaks of CoTe (PDF #34-0420) at 31.34°, 42.98°, 46.88°, and 58.26° were found in the spectra of all samples, thereby confirming the formation of CoTe. The diffraction peak of rGO could be observed at approximately 23°, and no GO diffraction peak was noted at 2θ = 10.9°; these results indicate that GO was completely reduced to rGO during the preparation of the electrode materials [27,28]. The magnified diffraction intensities of peaks over the 2θ range of 21°-28° are displayed to the right of Fig.…”

Section: Micromorphological and Structural Characterization Of Cote@rgomentioning

confidence: 79%

One-Step Hydrothermal Synthesis of a CoTe@rGO Electrode Material for Supercapacitors

Wang

Xiao

et al. 2021

Trans. Tianjin Univ.

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CoTe@reduced graphene oxide (CoTe@rGO) electrode materials for supercapacitors were prepared by a one-step hydrothermal method in this paper. Compared with that of pure CoTe, the electrochemical performance of CoTe@rGO was significantly improved. The results showed that the optimal CoTe@rGO electrode material has a remarkably high specific capacitance of 810.6 F/g at a current density of 1 A/g. At 5 A/g, the synthesized material retained 77.2% of its initial capacitance even after 5000 charge/discharge cycles, thereby demonstrating good cycling stability. Moreover, even at a high current density of 20 A/g, the composite electrode retained 79.0% of its specific capacitance at 1 A/g, thus confirming its excellent rate performance. An asymmetric supercapacitor (ASC) with a wider potential window and higher energy density was assembled by using 3 M KOH as the electrolyte, the CoTe@rGO electrode as the positive electrode, and active carbon as the negative electrode. The operating voltage of the supercapacitor could be increased to 1.6 V, and its specific capacitance could reach 112.6 F/g at 1 A/g. The specific capacitance retention rate of the fabricated supercapacitor after 5000 charge/discharge cycles at 5 A/g was 87.1%, which confirms its excellent cycling stability. In addition, the ASC revealed a high energy density of 40.04 W·h/kg at a power density of 799.91 W/kg and a high power density of 4004.93 W/kg at an energy density of 33.43 W·h/kg. These results collectively show that CoTe@rGO materials have broad application prospects.

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Section: Micromorphological and Structural Characterization Of Cote@rgomentioning

confidence: 79%

One-Step Hydrothermal Synthesis of a CoTe@rGO Electrode Material for Supercapacitors

Wang

Xiao

et al. 2021

Trans. Tianjin Univ.

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“…However, this trend reverts because the high reactivity of GrOP allows the consumption of a greater number of functional groups that generate more species that are gaseous. The increase in I D / I G of the nanohybrids with respect to GrOs reveals their thermal reduction and the removal of oxygen groups, generating a larger population of defects on the surface of both nanohybrids 46 . However, this reduction is less than that achieved in other microwave‐assisted processes ( I D / I G of 0.39 to 0.062) 37 due to GrOs are in a reactive medium, where their hybridization is promoted rather than their reduction 20,35 …”

Section: Resultsmentioning

confidence: 98%

Study of the dielectric heating of graphite oxide and its effect on the microwave‐assisted synthesis of Nylon‐6/graphite oxide polymeric hybrid nanocomposites

Ledezma-Rodríguez

Hernández

Yáñez‐Macías

et al. 2021

J of Applied Polymer Sci

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The present research focuses on the study of the microwave dielectric heating (DH) of graphite oxide (GrO) during the synthesis of Nylon-6/GrO hybrid polymeric nanocomposites (HPNCs) employing different microwave input powers and two GrO morphologies. In this regard, we evaluated GrO powder (GrOP) with dimensions ranging from nanometers to microns and GrO films (GrOF) with millimeter lengths and micron thicknesses. Both morphologies show the same oxidation degree and concentration of functional groups. However, they differ in the number of stacked graphene oxide sheets, thus modify their surface area. The results indicated that the morphology of GrO plays a determining role in its DH behavior in the microwave-assisted polymerization (MAP).On one hand, GrOF contains a high concentration of graphene sheets that induce both an increase in DH and the formation of hot spots. In addition, GrOF has a greater attractive force between its sheets, since its interlamellar space is smaller than 8.4 Å, which makes its exfoliation more difficult. The aforementioned effects significantly reduce the exfoliation and hybridization of GrOF. On the other hand, the larger interlamellar spacing in GrOP weakens the attractive forces compared to GrOF. The lower concentration of graphene oxide lamellae prevents the formation of hot spots, and homogeneously dissipates DH in the reaction medium, maximizing its exfoliation and hybridization. In addition, its behavior presents a defined trend concerning time. These results highlight the importance of considering the GrO morphology in the synthesis of HPNCs as it globally affects the MAPs process, as well as GrO reduction, exfoliation, and hybridization.

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“…The authors calculated in‐plane crystallite size ( La ) of the graphitic planes for the pronounced I D /I G ratios as shown (Figure 2) such as 0.98 < 1.03 > 1.01 using the relation () 48,49

italicLa goodbreak= \frac{4 \cdot 35}{I_{D} ∕ I_{G}} .

…”

Section: Resultsmentioning

confidence: 99%

Role of dual redox additivesKI/VOSO₄in manganese ammonium phosphate at graphene quantum dots for supercapattery

Raja

Vickraman

2022

Intl J of Energy Research

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The hybrid electrodes MnAP@GQD x are synthesized through microwave route for four graphene quantum dots (GQD) variates (x = 25, 50, 75, and 100 mg). The Debye-Scherrer calculations show lower crystallite size for MnAP at 75 mg GQD. In Raman studies, among all GQD variates the 75 mg GQD doped MnAP composite reveal higher I D /I G ratio (1.03). The electrochemical performance shows higher specific capacitance 596 Fg À1 at 1 Ag À1 for it. Thus, XRD, Raman, and CV studies identified 75 mg GQD as the appropriate mass dispersoid for MnAP lattice. This optimized MnAP at 75 mg GQD has been subjected to scanning electron microscopy (SEM), transmission electron microscopy (TEM), brunauer-emmet-teller (BET), and X-ray Photoelectron Spectroscopy (XPS). The SEM shows broken rectangular micro platelets for MnAP, and its disintegration after doping GQD x¼75 mg shows strong complexation. The BET study reveals mesoporosity (3 nm) favoring for better ionic transport, and the XPS accounts for the oxidation states. In full-cell, MnAP@GQD x¼75 mg as a positrode // rGO negatrode, has shown 442 Fg À1 at 1 Ag À1 in 3M H 2 SO 4 at 0-1.8 V. Further enhancement 693 Fg À1 in it, is achieved by dispersing dual redox additives 0.025M (KI/VOSO 4 ) in 3M H 2 SO 4 with 311 Wh kg À1 /450 W kg À1 at 1 Ag À1 and having the capacity retention 82% for 5000 cycles at 20 Ag À1 . Thus, increase in specific capacitance for this optimized electrode is observed for dual redox additives in 3M H 2 SO 4 suggestive for high-performance supercapattery applications.

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Microwave-assisted reduction of graphene oxide for an electrochemical supercapacitor: Structural and capacitance behavior

Cited by 18 publications

References 68 publications

One-Step Hydrothermal Synthesis of a CoTe@rGO Electrode Material for Supercapacitors

One-Step Hydrothermal Synthesis of a CoTe@rGO Electrode Material for Supercapacitors

Study of the dielectric heating of graphite oxide and its effect on the microwave‐assisted synthesis of Nylon‐6/graphite oxide polymeric hybrid nanocomposites

Role of dual redox additivesKI/VOSO₄in manganese ammonium phosphate at graphene quantum dots for supercapattery

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Microwave-assisted reduction of graphene oxide for an electrochemical supercapacitor: Structural and capacitance behavior

Cited by 18 publications

References 68 publications

One-Step Hydrothermal Synthesis of a CoTe@rGO Electrode Material for Supercapacitors

One-Step Hydrothermal Synthesis of a CoTe@rGO Electrode Material for Supercapacitors

Study of the dielectric heating of graphite oxide and its effect on the microwave‐assisted synthesis of Nylon‐6/graphite oxide polymeric hybrid nanocomposites

Role of dual redox additivesKI/VOSO4in manganese ammonium phosphate at graphene quantum dots for supercapattery

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Role of dual redox additivesKI/VOSO₄in manganese ammonium phosphate at graphene quantum dots for supercapattery