scholarly journals Novel Thermally Reduced Graphene Oxide Microsupercapacitor Fabricated via Mask—Free AxiDraw Direct Writing

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1909
Author(s):  
Vusani M. Maphiri ◽  
Gift Rutavi ◽  
Ndeye F. Sylla ◽  
Saheed A. Adewinbi ◽  
Oladepo Fasakin ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Electrochemical Performance ◽  
Reduced Graphene Oxide ◽  
Functional Groups ◽  
Electrochemical Impedance ◽  
Chemical Vapor ◽  
Equivalent Series Resistance ◽  
Direct Writing ◽  
Simple Method ◽  
Reduced Graphene

We demonstrate a simple method to fabricate all solid state, thermally reduced Graphene Oxide (TRGO) microsupercapacitors (µ-SCs) prepared using the atmospheric pressure chemical vapor deposition (APCVD) and a mask-free axiDraw sketching apparatus. The Fourier transform infrared spectroscopy (FTIR) shows the extermination of oxygen functional groups as the reducing temperature (RT) increases, while the Raman shows the presence of the defect and graphitic peaks. The electrochemical performance of the µ-SCs showed cyclic voltammetry (CV) potential window of 0–0.8 V at various scan rates of 5–1000 mVs−1 with a rectangular shape, depicting characteristics of electric double layer capacitor (EDLC) behavior. The µ-SC with 14 cm−2 (number of digits per unit area) showed a 46% increment in capacitance from that of 6 cm−2, which is also higher than the µ-SCs with 22 and 26 cm−2. The TRGO-500 exhibits volumetric energy and power density of 14.61 mW h cm−3 and 142.67 mW cm−3, respectively. The electrochemical impedance spectroscopy (EIS) showed the decrease in the equivalent series resistance (ESR) as a function of RT due to reduction of the resistive functional groups present in the sample. Bode plot showed a phase angel of −85° for the TRGO-500 µ-SC device. The electrochemical performance of the µ-SC devices can be tuned by varying the RT, number of digits per unity area, and connection configuration (parallel or series).

scholarly journals A Facile and Green Synthesis of a MoO2-Reduced Graphene Oxide Aerogel for Energy Storage Devices

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 594 ◽  
Author(s):  
Mara Serrapede ◽  
Marco Fontana ◽  
Arnaud Gigot ◽  
Marco Armandi ◽  
Glenda Biasotto ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Chemical Reduction ◽  
Low Cost ◽  
Xps Analysis ◽  
3D Scaffold ◽  
Energy Storage Devices ◽  
Reduced Graphene

A simple, low cost, and “green” method of hydrothermal synthesis, based on the addition of l-ascorbic acid (l-AA) as a reducing agent, is presented in order to obtain reduced graphene oxide (rGO) and hybrid rGO-MoO2 aerogels for the fabrication of supercapacitors. The resulting high degree of chemical reduction of graphene oxide (GO), confirmed by X-Ray Photoelectron Spectroscopy (XPS) analysis, is shown to produce a better electrical double layer (EDL) capacitance, as shown by cyclic voltammetric (CV) measurements. Moreover, a good reduction yield of the carbonaceous 3D-scaffold seems to be achievable even when the precursor of molybdenum oxide is added to the pristine slurry in order to get the hybrid rGO-MoO2 compound. The pseudocapacitance contribution from the resulting embedded MoO2 microstructures, was then studied by means of CV and electrochemical impedance spectroscopy (EIS). The oxidation state of the molybdenum in the MoO2 particles embedded in the rGO aerogel was deeply studied by means of XPS analysis and valuable information on the electrochemical behavior, according to the involved redox reactions, was obtained. Finally, the increased stability of the aerogels prepared with l-AA, after charge-discharge cycling, was demonstrated and confirmed by means of Field Emission Scanning Electron Microscopy (FESEM) characterization.

scholarly journals Functionalized Reduced Graphene Oxide Thin Films for Ultrahigh CO2 Gas Sensing Performance at Room Temperature

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 623
Author(s):  
Monika Gupta ◽  
Huzein Fahmi Hawari ◽  
Pradeep Kumar ◽  
Zainal Arif Burhanudin ◽  
Nelson Tansu
Keyword(s):  
Thin Films ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Gas Sensor ◽  
Functional Groups ◽  
Recovery Time ◽  
Room Temperature ◽  
Co2 Gas ◽  
Reduced Graphene ◽  
Response And Recovery

The demand for carbon dioxide (CO2) gas detection is increasing nowadays. However, its fast detection at room temperature (RT) is a major challenge. Graphene is found to be the most promising sensing material for RT detection, owing to its high surface area and electrical conductivity. In this work, we report a highly edge functionalized chemically synthesized reduced graphene oxide (rGO) thin films to achieve fast sensing response for CO2 gas at room temperature. The high amount of edge functional groups is prominent for the sorption of CO2 molecules. Initially, rGO is synthesized by reduction of GO using ascorbic acid (AA) as a reducing agent. Three different concentrations of rGO are prepared using three AA concentrations (25, 50, and 100 mg) to optimize the material properties such as functional groups and conductivity. Thin films of three different AA reduced rGO suspensions (AArGO25, AArGO50, AArGO100) are developed and later analyzed using standard FTIR, XRD, Raman, XPS, TEM, SEM, and four-point probe measurement techniques. We find that the highest edge functionality is achieved by the AArGO25 sample with a conductivity of ~1389 S/cm. The functionalized AArGO25 gas sensor shows recordable high sensing properties (response and recovery time) with good repeatability for CO2 at room temperature at 500 ppm and 50 ppm. Short response and recovery time of ~26 s and ~10 s, respectively, are achieved for 500 ppm CO2 gas with the sensitivity of ~50 Hz/µg. We believe that a highly functionalized AArGO CO2 gas sensor could be applicable for enhanced oil recovery, industrial and domestic safety applications.

Two-dimensional hybrid nanosheets of few layered MoSe2 on reduced graphene oxide as anodes for long-cycle-life lithium-ion batteries

2016 ◽  
Vol 4 (40) ◽  
pp. 15302-15308 ◽  
Author(s):  
Zhigao Luo ◽  
Jiang Zhou ◽  
Lirong Wang ◽  
Guozhao Fang ◽  
Anqiang Pan ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Electrochemical Performance ◽  
Lithium Ion Batteries ◽  
Reduced Graphene Oxide ◽  
Lithium Ion ◽  
Cycle Life ◽  
Two Dimensional ◽  
Long Cycle Life ◽  
Excellent Electrochemical Performance ◽  
Reduced Graphene

We report the synthesis of a novel 2D hybrid nanosheet constructed by few layered MoSe2 grown on reduced graphene oxide (rGO), which exhibits excellent electrochemical performance as anodes for lithium ion batteries.

Synthesis of reduced graphene oxide by an ionothermal method and electrochemical performance

RSC Advances ◽  
2013 ◽  
Vol 3 (29) ◽  
pp. 11807 ◽  
Author(s):  
Changdong Gu ◽  
Heng Zhang ◽  
Xiuli Wang ◽  
Jiangping Tu
Keyword(s):  
Graphene Oxide ◽  
Electrochemical Performance ◽  
Reduced Graphene Oxide ◽  
Reduced Graphene

Electrochemical performance and transformation of Co-MOF/reduced graphene oxide composite

2017 ◽  
Vol 193 ◽  
pp. 216-219 ◽  
Author(s):  
Zifeng Wang ◽  
Chengwei Gao ◽  
Yushan Liu ◽  
Dan Li ◽  
Weihua Chen ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Electrochemical Performance ◽  
Reduced Graphene Oxide ◽  
Oxide Composite ◽  
Reduced Graphene

Unusual morphologies of reduced graphene oxide and polyaniline nanofibers-reduced graphene oxide composites for high performance supercapacitor applications

RSC Advances ◽  
2014 ◽  
Vol 4 (43) ◽  
pp. 22551-22560 ◽  
Author(s):  
Rahul S. Diggikar ◽  
Dattatray J. Late ◽  
Bharat B. Kale
Keyword(s):  
Graphene Oxide ◽  
Electrochemical Performance ◽  
Reduced Graphene Oxide ◽  
High Performance ◽  
Polyaniline Nanofibers ◽  
Pani Nanofibers ◽  
Reduced Graphene ◽  
Oxide Composites ◽  
Enhanced Electrochemical Performance ◽  
Supercapacitor Applications

The unique morphologies of reduced graphene oxide (RGO) and RGO–PANI nanofibers (NF) composites have been demonstrated. The enhanced electrochemical performance was observed for honeycomb like RGO–PANI NFs composites.

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