scholarly journals Comparison of Laser-Synthetized Nanographene-Based Electrodes for Flexible Supercapacitors

Micromachines ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 555
Author(s):  
Francisco J. Romero ◽  
Denice Gerardo ◽  
Raul Romero ◽  
Inmaculada Ortiz-Gomez ◽  
Alfonso Salinas-Castillo ◽  
...  
Keyword(s):  
Specific Capacitance ◽  
Co2 Laser ◽  
High Performance ◽  
Low Cost ◽  
Cost Effective ◽  
Uv Laser ◽  
Infrared Wavelength ◽  
Flexible Supercapacitors ◽  
Cost Effective Method ◽  
Reduced Graphene

In this paper, we present a comparative study of a cost-effective method for the mass fabrication of electrodes to be used in thin-film flexible supercapacitors. This technique is based on the laser-synthesis of graphene-based nanomaterials, specifically, laser-induced graphene and reduced graphene oxide. The synthesis of these materials was performed using two different lasers: a CO2 laser with an infrared wavelength of λ = 10.6 µm and a UV laser (λ = 405 nm). After the optimization of the parameters of both lasers for this purpose, the performance of these materials as bare electrodes for flexible supercapacitors was studied in a comparative way. The experiments showed that the electrodes synthetized with the low-cost UV laser compete well in terms of specific capacitance with those obtained with the CO2 laser, while the best performance is provided by the rGO electrodes fabricated with the CO2 laser. It has also been demonstrated that the degree of reduction achieved with the UV laser for the rGO patterns was not enough to provide a good interaction electrode-electrolyte. Finally, we proved that the specific capacitance achieved with the presented supercapacitors can be improved by modifying the in-planar structure, without compromising their performance, which, together with their compatibility with doping-techniques and surface treatments processes, shows the potential of this technology for the fabrication of future high-performance and inexpensive flexible supercapacitors.

Combustion Synthesis of Graphene from Waste Paper for High Performance Supercapacitor Electrodes

2017 ◽  
Vol 17 (01n02) ◽  
pp. 1760023 ◽  
Author(s):  
Dayakar Chowdary Singu ◽  
B. Joseph ◽  
V. Velmurugan ◽  
Syamsai Ravuri ◽  
A. Nirmala Grace
Keyword(s):  
High Performance ◽  
Low Cost ◽  
Cost Effective ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electrochemical Supercapacitor ◽  
Cost Effective Method ◽  
Discharge Duration ◽  
Graphene Paper ◽  
Supercapacitor Applications

Incessant streak of unsuccessful attempts to synthesize low cost graphene with larger flake size and purity is frequently reported. Any reported methods that result in few layers of graphene with minimal contamination are definitive to exist. In this work, graphene was prepared economically from source of “paper” and detailed investigation was done on the effect of synthesizing parameters like paper source, temperature and amount of urea in the formation of graphene. This is a cost effective method, in which the paper that we use in our daily life was carbonized with the help of urea at a temperature of 850[Formula: see text]C under N2 atmosphere. The paper source was varied, shape of the paper was altered and the graphene paper with large surface area was synthesized without smudging and the prepared graphene paper was analyzed by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) for its structural, morphological investigation. To test the supercapacitance performance, electrochemical behavior was investigated in 6[Formula: see text]M KOH electrolyte. The specific capacitance of 1122[Formula: see text]F/g was obtained at 5[Formula: see text]mV/s scan rate. Chronopotentiometry curves showed an excellent cyclic stability with higher charge/discharge duration and hence could be used for electrochemical supercapacitor applications.

scholarly journals Plasma Surface Functionalization of Carbon Nanofibres with Silver, Palladium and Platinum Nanoparticles for Cost-Effective and High-Performance Supercapacitors

Micromachines ◽  
2018 ◽  
Vol 10 (1) ◽  
pp. 2 ◽  
Author(s):  
Zelun Li ◽  
Shaojun Qi ◽  
Yana Liang ◽  
Zhenxue Zhang ◽  
Xiaoying Li ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Specific Capacitance ◽  
Surface Area ◽  
High Performance ◽  
Electrochemical Impedance ◽  
Low Cost ◽  
Cost Effective ◽  
Carbon Nanofibres ◽  
X Ray ◽  
Active Screen

Due to their relatively low cost, large surface area and good chemical and physical properties, carbon nanofibers (CNFs) are attractive for the fabrication of electrodes for supercapacitors (SCs). However, their relatively low electrical conductivity has impeded their practical application. To this end, a novel active-screen plasma activation and deposition technology has been developed to deposit silver, platinum and palladium nanoparticles on activated CNFs surfaces to increase their specific surface area and electrical conductivity, thus improving the specific capacitance. The functionalised CNFs were fully characterised using scanning electron microscope (SEM), energy dispersive X-ray analysis (EDX) and X-ray diffraction (XRD) and their electrochemical properties were evaluated using cyclic voltammetry and electrochemical impedance spectroscopy. The results showed a significant improvement in specific capacitance, as well as electrochemical impedance over the untreated CNFs. The functionalisation of CNFs via environmental-friendly active-screen plasma technology provides a promising future for cost-effective supercapacitors with high power and energy density.

scholarly journals Soft and wrinkled carbon membranes derived from petals for flexible supercapacitors

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Xiuxiu Yu ◽  
Ying Wang ◽  
Li Li ◽  
Hongbian Li ◽  
Yuanyuan Shang
Keyword(s):  
Specific Capacitance ◽  
Electrode Material ◽  
Low Cost ◽  
Current Collector ◽  
High Specific Capacitance ◽  
Cost Effective ◽  
Cycling Performance ◽  
Carbon Membrane ◽  
Flower Petal ◽  
Flexible Supercapacitors

Abstract Biomass materials are promising precursors for the production of carbonaceous materials due to their abundance, low cost and renewability. Here, a freestanding wrinkled carbon membrane (WCM) electrode material for flexible supercapacitors (SCs) was obtained from flower petal. The carbon membrane was fabricated by a simple thermal pyrolysis process and further activated by heating the sample in air. As a binder and current collector-free electrode, the activated wrinkled carbon membrane (AWCM) exhibited a high specific capacitance of 332.7 F/g and excellent cycling performance with 92.3% capacitance retention over 10000 cycles. Moreover, a flexible all-solid supercapacitor with AWCM electrode was fabricated and showed a maximum specific capacitance of 154 F/g and great bending stability. The development of this flower petal based carbon membrane provides a promising cost-effective and environmental benign electrode material for flexible energy storage.

MnO2 Nanorods Embedded Reduced Graphene Oxide Nanocomposite with Ultrahigh Specific Capacitance and Excellent Cyclic Stability for High Performance Supercapacitors

2019 ◽  
Vol 07 (01n02) ◽  
pp. 1950005
Author(s):  
Muhammad Sajjad ◽  
Azhar Iqbal ◽  
Muhammad Ibrar Khan ◽  
Muhammad Tauseef Qureshi ◽  
Yaqoob Khan
Keyword(s):  
Specific Capacitance ◽  
Current Density ◽  
High Performance ◽  
Solution Process ◽  
High Specific Capacitance ◽  
Cost Effective ◽  
Cycling Stability ◽  
Reduced Graphene ◽  
Excellent Cycling Stability ◽  
Mg Content

Excellent cycling stability along with a high specific capacitance of the electrode material is the primary requirement for supercapacitor (SC) in recent years. Exceptionally simple and cost-effective solution process is employed for the first time to prepare [Formula: see text]-MnO2/rGO composites, in which KMnO4 content varies from (2[Formula: see text]mg, 4[Formula: see text]mg, 6[Formula: see text]mg and 8[Formula: see text]mg). The morphological analysis showed that [Formula: see text]-MnO2/rGO composites possess nanorod like morphology and were fully covered with rGO sheet. Among all composites, the sample with 6[Formula: see text]mg content of KMnO4 denoted as [Formula: see text]-MnO2/rGO composite (S–3) showed excellent supercapacitive performance with a specific capacitance of 720[Formula: see text]F/g at a current density of 4 A g[Formula: see text] with excellent cycling stability of 93% after 2000 cycles. Furthermore, these nanocomposites showed excellent supercapacitive properties with specific capacitances of 720–498 F/g at the current density of 4 A g[Formula: see text] with cycling stabilities of 71%, 68% and 60%, respectively.

Azo (Hydrazone) pigments: general principles

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Robert Christie
Keyword(s):  
High Performance ◽  
Metal Salt ◽  
Low Cost ◽  
Cost Effective ◽  
Precipitation Process ◽  
Ambient Temperatures ◽  
Technical Performance ◽  
Chemical Structures ◽  
General Chemical ◽  
Physical Form

Abstract This paper presents an overview of the general chemical principles underlying the structures, synthesis and technical performance of azo pigments, the dominant chemical class of industrial organic pigments in the yellow, orange, and red shade areas, both numerically and in terms of tonnage manufactured. A description of the most significant historical features in this group of pigments is provided, starting from the discovery of the chemistry on which azo colorants are based by Griess in the mid-nineteenth century, through the commercial introduction of the most important classical azo pigments in the early twentieth century, including products known as the Hansa Yellows, β-naphthol reds, including metal salt pigments, and the diarylide yellows and oranges, to the development in the 1950s and 1960s of two classes of azo pigments that exhibit high performance, disazo condensation pigments and benzimidazolone-based azo pigments. A feature that complicates the description of the chemical structures of azo pigments is that they exist in the solid state as the ketohydrazone rather than the hydroxyazo form, in which they have been traditionally been illustrated. Numerous structural studies conducted over the years on an extensive range of azo pigments have demonstrated this feature. In this text, they are referred to throughout as azo (hydrazone) pigments. Since a common synthetic procedure is used in the manufacture of virtually all azo (hydrazone) pigments, this is discussed in some detail, including practical aspects. The procedure brings together two organic components as the fundamental starting materials, a diazo component and a coupling component. An important reason for the dominance of azo (hydrazone) pigments is that they are highly cost-effective. The syntheses generally involve low cost, commodity organic starting materials and are carried out in water as the reaction solvent, which offers obvious economic and environmental advantages. The versatility of the approach means that an immense number of products may be prepared, so that they have been adapted structurally to meet the requirements of many applications. On an industrial scale, the processes are straightforward, making use of simple, multi-purpose chemical plant. Azo pigments may be produced in virtually quantitative yields and the processes are carried out at or below ambient temperatures, thus presenting low energy requirements. Finally, provided that careful control of the reaction conditions is maintained, azo pigments may be prepared directly by an aqueous precipitation process that can optimise physical form, with control of particle size distribution, crystalline structure, and surface character. The applications of azo pigments are outlined, with more detail reserved for subsequent papers on individual products.

Metal-organic framework derived metal oxide/reduced graphene oxide nanocomposite, a new tool for the determination of dipyridamole

2021 ◽  
Author(s):  
Naeime Salandari-Jolge ◽  
Ali A. Ensafi ◽  
Behzad Rezaei
Keyword(s):  
Myocardial Infarction ◽  
Graphene Oxide ◽  
High Performance ◽  
High Selectivity ◽  
Low Cost ◽  
Metal Organic Framework ◽  
Heart Patients ◽  
Reduced Graphene ◽  
Metal Organic

Dipyridamole is a prescribed medication used to treat cardiovascular diseases, angina pectoris, imaging tests for heart patients, and myocardial infarction. Therefore, high selectivity and sensitivity, low cost, and high-performance speed...

scholarly journals Rapid Detection and Quantification of Patulin and Citrinin Contamination in Fruits

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4545
Author(s):  
Sudharsan Sadhasivam ◽  
Omer Barda ◽  
Varda Zakin ◽  
Ram Reifen ◽  
Edward Sionov
Keyword(s):  
High Performance ◽  
Cost Effective ◽  
Hplc Method ◽  
Pear Fruit ◽  
Cost Effective Method ◽  
Fruit Samples ◽  
Pome Fruits ◽  
Reliable Methods ◽  
By Products ◽  
Detection And Quantification

Patulin (PAT) and citrinin (CTN) are the most common mycotoxins produced by Penicillium and Aspergillus species and are often associated with fruits and fruit by-products. Hence, simple and reliable methods for monitoring these toxins in foodstuffs are required for regular quality assessment. In this study, we aimed to establish a cost-effective method for detection and quantification of PAT and CTN in pome fruits, such as apples and pears, using high-performance liquid chromatography (HPLC) coupled with spectroscopic detectors without the need for any clean-up steps. The method showed good performance in the analysis of these mycotoxins in apple and pear fruit samples with recovery ranges of 55–97% for PAT and 84–101% for CTN, respectively. The limits of detection (LOD) of PAT and CTN in fruits were 0.006 µg/g and 0.001 µg/g, while their limits of quantification (LOQ) were 0.018 µg/g and 0.003 µg/g, respectively. The present findings indicate that the newly developed HPLC method provides rapid and accurate detection of PAT and CTN in fruits.

scholarly journals Simultaneously Regulating Uniform Zn2+ Flux and Electron Conduction by MOF/rGO Interlayers for High-Performance Zn Anodes

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Ziqi Wang ◽  
Liubing Dong ◽  
Weiyuan Huang ◽  
Hao Jia ◽  
Qinghe Zhao ◽  
...  
Keyword(s):  
High Performance ◽  
Surface Passivation ◽  
Coulombic Efficiency ◽  
Low Cost ◽  
Metal Organic Framework ◽  
Growth Surface ◽  
Electron Conduction ◽  
Reduced Graphene ◽  
Metal Organic ◽  
Further Development

AbstractOwing to the merits of low cost, high safety and environmental benignity, rechargeable aqueous Zn-based batteries (ZBs) have gained tremendous attention in recent years. Nevertheless, the poor reversibility of Zn anodes that originates from dendrite growth, surface passivation and corrosion, severely hinders the further development of ZBs. To tackle these issues, here we report a Janus separator based on a Zn-ion conductive metal–organic framework (MOF) and reduced graphene oxide (rGO), which is able to regulate uniform Zn2+ flux and electron conduction simultaneously during battery operation. Facilitated by the MOF/rGO bifunctional interlayers, the Zn anodes demonstrate stable plating/stripping behavior (over 500 h at 1 mA cm−2), high Coulombic efficiency (99.2% at 2 mA cm−2 after 100 cycles) and reduced redox barrier. Moreover, it is also found that the Zn corrosion can be effectively retarded through diminishing the potential discrepancy on Zn surface. Such a separator engineering also saliently promotes the overall performance of Zn|MnO2 full cells, which deliver nearly 100% capacity retention after 2000 cycles at 4 A g−1 and high power density over 10 kW kg−1. This work provides a feasible route to the high-performance Zn anodes for ZBs.

THEORETICAL ANALYSES FOR LASER MACHINING MICROCHANNELS AND DEMONSTRATION OF THEIR USES IN MANUFACTURE OF A MICROFLUIDIC OPTICAL SWITCH

2006 ◽  
Vol 13 (06) ◽  
pp. 795-802 ◽  
Author(s):  
DANIEL LIM ◽  
ERNA GONDO SANTOSO ◽  
KIM MING TEH ◽  
STEPHEN WAN ◽  
H. Y. ZHENG
Keyword(s):  
Fluid Flow ◽  
Optical Switch ◽  
Low Cost ◽  
Microfluidic Devices ◽  
Cost Effective ◽  
Laser Machining ◽  
Machining Parameters ◽  
Flow Channels ◽  
Cost Effective Method ◽  
Theoretical Analyses

Silicon has been widely used to fabricate microfluidic devices due to the dominance of silicon microfabrication technologies available. In this paper, theoretical analyses are carried out to suggest suitable laser machining parameters to achieve required channel geometries. Based on the analyses, a low-power CO 2 laser was employed to create microchannels in Acrylic substrate for the use of manufacturing an optical bubble switch. The developed equations are found useful for selecting appropriate machining parameters. The ability to use a low-cost CO 2 laser to fabricate microchannels provides an alternative and cost-effective method for prototyping fluid flow channels, chambers and cavities in microfluidic lab chips.

scholarly journals Synchronous fluorescence as a green and selective tool for simultaneous determination of bambuterol and its main degradation product, terbutaline

2018 ◽  
Vol 5 (10) ◽  
pp. 181359 ◽  
Author(s):  
Samah Abo El Abass ◽  
Heba Elmansi
Keyword(s):  
Degradation Product ◽  
Low Cost ◽  
Reference Method ◽  
Cost Effective ◽  
Zero Crossing ◽  
Cost Effective Method ◽  
Validation Parameters ◽  
Main Degradation Product ◽  
20 Nm

A green, sensitive and cost-effective method is introduced in this research for the determination of bambuterol and its main degradation product, terbutaline, simultaneously, relying on the synchronous spectrofluorimetric technique. First derivative synchronous spectrofluorimetric amplitude is measured at Δ λ = 20 nm, so bambuterol can be quantitated at 260 nm, and terbutaline can be measured at 290 nm, each at the zero crossing point of the other. The amplitude–concentration plots were linear over the concentration ranges of 0.2–6.0 µg ml −1 and 0.2–4.0 µg ml −1 for both bambuterol and terbutaline, respectively. Official guidelines were followed to calculate the validation parameters of the proposed method. The low values of limits of detection of 0.023, 0.056 µg ml −1 and limits of quantitation of 0.071, 0.169 µg ml −1 for bambuterol and terbutaline, respectively, point to the sensitivity of the method. Bambuterol is a prodrug for terbutaline, and the latter is considered its degradation product so the established method could be regarded as a stability-indicating one. Moreover, the proposed method was used for the analysis of bambuterol and terbutaline in their single ingredient preparations and the results revealed statistical agreement with the reference method. The suggested method, being a simple and low-cost procedure, is superior to the previously published methods which need more sophisticated techniques, longer analysis time and highly toxic solvents and reagents. It could be considered as an eco-friendly analytical procedure.

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