scholarly journals Metal-Free Carbon-Based Supercapacitors—A Comprehensive Review

Electrochem ◽  
2020 ◽  
Vol 1 (4) ◽  
pp. 410-438
Author(s):  
Noureen Siraj ◽  
Samantha Macchi ◽  
Brian Berry ◽  
Tito Viswanathan
Keyword(s):  
Specific Capacitance ◽  
Low Cost ◽  
Metal Free ◽  
Energy Applications ◽  
Carbon Compounds ◽  
Elemental Doping ◽  
Forms Of Carbon ◽  
Supercapacitor Applications ◽  
Carbon Based

Herein, metal-free heteroatom doped carbon-based materials are being reviewed for supercapacitor and energy applications. Most of these low-cost materials considered are also derived from renewable resources. Various forms of carbon that have been employed for supercapacitor applications are described in detail, and advantages as well as disadvantages of each form are presented. Different methodologies that are being used to develop these materials are also discussed. To increase the specific capacitance, carbon-based materials are often doped with different elements. The role of doping elements on the performance of supercapacitors has been critically reviewed. It has been demonstrated that a higher content of doping elements significantly improves the supercapacitor behavior of carbon compounds. In order to attain a high percentage of elemental doping, precursors with variable ratios as well as simple modifications in the syntheses scheme have been employed. Significance of carbon-based materials doped with one and more than one heteroatom have also been presented. In addition to doping elements, other factors which play a key role in enhancing the specific capacitance values such as surface area, morphology, pore size electrolyte, and presence of functional groups on the surface of carbon-based supercapacitor materials have also been summarized.

scholarly journals N-doped carbon nanomaterials are durable catalysts for oxygen reduction reaction in acidic fuel cells

2015 ◽  
Vol 1 (1) ◽  
pp. e1400129 ◽  
Author(s):  
Jianglan Shui ◽  
Min Wang ◽  
Feng Du ◽  
Liming Dai
Keyword(s):  
Fuel Cells ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Carbon Nanomaterials ◽  
Low Cost ◽  
Clean Energy ◽  
Pem Fuel Cells ◽  
Reduction Reaction ◽  
Metal Free ◽  
Carbon Based

The availability of low-cost, efficient, and durable catalysts for oxygen reduction reaction (ORR) is a prerequisite for commercialization of the fuel cell technology. Along with intensive research efforts of more than half a century in developing nonprecious metal catalysts (NPMCs) to replace the expensive and scarce platinum-based catalysts, a new class of carbon-based, low-cost, metal-free ORR catalysts was demonstrated to show superior ORR performance to commercial platinum catalysts, particularly in alkaline electrolytes. However, their large-scale practical application in more popular acidic polymer electrolyte membrane (PEM) fuel cells remained elusive because they are often found to be less effective in acidic electrolytes, and no attempt has been made for a single PEM cell test. We demonstrated that rationally designed, metal-free, nitrogen-doped carbon nanotubes and their graphene composites exhibited significantly better long-term operational stabilities and comparable gravimetric power densities with respect to the best NPMC in acidic PEM cells. This work represents a major breakthrough in removing the bottlenecks to translate low-cost, metal-free, carbon-based ORR catalysts to commercial reality, and opens avenues for clean energy generation from affordable and durable fuel cells.

N-doped porous carbon derived from walnut shells with enhanced electrochemical performance for supercapacitor

2019 ◽  
Vol 12 (03) ◽  
pp. 1950042 ◽  
Author(s):  
Yunfeng Wang ◽  
Honghui Jiang ◽  
Shewen Ye ◽  
Jiaming Zhou ◽  
Jiahao Chen ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Specific Capacitance ◽  
Porous Carbon ◽  
Low Cost ◽  
High Specific Capacitance ◽  
Cycling Stability ◽  
Electrochemical Performances ◽  
Walnut Shells ◽  
Electrochemical Cycling ◽  
Elemental Doping

As the low-cost, natural multi-component for elemental doping and environment-friendly characteristics, biomass-derived porous carbon for energy storage attracts intense attention. Herein, walnut shells-based porous carbon has been obtained through carbonization, hydrothermal and activation treatment. The corresponding porous carbon owns superior electrochemical performances with specific capacitance reaching up to 462[Formula: see text]F[Formula: see text]g[Formula: see text] at 1[Formula: see text]A[Formula: see text]g[Formula: see text], and shows excellent cycling stability (5000 cycles, [Formula: see text]94.2% of capacitance retention at 10[Formula: see text]A[Formula: see text]g[Formula: see text]). Moreover, the symmetry supercapacitor achieves high specific capacitance (197[Formula: see text]F[Formula: see text]g[Formula: see text] at 1[Formula: see text]A[Formula: see text]g[Formula: see text]), relevant electrochemical cycling stability (5000 cycles, 89.2% of capacitance retention at 5[Formula: see text]A[Formula: see text]g[Formula: see text]) and high power/energy density (42.8[Formula: see text]W[Formula: see text]h[Formula: see text]kg[Formula: see text] at 1249[Formula: see text]W[Formula: see text]kg[Formula: see text]). Therefore, the facile synthesis approach and superb electrochemical performance ensure that the walnut shells-derived porous carbon is a promising electrode material candidate for supercapacitors.

scholarly journals Carbon-Based Metal-Free Electrocatalysis for Energy Conversion, Energy Storage, and Environmental Protection

2018 ◽  
Vol 1 (1) ◽  
pp. 84-112 ◽  
Author(s):  
Chuangang Hu ◽  
Ying Xiao ◽  
Yuqin Zou ◽  
Liming Dai
Keyword(s):  
Energy Conversion ◽  
Environmental Protection ◽  
Low Cost ◽  
Clean Energy ◽  
Strong Stability ◽  
Structure Design ◽  
Device Fabrication ◽  
Environmental Friendliness ◽  
Metal Free ◽  
Carbon Based

Abstract Carbon-based metal-free catalysts possess desirable properties such as high earth abundance, low cost, high electrical conductivity, structural tunability, good selectivity, strong stability in acidic/alkaline conditions, and environmental friendliness. Because of these properties, these catalysts have recently received increasing attention in energy and environmental applications. Subsequently, various carbon-based electrocatalysts have been developed to replace noble metal catalysts for low-cost renewable generation and storage of clean energy and environmental protection through metal-free electrocatalysis. This article provides an up-to-date review of this rapidly developing field by critically assessing recent advances in the mechanistic understanding, structure design, and material/device fabrication of metal-free carbon-based electrocatalysts for clean energy conversion/storage and environmental protection, along with discussions on current challenges and perspectives. Graphical Abstract

Flexible Interdigital In-Plane Supercapacitor Based on Laser Reduced Graphene Oxide (LRGO)

2016 ◽  
Vol 705 ◽  
pp. 138-144 ◽  
Author(s):  
Engy Ghoniem ◽  
Ahmed A. El-Moneim
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Unit Area ◽  
Low Cost ◽  
Poly Vinyl Alcohol ◽  
Flexible Supercapacitor ◽  
Reduced Graphene ◽  
Conventional Structure ◽  
Supercapacitor Applications

We Demonstrated and Verified the Use Of laser Reduced Graphene Oxide (LRGO) Supported on Polyethylene Terephthalate (PET) Substrate for Flexible Supercapacitor Applications. we Compared the Interdigitated in-Plan Structure with the Conventionally Stacked Structure Supercapacitor. To understand the Role of Increasing the Number of Sub-Electrodes per Unit Area, Three electrode Architecture of 2, 4, and 6 Sub-Electrodes were Studied. Polymeric Gel electrolyte of Poly (vinyl Alcohol) and Phosphoric Acid (PVA-H3PO4)was Selected for the Realization of the Cells. the Interdigital in – Planesupercapacitor with 6 Sub-Electrodes I-PS(6) Showed a Volumetric Capacitance Of9.3 Fcm-3 Opposed to 3.6, 0.6, 0.5 Fcm-3 for I-PS(4), I-PS(2), and conventional Structure Supercapacitor, Respectively at 0.1 Ma Cm-2 Current Density. the Maximum Stated Energy Density of 0.409 Mwh.cm-3and Power Density of 994.6 W.cm-3 were for I-PS(6). our Results clearly Showed that the LRGO can Hold much Promise for Low-Cost, Easy, and Scalablesupercapacitor Fabrication.

scholarly journals Carbon nanomaterials for metal-free electrocatalysis

2020 ◽  
Vol 3 (1) ◽  
pp. 55
Author(s):  
Ana M.B. Honorato ◽  
Mohd Khalid
Keyword(s):  
Energy Conversion ◽  
Carbon Nanomaterials ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Metal Free ◽  
Hydrogen Evolution Reactions ◽  
Storage Technologies ◽  
Conversion Technologies ◽  
Carbon Based

Carbon materials are continuing in progress to accomplish the requirements of energy conversion and energy storage technologies because of their plenty in nature, high surface area, outstanding electrical properties, and readily obtained from varieties of chemical and natural sources. Recently, carbon-based electrocatalysts have been developed in the quest to replacement of noble metal based catalysts for low cost energy conversion technologies, such as fuel cell, water splitting, and metal-air batteries. Herein, we will present our short overview on recently developed carbon-based electrocatalysts for energy conversion reactions such as oxygen reduction, oxygen evolution, and hydrogen evolution reactions, along with challenges and perspectives in the emerging field of metal-free electrocatalysts.

scholarly journals The Role of Functionalization in the Applications of Carbon Materials: An Overview

2019 ◽  
Vol 5 (4) ◽  
pp. 84 ◽  
Author(s):  
Giorgio Speranza
Keyword(s):  
Surface Chemistry ◽  
Carbon Nanostructures ◽  
Chemical Properties ◽  
Covalent Bonds ◽  
Forms Of Carbon ◽  
Life On Earth ◽  
Physical And Chemical ◽  
Enormous Number ◽  
Carbon Based

The carbon-based materials (CbMs) refer to a class of substances in which the carbon atoms can assume different hybridization states (sp1, sp2, sp3) leading to different allotropic structures -. In these substances, the carbon atoms can form robust covalent bonds with other carbon atoms or with a vast class of metallic and non-metallic elements, giving rise to an enormous number of compounds from small molecules to long chains to solids. This is one of the reasons why the carbon chemistry is at the basis of the organic chemistry and the biochemistry from which life on earth was born. In this context, the surface chemistry assumes a substantial role dictating the physical and chemical properties of the carbon-based materials. Different functionalities are obtained by bonding carbon atoms with heteroatoms (mainly oxygen, nitrogen, sulfur) determining a certain reactivity of the compound which otherwise is rather weak. This holds for classic materials such as the diamond, the graphite, the carbon black and the porous carbon but functionalization is widely applied also to the carbon nanostructures which came at play mainly in the last two decades. As a matter of fact, nowadays, in addition to fabrication of nano and porous structures, the functionalization of CbMs is at the basis of a number of applications as catalysis, energy conversion, sensing, biomedicine, adsorption etc. This work is dedicated to the modification of the surface chemistry reviewing the different approaches also considering the different macro and nano allotropic forms of carbon.

The role of iodine in the enhancement of the supercapacitance properties of HI-treated flexible reduced graphene oxide film: an experimental study with insights from DFT simulations

2020 ◽  
Vol 44 (4) ◽  
pp. 1418-1425
Author(s):  
Swagatika Kamila ◽  
Manikandan Kandasamy ◽  
Brahmananda Chakraborty ◽  
Bikash Kumar Jena
Keyword(s):  
Experimental Study ◽  
Graphene Oxide ◽  
Oxide Film ◽  
Specific Capacitance ◽  
Reduced Graphene Oxide ◽  
Reduced Graphene ◽  
Dft Simulations ◽  
Supercapacitor Applications

Iodine on graphene frameworks enhances the specific capacitance towards supercapacitor applications.

Metal-free heteroatom-doped carbon-based catalysts for ORR: A critical assessment about the role of heteroatoms

Carbon ◽  
2020 ◽  
Vol 165 ◽  
pp. 434-454 ◽  
Author(s):  
Javier Quílez-Bermejo ◽  
Emilia Morallón ◽  
Diego Cazorla-Amorós
Keyword(s):  
Critical Assessment ◽  
Metal Free ◽  
Carbon Based

scholarly journals A Rapid Synthesis of Mesoporous Mn2O3 Nanoparticles for Supercapacitor Applications

Coatings ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 631 ◽  
Author(s):  
You-Hyun Son ◽  
Phuong T. M. Bui ◽  
Ha-Ryeon Lee ◽  
Mohammad Shaheer Akhtar ◽  
Deb Kumar Shah ◽  
...  
Keyword(s):  
Electrochemical Properties ◽  
Specific Capacitance ◽  
Active Sites ◽  
Low Cost ◽  
Hydrothermal Process ◽  
High Specific Capacitance ◽  
Manganese Acetate ◽  
Benign Nature ◽  
Supercapacitor Applications ◽  
Mn2o3 Nanoparticles

Mn2O3 nanomaterials have been recently composing a variety of electrochemical systems like fuel cells, supercapacitors, etc., due to their high specific capacitance, low cost, abundance and environmentally benign nature. In this work, mesoporous Mn2O3 nanoparticles (NPs) were synthesized by manganese acetate, citric acid and sodium hydroxide through a hydrothermal process at 150 °C for 3 h. The synthesized mesoporous Mn2O3 NPs were thoroughly characterized in terms of their morphology, surfaces, as well as their crystalline, electrochemical and electrochemical properties. For supercapacitor applications, the synthesized mesoporous Mn2O3 NP-based electrode accomplished an excellent specific capacitance (Csp) of 460 F·g−1 at 10 mV·s−1 with a good electrocatalytic activity by observing good electrochemical properties in a 6 M KOH electrolyte. The excellent Csp might be explained by the improvement of the surface area, porous surface and uniformity, which might favor the generation of large active sites and a fast ionic transport over the good electrocatalytic surface of the Mn2O3 electrode. The fabricated supercapacitors exhibited a good cycling stability after 5000 cycles by maintaining ~83% of Csp.

Understanding the Role of Chlorine and Ozone to Control Postharvest Diseases in Fruit and Vegetables: A Review

2020 ◽  
Vol 16 (4) ◽  
pp. 455-461
Author(s):  
Gabriela M. Baia ◽  
Otniel Freitas-Silva ◽  
Murillo F. Junior
Keyword(s):  
Chlorine Dioxide ◽  
Broad Spectrum ◽  
Fruits And Vegetables ◽  
Low Cost ◽  
Residual Effects ◽  
Pathogenic Microorganisms ◽  
Postharvest Diseases ◽  
Post Harvest ◽  
By Products

Fruits and vegetables are foods that come into contact with various types of microorganisms from planting to their consumption. A lack or poor sanitation of these products after harvest can cause high losses due to deterioration and/ or pathogenic microorganisms. There are practically no post-harvest fungicides or bactericides with a broad spectrum of action that have no toxic residual effects and are safe. However, to minimize such problems, the use of sanitizers is an efficient device against these microorganisms. Chlorine is the most prevalent sanitizing agent because of its broad spectrum, low cost and well-established practices. However, the inevitable formation of disinfection by-products, such as trihalomethanes (THMs) and haloacetic acids (HAAs), is considered one of the main threats to food safety. Alternative sanitizers, such as chlorine dioxide (ClO2) and ozone, are becoming popular as a substitute for traditional post-harvest treatments. Thus, this review addresses the use of chlorine, chlorine dioxide and ozone emphasizing aspects, such as usage, safe application, spectrum of action and legislation. In order to ensure the quality and safety of final products, the adoption of well-prepared sanitation and sanitation programs for post-harvest fruits and vegetables is essential.

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