scholarly journals Modified Activation Process for Supercapacitor Electrode Materials from African Maize Cob

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5412
Author(s):  
Moses Kigozi ◽  
Ravi Kali ◽  
Abdulhakeem Bello ◽  
Balaji Padya ◽  
Godwin Mong Kalu-Uka ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Photoelectron Spectroscopy ◽  
Electrode Materials ◽  
Chemical Activation ◽  
Mesoporous Structure ◽  
Activation Process ◽  
Energy Storage Devices ◽  
Supercapacitor Electrode ◽  
X Ray ◽  
Bet Analysis

In this work, African maize cobs (AMC) were used as a rich biomass precursor to synthesize carbon material through a chemical activation process for application in electrochemical energy storage devices. The carbonization and activation were carried out with concentrated Sulphuric acid at three different temperatures of 600, 700 and 800 °C, respectively. The activated carbon exhibited excellent microporous and mesoporous structure with a specific surface area that ranges between 30 and 254 m2·g−1 as measured by BET analysis. The morphology and structure of the produced materials are analyzed through Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Boehm titration, X-ray Photoelectron Spectroscopy (XPS) and Raman Spectroscopy. X-ray photoelectron spectroscopy indicates that a considerable amount of oxygen is present in the materials. The functional groups in the activated carbon enhanced the electrochemical performance and improved the material’s double-layer capacitance. The carbonized composite activated at 700 °C exhibited excellent capacitance of 456 F g−1 at a specific current of 0.25 A g−1 in 6 M KOH electrolyte and showed excellent stability after 10,000 cycles. Besides being a low cost, the produced materials offer good stability and electrochemical properties, making them suitable for supercapacitor applications.

scholarly journals Comparison of Surface and Structural Properties of Carbonaceous Materials Prepared by Chemical Activation of Tomato Paste Waste: The Effects of Activator Type and Impregnation Ratio

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Nurgul Ozbay ◽  
Adife Seyda Yargic
Keyword(s):  
Activated Carbon ◽  
Activated Carbons ◽  
Low Cost ◽  
Chemical Activation ◽  
Nitrogen Adsorption ◽  
Xrd Analysis ◽  
Point Of Zero Charge ◽  
Activation Process ◽  
X Ray ◽  
Tomato Paste

Activated carbons were prepared by carbonization of tomato paste processing industry waste at 500°C followed by chemical activation with KOH, K2CO3, and HCl in N2 atmosphere at low temperature (500°C). The effects of different activating agents and impregnation ratios (25, 50, and 100 wt.%) on the materials’ characteristics were examined. Precursor, carbonized tomato waste (CTW), and activated carbons were characterized by using ultimate and proximate analysis, thermogravimetric analysis (TG/DTG), Fourier transform-infrared (FT-IR) spectroscopy, X-ray fluorescence (XRF) spectroscopy, point of zero charge measurements (pHPZC), particle size analyzer, scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, nitrogen adsorption/desorption isotherms, and X-ray diffraction (XRD) analysis. Activation process improved pore formation and changed activated carbons’ surface characteristics. Activated carbon with the highest surface area (283 m3/g) was prepared by using 50 wt.% KOH as an activator. According to the experimental results, tomato paste waste could be used as an alternative precursor to produce low-cost activated carbon.

scholarly journals Three-dimensional pore structure of activated carbon monolithic derived from hierarchically bamboo stem for supercapacitor application

2020 ◽  
Vol 5 (1) ◽  
pp. 22-30 ◽  
Author(s):  
Erman Taer ◽  
Lini Pratiwi ◽  
Apriwandi Apriwandi ◽  
Widya Sinta Mustika ◽  
Rika Taslim ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Electrochemical Performance ◽  
Pore Structure ◽  
Chemical Activation ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Supercapacitor Electrode ◽  
X Ray ◽  
Supercapacitor Application ◽  
Bamboo Stem

A three-dimensional pore structure on activated carbon derived from hierarchically bamboo stem was synthesized in the monolithic form for increased applicability as a supercapacitor electrode. The preparation involved two step carbonizations, using a chemical activation at different concentrations. Subsequently, the morphology, chemical content, specific surface area and pore size distribution, as well as crystalline degree were evaluated with scanning electron microscopy, energy X-ray (EDX), N2 sorption and X-ray diffraction, respectively. Therefore, cyclic voltammetry (CV) was used to assess the electrochemical performance, in a two electrode system. The result shows the significant impact of the three-dimensional structure on electrochemical performance, and the optimized sample exhibited specific capacitance of 168.8 F g-1, energy density of 23.44 Wh kg-1, and power density of 84.46 W kg-1.

Nanostructured manganese oxides and their composites with carbon nanotubes as electrode materials for energy storage devices

2008 ◽  
Vol 80 (11) ◽  
pp. 2327-2343 ◽  
Author(s):  
V. Subramanian ◽  
Hongwei Zhu ◽  
Bingqing Wei
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Photoelectron Spectroscopy ◽  
Manganese Oxides ◽  
Electrode Materials ◽  
Electrochemical Impedance ◽  
Analytical Techniques ◽  
Energy Storage Devices ◽  
X Ray ◽  
Storage Devices

Manganese oxides have been synthesized by a variety of techniques in different nanostructures and studied for their properties as electrode materials in two different storage applications, supercapacitors (SCs) and Li-ion batteries. The composites involving carbon nanotubes (CNTs) and manganese oxides were also prepared by a simple room-temperature method and evaluated as electrode materials in the above applications. The synthesis of nanostructured manganese oxides was carried out by simple soft chemical methods without any structure directing agents or surfactants. The prepared materials were well characterized using different analytical techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), surface area studies, etc. The electrochemical properties of the nanostructured manganese oxides and their composites were studied using cyclic voltammetry (CV), galvanostatic charge-discharge, and electrochemical impedance spectroscopic (EIS) studies. The influence of structural/surface properties on the electrochemical performance of the synthesized manganese oxides is reviewed.

Preparation of Capacitor’s Electrode from Coconut Shell

2014 ◽  
Vol 875-877 ◽  
pp. 1585-1589
Author(s):  
Arenst Andreas Arie ◽  
Joong Kee Lee
Keyword(s):  
Activated Carbon ◽  
Surface Area ◽  
Electrode Materials ◽  
Activated Carbons ◽  
Chemical Activation ◽  
Coconut Shell ◽  
Bet Surface Area ◽  
Type I ◽  
Activation Temperature ◽  
Bet Analysis

Activated carbons were prepared from coconut shell by chemical activation method and utilized as electrode materials for electrochemical double layer capacitor (EDLC). A preliminary characteristic of activated carbon from coconut shell includes the Brunnaeur Emmett Teller (BET) analysis and cyclic voltammetry measurements. The BET surface area is not affected by the variation of activation temperature as both of the samples showed BET surface area of about 850-870 m2g-1. The N2 adsorption–desorption isotherms showed that the sample exhibited type I characteristics according to IUPAC classification, which confirms its micro-porosity. Compared with the un-activated carbon samples, the activated ones exhibited the better electrochemical properties with a specific capacitance of 150 F g−1 at a scan rate of 2 mV s−1. The good performance of activated carbon is attributed to the enhancement of surface area due to the KOH pretreatment which can open new pores accessible for the ionic transport

Porous Carbon/CeO2 Nanoparticles Hybrid Material for High-Capacity Super-Capacitors

MRS Advances ◽  
2017 ◽  
Vol 2 (46) ◽  
pp. 2471-2480 ◽  
Author(s):  
Hoejin Kim ◽  
Mohammad Arif Ishtiaque Shuvo ◽  
Hasanul Karim ◽  
Manjula I Nandasiri ◽  
Ashleigh M Schwarz ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hybrid Material ◽  
Porous Carbon ◽  
Photoelectron Spectroscopy ◽  
Electrode Materials ◽  
Material System ◽  
Ultrahigh Energy ◽  
Energy Storage Devices ◽  
X Ray ◽  
Super Capacitors

ABSTRACTThe increasing demand for energy storage devices has propelled research for developing efficient super-capacitors (SC) with long cycle life and ultrahigh energy density. Carbon-based materials are commonly used as electrode materials for SC. Herein, we report a new approach to improve the SC performance utilizing a Porous Carbon/Cerium Oxide nanoparticle (PC-CON) hybrid as electrode material synthesized via a low temperature hydrothermal method. Through this approach, charges can be stored not only via electrochemical double layer capacitance (EDLC) from PC but also through pseudo-capacitive effect from CeO2 nanoparticles (NPs). The electrode-electrolyte interaction due to the electrochemical properties of the electrolyte provides an enhanced voltage window for the SC. Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), and X-Ray Diffraction (XRD) measurements were used for the characterization of this PC/CeO2 hybrid material system. The testing results have shown that a maximum of 500% higher specific capacitance could be obtained using PC/CeO2 instead of using PC only.

scholarly journals Lanthanum-doped activated carbon derived from municipal sludge for enhanced defluoridation: characteristics and mechanism

2020 ◽  
Vol 82 (8) ◽  
pp. 1643-1652
Author(s):  
Lizhi He ◽  
Guoqiao Wang ◽  
Xinxin Zhang ◽  
Yujian Zhang ◽  
Yao Chen
Keyword(s):  
Activated Carbon ◽  
Photoelectron Spectroscopy ◽  
Removal Rate ◽  
Chemical Activation ◽  
Fluoride Concentration ◽  
Stability Study ◽  
Fluoride Removal ◽  
Municipal Sludge ◽  
Treatment Rate ◽  
X Ray

Abstract The sewage sludge production has been increasing along with the ever-growing populations and wastewater treatment rate. Lanthanum-doped activated carbon (AC-La) was derived from municipal sludge via chemical activation and utilized for fluoride removal. Batch experiments were conducted to discuss the effect of lanthanum dosage, time and pH on the adsorption process. The results showed that 4 g/L AC-La exhibited a fluoride removal rate of 80.9% with 10 mg/L initial fluoride concentration, and the optimal pH range for adsorption was 3–10. X-ray fluorescence, scanning electron microscopy with energy-dispersive X-ray spectroscopy, Brunauer-Emmett-Teller, X-ray diffraction, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses were conducted to analyze the microstructure and chemical properties of sludge, unmodified activated carbon (AC) and AC-La. The results showed that with initial lanthanum dosage of 15 wt%, the final loading amount of La in AC-La was 13.8 wt%. After modification, the specific surface area of AC-La increased from 1.8 m2/g (sludge) to 133.0 m2/g. The removal mechanism of fluoride onto AC-La was mainly the inner-sphere complexation between lanthanum and fluoride, facilitated by exchange interaction with hydroxyls. A stability study showed that AC-La maintained a quite small dissolution and was safe in waters (La dissolution rate < 0.2‰).

Hydrothermal Synthesis of Cobalt Ruthenium Sulfides as Promising Pseudocapacitor Electrode Materials

Coatings ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 200 ◽  
Author(s):  
Ravi Bolagam ◽  
Sukkee Um
Keyword(s):  
Photoelectron Spectroscopy ◽  
High Performance ◽  
Electrode Materials ◽  
Electrochemical Impedance ◽  
Rate Capability ◽  
Metal Sulfide ◽  
Energy Storage Devices ◽  
X Ray ◽  
Storage Devices ◽  
Ternary Metal

In this paper, we report the successful synthesis of cobalt ruthenium sulfides by a facile hydrothermal method. The structural aspects of the as-prepared cobalt ruthenium sulfides were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy. All the prepared materials exhibited nanocrystal morphology. The electrochemical performance of the ternary metal sulfides was investigated by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy techniques. Noticeably, the optimized ternary metal sulfide electrode exhibited good specific capacitances of 95 F g−1 at 5 mV s−1 and 75 F g−1 at 1 A g−1, excellent rate capability (48 F g−1 at 5 A g−1), and superior cycling stability (81% capacitance retention after 1000 cycles). Moreover, this electrode demonstrated energy densities of 10.5 and 6.7 Wh kg−1 at power densities of 600 and 3001.5 W kg−1, respectively. These attractive properties endow proposed electrodes with significant potential for high-performance energy storage devices.

scholarly journals Pseudocapacitive Effect of Carbons Doped with Different Functional Groups as Electrode Materials for Electrochemical Capacitors

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5577
Author(s):  
Mojtaba Mirzaeian ◽  
Qaisar Abbas ◽  
Michael. R. C. Hunt ◽  
Peter Hall
Keyword(s):  
Activated Carbon ◽  
Photoelectron Spectroscopy ◽  
Nitrogen Doping ◽  
Electrode Materials ◽  
Carbon Matrix ◽  
Fold Increase ◽  
Xrd Analysis ◽  
Carbon Aerogels ◽  
Nitrogen Doped ◽  
Bet Analysis

In this study, RF-based un-doped and nitrogen-doped aerogels were produced by polymerisation reaction between resorcinol and formaldehyde with sodium carbonate as catalyst and melamine as the nitrogen source. Carbon/activated carbon aerogels were obtained by carbonisation of the gels under inert atmosphere (Ar) followed by activation of the carbons under CO2 at 800 °C. The BET analysis of the samples showed a more than two-fold increase in the specific Surf. area and pore volume of carbon from 537 to 1333 m2g−1 and 0.242 to 0.671 cm3g−1 respectively after nitrogen doping and activation. SEM and XRD analysis of the samples revealed highly porous amorphous nanostructures with denser inter-particle cross-linked pathways for the activated nitrogen-doped carbon. The X-Ray Photoelectron Spectroscopy (XPS) results confirmed the presence of nitrogen and oxygen heteroatoms on the Surf. and within the carbon matrix where improvement in wettability with the drop in the contact angle from 123° to 80° was witnessed after oxygen and nitrogen doping. A steady drop in the equivalent series (RS) and charge transfer (RCT) resistances was observed by electrochemical measurements after the introduction of nitrogen and oxygen heteroatoms. The highest specific capacitance of 289 Fg−1 with the lowest values of 0.11 Ω and 0.02 Ω for RS and RCT was achieved for nitrogen and oxygen dual-doped activated carbon in line with its improved Surf. chemistry and wettability, and its enhanced conductivity due to denser inter-particle cross-linked pathways.

scholarly journals Synthesis and Electrochemical Study of Three-Dimensional Graphene-Based Nanomaterials for Energy Applications

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1295
Author(s):  
Antony R. Thiruppathi ◽  
Boopathi Sidhureddy ◽  
Emmanuel Boateng ◽  
Dmitriy V. Soldatov ◽  
Aicheng Chen
Keyword(s):  
Energy Storage ◽  
Energy Conversion ◽  
Photoelectron Spectroscopy ◽  
Electrode Materials ◽  
High Surface ◽  
Three Dimensional ◽  
Reduction Reaction ◽  
Chemical Compositions ◽  
Supercapacitor Electrode ◽  
X Ray

Graphene is an attractive soft material for various applications due to its unique and exclusive properties. The processing and preservation of 2D graphene at large scales is challenging due to its inherent propensity for layer restacking. Three-dimensional graphene-based nanomaterials (3D-GNMs) preserve their structures while improving processability along with providing enhanced characteristics, which exhibit some notable advantages over 2D graphene. This feature article presents recent trends in the fabrication and characterization of 3D-GNMs toward the study of their morphologies, structures, functional groups, and chemical compositions using scanning electron microscopy, X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. Owing to the attractive properties of 3D-GNMs, which include high surface areas, porous structures, improved electrical conductivity, high mechanical strength, and robust structures, they have generated tremendous interest for various applications such as energy storage, sensors, and energy conversion. This article summarizes the most recent advances in electrochemical applications of 3D-GNMs, pertaining to energy storage, where they can serve as supercapacitor electrode materials and energy conversion as oxygen reduction reaction catalysts, along with an outlook.

scholarly journals Computer Analysis of the Effect of Activation Temperature on the Microporous Structure Development of Activated Carbon Derived from Common Polypody

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2951
Author(s):  
Mirosław Kwiatkowski ◽  
Jarosław Serafin ◽  
Andy M. Booth ◽  
Beata Michalkiewicz
Keyword(s):  
Activated Carbon ◽  
Porous Structure ◽  
Computer Analysis ◽  
Density Functional ◽  
Activated Carbons ◽  
Chemical Activation ◽  
Geometrical Parameters ◽  
Activation Process ◽  
Microporous Structure ◽  
Activation Temperature

This paper presents the results of a computer analysis of the effect of activation process temperature on the development of the microporous structure of activated carbon derived from the leaves of common polypody (Polypodium vulgare) via chemical activation with phosphoric acid (H3PO4) at activation temperatures of 700, 800, and 900 °C. An unconventional approach to porous structure analysis, using the new numerical clustering-based adsorption analysis (LBET) method together with the implemented unique gas state equation, was used in this study. The LBET method is based on unique mathematical models that take into account, in addition to surface heterogeneity, the possibility of molecule clusters branching and the geometric and energy limitations of adsorbate cluster formation. It enabled us to determine a set of parameters comprehensively and reliably describing the porous structure of carbon material on the basis of the determined adsorption isotherm. Porous structure analyses using the LBET method were based on nitrogen (N2), carbon dioxide (CO2), and methane (CH4) adsorption isotherms determined for individual activated carbon. The analyses carried out showed the highest CO2 adsorption capacity for activated carbon obtained was at an activation temperature of 900 °C, a value only slightly higher than that obtained for activated carbon prepared at 700 °C, but the values of geometrical parameters determined for these activated carbons showed significant differences. The results of the analyses obtained with the LBET method were also compared with the results of iodine number analysis and the results obtained with the Brunauer–Emmett–Teller (BET), Dubinin–Radushkevich (DR), and quenched solid density functional theory (QSDFT) methods, demonstrating their complementarity.

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