• Journal of the Korean Electrochemical Society
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• v.6 no.3
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• pp.187-195
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• 2003

The present article is concerned with the overview of carbonaceous materials used as anode materials for lithium ion secondary batteries. This article first classified carbonaceous materials into graphite, soft carbon and hard carbon according to their crystal structures, and then summarised the previous works on the characteristics of lithium intercalation/deintercalation into/from the carbonaceous materials. Finally this article reviewed our recent research works on the mechanism of lithium transport through graphite, soft carbon and hard carbon electrodes from the kinetic view point by the analysis of the theoretical and experimental potentiostatic current transients.

• KSTLE International Journal
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• v.10 no.1_2
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• pp.43-47
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• 2009

Influences of carbonaceous ingredient as a solid lubricant in automotive friction materials on friction properties were studied. Three types of carbonaceous ingredients such as natural graphite, artificial graphite, and cokes were mixed using a constrained mixture design. A 1/5 scale brake dynamometer was used to obtain tribological properties. Results showed that cokes substantially increased the friction coefficient, and natural graphite effectively reduced stick-slip phenomena. This significant difference was attributed to the formation of the friction film on the brake pad which was shown to be strongly dependent on the graphite types. The different crystal structures of the carbonaceous solid lubricants played a significant role in the formation of friction film at the interface.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.42-45
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• 2005

Accurate prediction of the fate and transport of contaminants in soils and sediments is very Important to environmental risk assessment and effective remediation of contaminated soils and sediments. The fate and transport of contaminants in subsurface are affected by geosorbents, especially carbonaceous materials including black carbon. Various physical and chemical treatment methods have been developed to separate different kinds of carbonaceous materials from soils and sediments. However, the effects of these separation methods on the properties of remaining carbonaceous materials including sorption capacity and linearity are unclear. The objective of this study is to determine if the chemical and thermal treatment methods previously used to separate different carbonaceous material fractions affect the properties of carbonaceous materials including longer term sorption capacity of hydrophobic organic contaminants. The results indicate that treatments with hydrochloric acid (HCl)/hydrofluoric acid (HF), trifluoroacetic acid (TFA), sodium hydroxide (NaOH) may not affect the sorption capacity of black carbon reference materials such as char and soot, however, treatments with acid dichromate $(K_2Cr_2O_7/H_2SO_4)$ and heat $(375^{\circ}C)$ for 24 hours in sufficient of oxygen) decrease the sorption capacity of them. The results of longer term sorption isotherm indicate that 2 days might be enough for trichloroethene (TCE) to equilibrate apparently with treated black carbon reference materials. The results suggest that acid dichromate and heat treatments may not appropriate method to investigate sorption properties of black carbon in soils and sediments.

• Carbon letters
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• v.7 no.4
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• pp.249-258
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• 2006

Treatment of water hyacinth with sulphuric acid produces carbonaceous materials that have been used to remove Cu(II) and Cd (II) ions from aqueous solutions. Untreated water hyacinth was also used for the subject of comparison. The textural properties of the carbonaceous materials were determined from nitrogen adsorption at 77 K. The optimum pH for the sorption of Cu (II) and Cd (II) ions on the investigated sorbents was determined. Dynamic adsorption measurements have been taken at 298 K whereas equilibrium measurements were carried out at 298, 313 and 323 K. The adsorption of nitrogen at 77 K on the untreated sample was too low and the surface areas of the treated samples 2, 3 and 4 were found between $70-208\;m^2/g$. The total pore volumes of these samples which were determined for the carbonaceous materials investigated were found to be 0.076-0.140 ml/g. The kinetic adsorption data of Cu (II) and Cd(II) were applicable to both pseudo - first and pseudo-second order but fit more the latter order. The equilibrium adsorption data were found to fit Freundlich and Langmiur equations. The values of DG, DH and DS are all negative indicating the feasibility and the spontaneous nature of the sorption of Cu (II) and Cd (II) ions by the sorbents investigated.

• Journal of Electrochemical Science and Technology
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• v.15 no.3
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• pp.321-344
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• 2024

Transition metal compounds (TMCs) are being researched as promising electrode materials for electrochemical energy storage devices (supercapacitors). Among TMCs, transition metal phosphates (TMPs) have good, layered structures owing to open framework and protonic exchange capability among different layers, good surface area due to engrossed porosity, rich active redox reaction sites owing to octahedral structure and variable valance metallic ions. Hence TMPs become more ideal for supercapacitor electrode materials compared to other TMCs. However, TMPs have got some issues like low conductivity, rate performance, stability, energy, and power densities. But these problems can be addressed by making their composites with carbonaceous materials, e.g., carbon nanotubes (CNTs), graphene oxide (GO), graphitic carbon (GC), etc. A few factors like high surface area, excellent electrical conductivity of carbon materials and variable valence metal ions in TMPs caused great enhancement in their electrochemical performance. This article tries to discuss and compare the published data, majorly in last decade, regarding the electrochemical energy storage potential of pristine unary, binary, and ternary TMPs and their hybrid composites with carbonaceous materials (CNTs, GOs/rGOs, GC, etc.). The electrochemical performance of the hybrids has been reported to be higher than the pristine counterparts. It is hoped that the current review will open a new gateway to study and explore the high performance TMPs based supercapacitor materials.

• Applied Chemistry for Engineering
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• v.24 no.5
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• pp.489-493
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• 2013

The most common carbonaceous anode materials of lithium ion batteries (natural graphite, artificial graphite, hard carbon, and mesocarbon microbeads) were utilized as an electrode in lithium ion capacitors. It could be able to enhance the energy density of capacitors due to the intercalation of lithium ion. In this work, the properties of capacitors using the symmetric electrode were measured by organizing coin cell typed capacitors. Also, we made other capacitors having pre-intercalated lithium ions at one side of the electrode. The results of electrochemical measurements for these capacitors show that the storage capacitance was appeared. In other words, if the migration of lithium ions is supplied continuously in the electrolytes, lithium ions can be diffused into the carbonaceous materials. And it results in the improvement of capacitance compared to only using symmetric carbonaceous electrodes. Also, we conducted the same measurement with graphene oxide having a the large specific area in the same condition. Herein, we recognized that the large specific area is extremely important for supercapacitors.

• Transactions on Electrical and Electronic Materials
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• v.8 no.2
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• pp.97-102
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• 2007

The charging/discharging characteristics of electric double layer capacitors (EDLCs) for an electric power storage device application were investigated. The specific area of the carbonaceous electrode surface by the BET method was in the range of $1800{\sim}2000\;m^2/g$. The charge distributions during charging and discharging were measured by means of a pulsed-electro-acoustic (PEA) method, and the voltage characteristics of EDLCs connected to solar cells were evaluated. The results showed that the distributions of positive and negative charges were spatially uneven, which was due to the mobility of the positive and negative charges in the carbonaceous electrode surface of the EDLCs. The charge accumulation region concentrated on central part of the carbonaceous electrode and the required times for charging and discharging were almost same.

• Carbon letters
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• v.1 no.3_4
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• pp.170-177
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• 2001

Lithium intercalated carbon (LIC) are basically employed as an anode for currently commercialized lithium secondary batteries. However, there are still strong interests in modifying carbon surface of active materials of the anode because the amount of irreversible capacity, charge-discharge capacity and high rate capability are largely determined by the surface conditions of the carbon. In this study, the carbonaceous materials were coated with tin oxide and copper by fluidized-bed chemical vapor deposition (CVD) method and their coating effects on electrochemical characteristics were investigated. The electrode which coated with tin oxides gave the higher capacity than that of raw material. Their capacity decreased with the progress of cycling possibly due to severe volume changes. However, the cyclability was improved by coating with copper on the surface of the tin oxides coated carbonaceous materials, which plays an important role as an inactive matrix buffering volume changes. An impedance on passivation film was decreased as tin oxides contents and it resulted in the higher capacity.

• Composites Research
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• v.31 no.2
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• pp.76-81
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• 2018

In this study, the elemental mercury removal behaviors of silver-plated porous carbons materials were investigated. The pore structures and total pore volumes of the hybrid materials were analyzed by $N_2$ adsorption/desorption analysis at 77 K. The pore structures and surface morphologies of the hybrid materials were characterized by XRD and SEM, respectively. The elemental mercury adsorption capacities of all silver-plated porous carbons hybrid materials were higher than those of the as-received samples, despite the fact that the specific surface areas and total pore volumes decreased with increasing metal loading time. It was found that silver nanoparticles showed excellent elemental mercury removal behaviors in carbonaceous hybrid materials.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.7
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• pp.57-63
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• 2010

Photo-capacitor electrodes are attracting great attention because of their high capacitance and potential applications in electronic devices. Carbon capacitor, active carbon capacitor and its combination will be fabricated using a sandwich method as carbonaceous material on each type of storable electrode with $20{\times}15$[mm] cell size. Carbon/active carbon cell was fabricated using sol-gel process with $120[^{\circ}C]$ dry temperature in 2hour and using sintering process with $500[^{\circ}C]$ in 2hour. The effect of sintering temperature on carbon properties was also investigated with an X-ray diffraction technique to get the best sintering temperature. The detail of the fabrication process will be explained. Active carbon as carbonaceous material has a better capacitance in storable electrode with mean thickness $32[{\mu}m]$ and with particle size $1[{\mu}m]$ to $4.5[{\mu}m]$ in $20{\times}15$[mm] sample size of storable electrode.