• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.76-79
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• 2004

This research was carried out to evaluate role of supplementary reagents, such as phosphate and SDS, to remove hydrophobic organic contaminant from soils during the EK-Fenton process. The $H_2O$$_2$ stability improved due to the role as stabilizer of phosphate and SDS during the EK-Fenton process. Furthermore, although pH in region near cathode was 8.2 after test, $H_2O$$_2$ stability improved due to transportation of SDS in the region near cathode. Therefore, in tests using phosphate and SDS as supplementary reagent, the efficiency of phenanthrene treatment improved through the EK-Fenton process using longer reaction time.

• Transactions on Electrical and Electronic Materials
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• v.13 no.3
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• pp.121-124
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• 2012

Olivine type $LiFePO_4$ cathode material was synthesized by solid-state reaction method including one-step heat treatment. To improve the electrochemical characteristics, graphite nanofiber (GNF) was added into $LiFePO_4$ cathode material. The structure and morphological performance of $LiFePO_4$ were investigated by X-ray diffraction (XRD); and a field emission-scanning electron microscope (FE-SEM). The synthesized $LiFePO_4$ has an olivine structure with no impurity, and the average particle size of $LiFePO_4$ is about 200~300 nm. With graphite nanofiber added, the discharge capacity increased from 113.43 mAh/g to 155.63 mAh/g at a current density of 0.1 $mA/cm^2$. The resistance was also significantly decreased by the added graphite nanofiber.

• Bulletin of the Korean Chemical Society
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• v.22 no.12
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• pp.1328-1332
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• 2001

The structure and electrochemical properties of the LixCoyNi1-yO2 (y=0.1, 0.3, 0.5, 0.7, 1.0) system synthesized by solid state reaction with various starting materials have been investigated to optimize the characteristics and synthetic conditions of the LixCoyNi1-yO2. The first discharge capacities of LixCoyNi1-yO2 are 60 mAh/g-180 mAh/g with synthetic conditions. Among them, the LixNi0.7Co0.3O2, which was prepared with LiOH, NiO, and Co3O4 at $850^{\circ}C$, had the best electrochemical properties. The first discharge capacity of the compound was 180 mAh/g.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2018.05a
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• pp.51-52
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• 2018

Selective oxidation of RE elements from the U/RE metal ingot was studied in this paper using electrochemical process. Constant potential of -1.7V was applied between anode and cathode, where the potential value corresponds to standard potentials between actinide and rare earth materials. When the current values approached to nearly 0 mA, the reaction was finished. It is confirmed from the EPMA analysis that only U part of the U/RE ingot was remained. The metal recovered to the zinc cathode was obtained through the distillation process and it is being chemically analyzed in the KAERI analytical laboratory.

• Journal of Electrochemical Science and Technology
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• v.15 no.1
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• pp.161-167
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• 2024

Despite the important role of manganese (Mn) in cobalt-free, Ni-rich cathode materials, existing reports on the effects of Mn as a substitute for cobalt are not consistent. In this work, we analyzed the performance of cathodes comprised of Li(Ni_1-xMn_x)O₂ (LNMO). Both beneficial and detrimental results occurred as a result of the Mn substitution. We found that a complex interplay of effects (Li/Ni mixing driven by magnetic frustration, grain growth suppression, and retarded lithium insertion/extraction kinetics) influenced the performance and was intimately related to calcination temperature. This indicates the importance of establishing an optimal reaction temperature for the development of high-performance LNMO.

• Journal of the Korean Electrochemical Society
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• v.14 no.2
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• pp.110-116
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• 2011

Ru black was used for cathode catalyst in polymer electrolyte membrane fuel cell which showed low performance at the initial test. However, it was observed that the performance of Ru black cathode was dramatically enhanced after certain kind of experiment compared with initial one. It might be due to an electrochemical treatment in which a voltage was applied to the Ru cathode for constant period time. When a constant potential of 0.1 V was applied to Ru cathode for 30 min, the fuel cell performance of Ru cathode showed the best results. In order to investigate the effect of electrochemical treatment on the performance enhancement, the characteristics of electrochemically treated Ru black was compared with that of Ru black which was reduced under $H_2$ atmosphere. From XRD results, it was turned out that Ru black was not completely converted to metallic Ru by electrochemical treatment, but it is sufficient to be one of reasons for the performance enhancement. According to the results of CO stripping voltammetry, it was observed that some Ru was removed from Ru electrode by electrochemical treatment which might have a bad effect on the fuel cell performance. The removal of some Ru from as-received Ru black by electrochemical treatment is also another reason for the enhancement of fuel cell performance.

• Journal of the Korean Electrochemical Society
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• v.19 no.1
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• pp.1-8
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• 2016

Capacity of layered lithium nickel-cobalt-manganese oxide ($LiNi_{1-x-y}Co_xMn_yO_2$) cathode material can increase by raising the charge cut-off voltage above 4.3 V vs. $Li/Li^+$, but it is limited due to anodic instability of conventional electrolyte. We have been screening and evaluating various sulfone-based compounds of dimethyl sulfone (DMS), diethyl sulfone (DES), ethyl methyl sulfone (EMS) as electrolyte additives for high-voltage applications. Here we report improved cycling performance of $LiNi_{0.5}Co_{0.2}Mn_{0.3}O_2$ cathode by the use of dimethyl sulfone (DMS) additive under an aggressive charge condition of 4.6 V, compared to that in conventional electrolyte, and cathode-electrolyte interfacial reaction behavior. The cathode with DMS delivered discharge capacities of $198-173mAhg^{-1}$ over 50 cycles and capacity retention of 84%. Surface analysis results indicate that DMS induces to form a surface protective film at the cathode and inhibit metal-dissolution, which is correlated to improved high-voltage cycling performance.

• Journal of Sensor Science and Technology
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• v.17 no.1
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• pp.9-14
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• 2008

In this paper, the gas responses of tungsten oxide films prepared by anodic reaction was discussed. Sensing electrodes and heating electrodes were patterned by photolithography method on quartz substrate. Porous tungsten oxide was fabricated in electrolyte solutions of 5 % HF (HF :$C_2H_6OH:H_2O$=3 : 2 : 20) by anodic reaction. The anodic reaction with metal (platinum wire) as a cathode and the sensing device as an anode was conducted under the various reaction times (1-10 min) at 10 mA/$cm^2$ The surface structure and morphology of the fabricated sensor have been analysed by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM). All the peaks of XRD results were well indexed to the pure phase pattern. The average diameter of the porous tungsten oxide surface were ranged about 100 nm. The fabricaed sensor showed good sensitivity to 200 ppm toluene at operating temperature of $250^{\circ}C$.

• Journal of the Korean institute of surface engineering
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• v.21 no.4
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• pp.160-167
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• 1988

Electrochemical behaviors od chromium electrodeposition from 0.05M chromium (III) sulface complexes in aqueous solutions using sodium formate-glycine mixtures as a complexing agent were studied. In the cathodic current-potential cures, it is found that the intial limiting current of Cr(III) is proportional to square root of scan rate and activiation energy from Arrhenius plot is s obtained 3.05Kcal/mol. From this results, the reaction is considered, Cr3++e longrightarrow Cr2+, which is controlled diffusion of Cr (III). It is also found that the chromium is deposited when the potential reaches to hydrogen evolution potential. Effects of NaSCN as a catalyser in the electrolyte were investigated NCS- anion seems to react strongly by specific absorption at the inner HelmholtZ layer, so that, it is considered to suppress the electrodeposition reaction reaction for chromjum, and also it is considered multipe-bridge such as Cr(III)-NCS---M(M;cathode).

• Ceramist
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• v.21 no.4
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• pp.416-426
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• 2018

Water splitting is regarded as one of the most environmentally benign routes for hydrogen production. Nevertheless, the low energy efficiency to produce the hydrogen has been a critical bottleneck, which is attributable to the multi-electron and multi-step reactions during water splitting reaction. In this respect, the development of efficient, durable, and inexpensive catalysts that can promote the reaction is indispensable. Extensive searching for new catalysts has been carried out for past decades, identifying several promising catalysts. Recently, researchers have found that conventional battery materials; particularly high-voltage intercalation-based cathode materials, could exhibit remarkable performance in catalyzing the water splitting process. One of the unique capabilities in this class of materials is that the valency state of metals and the atomic arrangement of the structure can be easily tailored, based on simple intercalation chemistry. Moreover, taking advantage of the rich prior knowledge on the intercalation compounds can offer the unexplored path to identify new water splitting catalysts.