• 한국전기화학회:학술대회논문집
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• 2005.04a
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• pp.43-43
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• 2005

• Transactions of the Korean hydrogen and new energy society
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• v.23 no.5
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• pp.503-512
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• 2012

There is a new power generation system such as direct coal fuel cell (DCFC) with a solid oxide electrolyte operated at relatively high temperature. In the system, it is of great importance to feed coal continuously into anodic electrode surface for its better contact, otherwise it would reduce electrochemical conversion of coal. For that purpose, it is required to improve the electrochemical conversion efficiency by using either rigorous mixing condition such as fluidized bed condition or just by recirculating coal particle itself successively into the reaction zone of the system. In this preliminary study, we followed the second approach to investigate how significantly particle recycle would affect the coal conversion efficiency. As a first phase, coal conversion was analyzed and evaluated from the thermochemical reaction of carbon with air under particle recirculating condition. The coal conversion efficiency was obtained from raw data measured by two different techniques. Effects of temperature and fuel properties on the coal conversion are specifically examined from the thermochemical reaction.

• Journal of the Korean Electrochemical Society
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• v.10 no.2
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• pp.141-144
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• 2007

Polypyrrole(PPy) was composite with MWNT to attain cycle stable by chemical method. We have been considered PPy is the ideal material for high energy density electrochemical capacitor due to pseudo capacitor reaction. In this study we found that increase in cycle life due to composite MWNT. Also PPy/MWNT composite material have resulted larger capacitance and exhibits better electrochemical behavior. The structural feature was investigated by using SEM and TEM. The PPy/CNT composite is not only a promising ultracapacitor material for energy storages but also has a good possibility because of its great capacitive properties, simple preparation and low cost.

• Journal of Electrochemical Science and Technology
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• v.10 no.2
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• pp.185-195
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• 2019

The large surface area and the high electrical conductivity of graphene (GP) allow it to act as an "electron wire" between the redox center of biomolecules and an electrode surface. The faster electron transfer kinetics and excellent catalytic activity of GP facilitate the accurate and selective electrochemical detection of biomolecules. This mini-review provides an overview of the recent developments and progress of GP, functionalized or doped GP, and GP-composites based sensors for the selective and interference-free detection of dopamine (DA). The electrochemical principles and future perspective and challenges of DA sensors were also discussed based on GP.

• Journal of Electrochemical Science and Technology
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• v.8 no.3
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• pp.250-256
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• 2017

A graphene electrode with a novel in-plane structure is proposed and successfully adopted for use in supercapacitor applications. The in-plane structure allows electrolyte ions to interact with all the graphene layers in the electrode, thereby maximizing the utilization of the electrochemical surface area. This novel structure contrasts with the conventional out-of-plane stacked structure of such supercapacitors. We herein compare the volumetric capacitances of in-plane- and out-of-plane-structured devices with reduced multi-layer graphene oxide films as electrodes. The in-plane-structured device exhibits a capacitance 2.5 times higher (i.e., $327F\;cm^{-3}$) than that of the out-of-plane-structured device, in addition to an energy density of $11.4mWh\;cm^{-3}$, which is higher than that of lithium-ion thin-film batteries and is the highest among in-plane-structured ultra-small graphene-based supercapacitors reported to date. Therefore, this study demonstrates the potential of in-plane-structured supercapacitors with high volumetric performances as ultra-small energy storage devices.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.276-276
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• 2006

The incorporation of room temperature ionic liquids (IL) in poly (ethyleneoxide)-lithium salt (PEO-LiX) based solid polymer electrolytes is presently being studied as an effective means of enhancing the room temperature ionic conductivity of these electrolytes to acceptable levels for use in lithium batteries. In the present study, $PEO_{20}-LiTFSI$ solid polymer electrolyte was blended with three different ionic liquids, namely 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (BMIMTFSI), 1-butyl-3-methylimidazolium tetraflouroborate (BMIMBF4) and 1-butyl-3-methylimidazolium trifluromethanesulfonate ($BMIMCF_{3}SO_{3}$). The incorporation of all these ILs resulted in the enhancement of ionic conductivity, the effect being more pronounced at lower temperatures. Electrochemical properties of the blended electrolytes were studied by cyclic voltammetry, linear sweep voltammetry and interfacial resistance measurements. The optimum results were obtained with the blending of BMIMTFSI in the solid polymer electrolyte.

• Bulletin of the Korean Chemical Society
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• v.28 no.8
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• pp.1329-1334
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• 2007

The electrochemical oxidation of cerium(III) was carried out using divided and undivided electrochemical cells in nitric acid medium. It was found that divided cell with Nafion 324 as the separator gave good conversion yield with high current efficiency compared to the undivided cell. The efficiency of the divided electrochemical cell was further optimized in terms of cell voltage, temperature, flow rate of solution recirculation, concentrations of Ce(III) and nitric acid. The better conditions for 1 M Ce(III) in 3 M nitric acid were found to be 2.5 V, 363 K and 100 mL/min recirculation flow rate based on the current efficiency under the experimental conditions investigated. The Ce(IV) oxidant produced was used as a mediator for the mineralization of phenol. The mineralization efficiency of the cerium mediated electrochemical oxidation was found rapid and higher compared to the direct electrochemical oxidation based on CO2 evolution under the same conditions.

• Journal of Electrochemical Science and Technology
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• v.12 no.2
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• pp.279-284
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• 2021

The high theoretical specific capacity of lithium-sulfur (Li-S) batteries makes them a more promising energy storage system than conventional lithium-ion batteries (LIBs). However, the slow kinetics of the electrochemical conversion reaction seriously hinders the utilization of Li-S as an active battery material and has prevented the successful application of Li-S cells. Therefore, exploration of alternatives that can overcome the sluggish electrochemical reaction is necessary to increase the performance of Li-S batteries. In this work, an ionic liquid (IL) is proposed as a functional additive to promote the electrochemical reactivity of the Li-S cell. The sluggish electrochemical reaction is mainly caused by precipitation of low-order polysulfide (l-PS) onto the positive electrode, so the IL is adopted as a solubilizer to remove the precipitated l-PS from the positive electrode to promote additional electron transfer reactions. The ILs effectively dissolve l-PS and greatly improve the electrochemical performance by allowing greater utilization of l-PS, which results in a higher initial specific capacity, together with a moderate retention rate. The results presented here confirmed that the use of an IL as an additive is quite effective at enhancing the overall performance of the Li-S cell and this understanding will enable the construction of highly efficient Li-S batteries.

• Journal of the Korean Electrochemical Society
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• v.21 no.4
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• pp.68-79
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• 2018

Currently, hybridization of energy generator and storage devices is considered to be one of the most important energy-related technologies due to the possibility of replacing batteries or extending the lifetime of a batteries in accordance with increasing battery demand. This review aims to describe current progress on the mechanical energy generator and hybridization of energy generator and energy storage devices for self-powered electronics. First, the research trends related to energy generation devices using piezoelectric and triboelectric effect that convert physical energy into electric energy is introduced. In addition, integration of energy generators and energy storage devices is introduced. In particular, self-charging energy cells provide an innovative approach to the direct conversion of mechanical energy into electrochemical energy to decrease energy conversion loss.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.5
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• pp.335-340
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• 2018

Transition metal oxide materials have attracted widespread attention as Li-ion battery electrode materials owing to their high theoretical capacity and good Li storage capability, in addition to various nanostructured materials. Here, we fabricated a CoO Li-ion battery in which Co nanoparticles (NPs) are deposited into a current collector through electrophoretic deposition (EPD) without binding and conductive agents, enabling us to focus on the intrinsic electrochemical properties of CoO during the conversion reaction. Through optimized Co NP synthesis and electrophoretic deposition (EPD), CoO Li-ion battery with 630 mAh/g was fabricated with high cycle stability, which can potentially be used as a test platform for a fundamental understanding of conversion reaction.