• Journal of the Korean Electrochemical Society
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• v.6 no.4
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• pp.242-249
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• 2003

Zn electrode was widely used as an anode material in alkaline battery systems in highly concentrated KOH electrolyte, however it was well known that its cycle life is significantly shortened by growth of dendrite due to the high dissolution of $Zn(OH)_2$ and rapid electrochemical reaction. In this study when by the additives such as $Ca(OH)_2$, Citrate, tartrate and Gluconate were added to $40\%$ KOH electrolyte at solution temperature of $25^{\circ}C$ and the amount of $5wt\%\;Pb_3O_4$ was mixed to Zn electrode and then the effect of $Pb_3O_4$ and additives on the electrochemical behavior of Zn electrode was investigated by Potentiodynamic Polarization Curves, Cyclic Voltammetry, Accelerated Life Cycle lest, and SEM image analyses. The addition of $Pb_3O_4$ reduced the corrosion rate of Zn electrode. The corrosion potential of Zn electrode with $Pb_3O_4$ was higher or lower than that of pure Zn electrode however was not influenced practically to the open circuit voltage. And the addition of 4 type additives had an important role in improving both cycle life in accelerated cycle life test and corrosion resistance. Furthermore the additive of Tartrate indicated comparatively a good effect to corrosion resistance as well as charging-discharging property Improvement among those four type additives.

• Korean Chemical Engineering Research
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• v.56 no.5
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• pp.718-724
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• 2018

In this study, the $Ni_{0.9}Co_{0.05}Ti_{0.05}(OH)_2$ precursor was prepared by the concentration gradient co-precipitation method. In order to overcome the structural change due to oxygen desorption in the cathode active material with high nickel content, the physical and electrochemical analysis of the cathode active material according to the calcination temperature were investigated. Physical properties of $Li_{1.05}Ni_{0.9}Co_{0.05}Ti_{0.05}O_2$ were analyzed by FE-SEM, XRD and TGA. The electrochemical performance of the coin cell using a cathode active material and $LiPF_6$(EC:EMC=1:2 vol%) electrolyte was evaluated by the initial charge/discharge efficiency, cycle retention, and rate capabilities. As a result, the initial capacity and initial efficiency of cathode materials were excellent with 244.5~247.9 mAh/g and 84.2~85.8% at the calcination temperature range of $750{\sim}760^{\circ}C$. Also, the capacity retention exhibited high stability of 97.8~99.1% after 50cycles.

• Polymer(Korea)
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• v.35 no.6
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• pp.593-598
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• 2011

The IPA-co-HDO-co-(TPA/MA) copolymers for all-vanadium redox flow battery were synthesized by melt condensation polymerization using isophthalic acid(IPA), 1,6-hexandiol (HDO), terephthalic acid(TPA) and maleic anhydride(MA). The amination of chloromethylated IPA-co- HDO-co-(TPA/MA)(CIHTM) copolymer was carried out using trimethylamine, and the anion exchange membrane was also prepared by UV crosslinking reaction. The structure and thermal stability of IHTM copolymers were confirmed by FTIR, $^1H$ NMR, and TGA analysis. The anion membrane properties such as water uptake, ion exchange capacity, electric resistance and electrical conductivity, were measured by gravimetry, titration and LCR meter. The efficiency of the all-vanadium redox flow battery was analyzed. The ion exchange capacity, electric resistance and electrical conductivity were 1.10 meq/g, $1.98{\Omega}{\cdot}cm^2$, and 0.009 S/cm, respectively. The efficiency of charge-discharge, voltage, and energy for the allvanadium redox flow battery were 96.5, 74.6, 70.0%, respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.12
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• pp.2335-2342
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• 2007

Laser stimulation has been widely studied and used in clinic. However, electrical response by laser stimulation on meridians has not been investigated. In this study, we compared electric potential of laser and acupuncture stimulation on meridians. We measured electric potential variation at acupoints(Samgan(LI3) and Hapgok(LI4)) on Large Intestine Meridian. In laser stimulation results, average peak electric potential is very low($7.53{\pm}3.44{\mu}V$) for before and after stimulation. However, acupuncture stimulation was performed in ground connection condition and resulted in huge variation of average peak electric potential($2.65{\pm}1.53mV$). That is, the intensity and pattern of electric potential were dependent on the ground connection condition and individual. Also, the electric potential pattern was very similar to the pattern of electric charge and discharge of capacitor. The acupuncture stimulation using a insulating needle resulted in lower average peak electric potential variation($0.25{\pm}0.16mV$) than that of acupuncture stimulation. It might present little electrical response of acupuncture stimulation using insulating needles. In point of electrical response, the laser stimulation was determined to be no acupuncture effect at meridian. Acupuncture stimulation seems to be most effective method to induce electrical response at meridians. The procedure and effect of acupuncture might be considered as energy consensus phenomenon by transportation of bio-ion charge between a practitioner and patient.

• Environmental and Resource Economics Review
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• v.30 no.2
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• pp.237-268
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• 2021

As variable renewable sources rapidly increase due to the Energy Transition plan, integration cost of renewable sources to the power system is rising sharply. The increase in variable renewable energy reduces the capacity factor of existing traditional power capacity, and this undermines the efficiency of the overall power supply, and demand resources are drawing attention as a solution. In this study, we analyzed how much electric vehicle demand resouces, which has great potential among other demand resources, can reduce power supply costs if it is used as a flexible resource for renewable generation. As a methodology, a stochastic form of power system optimization model that can effectively reflect the volatile characteristics of renewable generation is used to analyze the cost induced by renewable energy and the benefits offered by electric vehicle demand resources. The result shows that virtual power plant-based direct control method has higher benefits than the time-of-use tariff, and the higher the proportion of renewable energy is in the power system, the higher the benefits of electric vehicle demand resources are. The net benefit after considering commission fee for aggregators and battery wear-and-tear costs was estimated as 67% to 85% of monthly average fuel cost under virtual power plant with V2G capability, and this shows that a sufficient incentive for market participation can be offered when a rate system is applied in which these net benefits of demand resources are effectively distributed to consumers.

• Journal of the Korean Applied Science and Technology
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• v.38 no.3
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• pp.903-913
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• 2021

Three-type PVC membranes denoted by AEM-1, AEM-2, and AEM-3 with a cross-linked anion-exchange group were prepared by substitution reaction of PVC with triethyldiamine (TEDA), 1,4-dimethylpiperazine (DMP), and 1,4-bis(imidazol-1-ylmethyl)benzene (BIB) in cyclohexanone, respectively. We confirmed the successful preparation of the AEM-1, AEM-2, and AEM-3 via ionic conductivity (S/cm), water uptake (%), contact angle, ion-exchange capacity (m_eq/g), thermal properties, SEM and XPS analysis, respectively. The electrochemical capacitor experiments using PVC membrane with cross-linked anion-exchange group in organic electrolytes were performed. The prepared AEM-1, AEM-2 AEM-3 have a good stability by charge and discharge performance in organic electrolyte. As a result, the AEM-2 and AEM-3 membrane based on PVC prepared by the solvent casting method after substituent reaction is suitable for the use as a separator in organic electrochemical capacitor (supercapacitor).

• Journal of the Korea Convergence Society
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• v.13 no.4
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• pp.331-337
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• 2022

Manufactured thermoplastic composite materials to replace the metal materials used as battery housing materials for electric vehicles with lightweight materials. As the matrix material, nylon 6 which is a polymer material was used. Boron Nitrate(BN), which has high thermal conductivity, was used to provide heat dissipation performance. The heat dissipation characteristics of the thermally conductive polymer composite material according to the BN content and particle size were analyzed. The thermal conductivity value increased as the filler content increased, and composite materials particle size of 60 to 70㎛ and BN content of 50%, the thermal conductivity was 1.4 W/mK. The larger the particle size, the wider the inter-particle interface contact surface, which means that a thermal path was formed. wider the interfacial contact surface between the particles, and the thermal path was formed. A battery housing was manufactured using the manufactured thermally conductive polymer composite material, and the temperature change during charging and discharging of the cell was observed, and the possibility as a substitute material for the battery housing was confirmed.

• Journal of the Korean Electrochemical Society
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• v.26 no.3
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• pp.35-41
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• 2023

The carbon-coated silicon monoxide (c-SiO_x), which is a negative electrode active material for lithium-ion batteries (LIBs), has a limited cycle performance due to severe volume changes during cycles, despite its high specific capacity. In particular, the significant volume change of the active material can deform the electrode structure and easily damage the electron transfer pathway. To improve performance and mitigate electrode damage caused by volume changes, we replaced parts of the carbon black conducting agent with carbon nanotubes (CNTs) having a linear shape. The content of the entire conductive material in the electrode was fixed at 10% by mass, and the relative content of CNTs ranged from 0% to 25% by mass to prepare electrodes and evaluate electrochemical performance. As the CNT content in the electrode increased, both cycle life and rate capability improved. Even a small amount of CNT can significantly improve the electrochemical performance of a c-SiO_x negative electrode with large volume changes. Furthermore, dispersing CNTs effectively can lead to achieving the equivalent performance with a reduced quantity of CNTs.

• Journal of Internet of Things and Convergence
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• v.10 no.1
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• pp.1-6
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• 2024

In order to increase the use of electric vehicles (EVs) and minimize grid strain, microgrid using renewable energy must take an important role. Microgrid may use fossil fuels such as small diesel power, but in many cases, they can be supplied with energy from renewable energy, which is an eco-friendly energy source. However, renewable energy such as solar and wind power have variable output characteristics. Therefore, in order to meet the charging and discharging energy demands of electric vehicles and at the same time supply load power stably, it is necessary to review the configuration of electric vehicle charging infrastructure that utilizes diesel power or electric vehicle-to-grid (V2G) as a parallel energy source in the microgrid. Against this background, this study modelized a microgrid that can stably supply power to loads using solar power, wind power, diesel power, and V2G. The proposed microgrid uses solar power and wind power generation as the primary supply energy source to respond to power demand, and determines the operation type of the load's electric vehicles and the rotation speed of the load synchronous machine to provide stable power from diesel power for insufficient generations. In order to verify the system performance of the proposed model, we studied the stable operation plan of the microgrid by simulating it with MATLAB /Simulink.

• Journal of the Korean Electrochemical Society
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• v.16 no.2
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• pp.59-64
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• 2013

Using $Na_2CO_3$ and $MeSO_4$ (Me = Ni, Co and Mn) as starting materials, the precursor of $[Ni_{0.6}Co_{0.2}Mn_{0.2}]CO_3$ has been synthesized by carbonate co-precipitation. The precursor was mixed with $Li_2CO_3$, and calcined at 750, 850, and$950^{\circ}C$ in air. Effect of calcinations temperature on characteristics of $Li[Ni_{0.6}Co_{0.2}Mn_{0.2}]O_2$ cathode materials was investigated. The structure and characteristics of $Li[Ni_{0.6}Co_{0.2}Mn_{0.2}]O_2$ were determined by X-ray diffraction (XRD), Scanning electron microscopy (SEM) and electrochemical measurements. The X-ray diffraction (XRD) results show that the intensity ratio of $I_{(003)}/I_{(104)}$ increased and the R-factor ratio decreased with the increase of calcinations temperature. And Scanning electron microscopy (SEM) result show that the primary particle size increased. Especially, the $Li[Ni_{0.6}Co_{0.2}Mn_{0.2}]O_2$ calcined at $950^{\circ}C$ for 24 H shows excellent electrochemical performances with reversible specific capacity of $165.3mAhg^{-1}$ [cut-off voltage 2.5~4.3 V, 0.1 C($17mAhg^{-1}$)] and good capacity retention of 95.4% after 50th charge/discharge cycles[cut-off voltage 2.5~4.3 V, 1 C($170mAhg^{-1}$)].