• Title/Summary/Keyword: Metal hydride

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Material Life Cycle Assessment on Mg2NiHx-CaF2 Composites (Mg2NiHx-CaF2 수소 저장 복합체의 물질 전과정 평가)

  • HWANG, JUNE-HYEON;SHIN, HYO-WON;HONG, TAE-WHAN
    • Transactions of the Korean hydrogen and new energy society
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    • v.33 no.2
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    • pp.148-157
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    • 2022
  • Research on hydrogen storage is active to properly deal with hydrogen, which is considered a next-generation energy medium. In particular, research on metal hydride with excellent safety and energy efficiency has attracted attention, and among them, magnesium-based hydrogen storage alloys have been studied for a long time due to their high storage density, low cost, and abundance. However, Mg-based alloys require high temperature conditions due to strong binding enthalpy, and have many difficulties due to slow hydrogenation kinetics and reduction in hydrogen storage capacity due to oxidation, and various strategies have been proposed for this. This research manufactured Mg2Ni to improve hydrogenation kinetics and synthesize about 5, 10, 20 wt% of CaF2 as a catalyst for controlling oxidation. Mg2NiHx-CaF2 produced by hydrogen induced mechanical alloying analyzed hydrogenation kinetics through an automatic PCT measurement system under conditions of 423 K, 523 K, and 623 K. In addition, material life cycle assessment was conducted through Gabi software and CML 2001 and Eco-Indicator 99' methodology, and the environmental impact characteristics of the manufacturing process of the composites were analyzed. In conclusion, it was found that the effects of resource depletion (ARD) and fossil fuels had a higher burden than other impact categories.

Activation Characteristics of Metal Hydride Chemical-Treated and Fixed in an Adhesive (화성처리 및 성형화에 따른 금속수소화물의 활성화거동)

  • Han, H.K.;Park, C.K.
    • Transactions of the Korean hydrogen and new energy society
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    • v.6 no.2
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    • pp.85-90
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    • 1995
  • Activation behavior, hydriding rate and disintegration were tested for hydrogen storage alloy particles fixed in an adhesive after treating with inorganic solution. Commertial adhesive as a binder was used. Chemical-treated particles showed the best characteristics for activation and a little effect of prevention the break down of the powders themselves after several repeated operations. Furthermore activation characteristics were found to show a similar trend to chemical-treated powders even in the fixed one with an adhesive, except for a slight decrease in reaction velocity.

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Preparation of Thin Nickel Foam for Nickel-Metal Hydride Battery (Ni-MH 전지용 thin nickel foam의 제조)

  • 신준호;김기원
    • Journal of the Korean institute of surface engineering
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    • v.28 no.2
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    • pp.83-91
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    • 1995
  • A new method for preparation of thin nickel foam for Ni-MH battery was investigated. In this method, fine graphite powders of $1\mu\textrm{m}$$2\mu\textrm{m}$ diameter were pasted into pores of thin polyurethane foam film in order to supply electric conducting seeds for nickel deposition by electroless plating reaction. After electroless plating, remaining polyurethane foam was removed chemically by organic solvent treatment and graphite particles also removed by ultrasonic cleaning. Porosity of formed nickel foam was about 85% During electroplating, porosity of the nickel foam decreased less than 5% up to $30\mu\textrm{m}$ coating thickness. And then it was electroplated and heat-treated to improve mechanical strength and ductility. Finally, thin nickel foam for Ni electrode of Ni-MH battery with 80% porosity and $350\mu\textrm{m}$~X$400\mu\textrm{m}$ thickness was obtained.

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A Study on the Cycle Life Improvement of V-Ti-Ni(V-rich) Alloy as a Negative Electrode for Ni/MH Rechargeable Battery (Ni/MH 2차전지의 음극으로써 V-Ti-Ni(V-rich) 수소저장합금의 전극수명 향상에 관한 연구)

  • Kim, Ju-Wan;Lee, Seong-Man;Lee, Jae-Yeong
    • Transactions of the Korean hydrogen and new energy society
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    • v.7 no.1
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    • pp.39-44
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    • 1996
  • The discharge capacity of V-Ti-Ni(V-rich) metal hydride electrode during the charge-discharge cycling was investigated in KOH electrolyte. All electrodes were degraded within 25 cycles. To investigate the cause of the degradation phenomena impedance measurements were performed by using E.I.S(electrochemical impedance spectroscopy). The surfaces of the degraded electrodes were examined by Auger electron spectroscopy (AES). It was observed that all electrodes were covered with oxygen from the surface to the bulk, titanium was enriched near surface, and vanadium was dissolved from the surface to the bulk.

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Equilibrium and Hydriding Characteristics of Metal Hydride Chemical-Treated and Compacted in Pellet (화성처리 및 성형화에 따른 금속수소화물의 평형특성 및 수소흡장거동)

  • Park, C.K.;Cho, T.H.
    • Transactions of the Korean hydrogen and new energy society
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    • v.5 no.1
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    • pp.9-17
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    • 1994
  • Activation behavior, hydriding rate and disintegration were studied for a compact in pellet form and hydrogen storage alloy particles treated with newly developed inorganic solution. Cylindrical disc of 12.95mm diameter and of 7.1mm thickness was prepared by compressing(8ton) a mixture of $MmNi_{4.5}Al_{0.47}$ and PTFE. Chemical treatment of particles with 1mol of solution was performed at room temperature for several hours until the pH of solution did not change. Chemical treatment made much accelerated activation without any incubation period which generally exists in the untreated alloys and the hydriding reaction rate after full activation also was improved.

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New Ball-Milled Metal Hydride Electrode for Rechargeable Batteries

  • Noh, Hak;Strom-Olsen, J.O.;Park, C.N.
    • Transactions of the Korean hydrogen and new energy society
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    • v.8 no.1
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    • pp.43-47
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    • 1997
  • A new type of anode materials in form of nanocrystalline composite powders has been developed that offers the potential for dramatically improved discharge capacity and initial activation rate. The composites are synthesized by ball milling of two components - a major component (basic component) having high hydrogen capacity and a minor component (surface activator) with good electrocatalytic activity. The capacity increase observed by ball milling with surface activator. The ball-milled composite materials are easier to activate than the non ball-milled basic component.

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Performance of a direct methanol fuel cell (DMFCs)Using Nation 115 (Nafion 115를 사용한 DMFC MEA 의 성능실험)

  • Choi, Hoon;Hwang, Yong-Sheen;Cha, Suk-Won
    • 한국신재생에너지학회:학술대회논문집
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    • 2007.11a
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    • pp.43-46
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    • 2007
  • To find out the optimum design of hydrogen storage and supply tank using Metal Hydride (briefly MH) and to make clear the performance characteristics under various conditions are our research purpose. In order to use the low-temperature exhaust heat, $LaNi_{4.7}Al_{0.3}$ which operates under the low pressure of 1MPa is chosen, and we measure the basic properties, namely density, specific heat, PCT(Pressure-Concentration-Temperature) characteristic, and effective thermal conductivity. Then, a numerical calculation model of hydrogen storage using MH alloy is suggested and this thermal diffusion equation of model is solved by the backward difference method. This calculation results rate compared with the experimental results of the systems which installed 1kg MH alloy and, it is found out that our calculation model can well predict the experimental results. By the experimental using MH alloy, it is recognized that the hydrogen flow rate can control by the step adjustment of brine temperature.

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Heat and Mass Transfer Properties of Mm-Based Metal Hydride upon Co Content (Mm계 금속수소화물의 Co함량에 따른 열 및 물질전달특성)

  • Park, Chan-kyo
    • Transactions of the Korean hydrogen and new energy society
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    • v.15 no.2
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    • pp.144-151
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    • 2004
  • The effect of the cobalt content on the thermodynamic and, heat and mass transfer properties of the $MmNi_{5-y}B_{y-z}C_z(y=0.5{\sim}1.5,\;z=0.5)$hydrogen storage alloys has been studied systematically. The P-C isotherms curves show that with increasing cobalt content in the alloys, the plateau pressure of the hydrogen absorption and desorption and enthalpy(${\Delta}H$) increases steeply and the plateau region becomes flat, while entropy(${\Delta}S$) decreases. Also at the constant cobalt content the hydrogen transfer rate decreases with the reaction temperature, while the initial reaction kinetics increases. But the initial reaction with hydrogen completes within 1min, although the reaction proceeds about 30minutes thereafter.

Railway system standby power Nickel metal hydride battery (철도시스템비상전원용 니켈수소(NiMH)전지)

  • Park, Dong-Pil
    • Proceedings of the KSR Conference
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    • 2006.11b
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    • pp.636-645
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    • 2006
  • In order to use railway system standby power, produced 160Ah NiMH battery that would be able to substitute the lead acid battery or NiCd battery form which contain the toxic material in environment, using parallel connected 80Ah NiMH battery. And in order to develop proper electrode in the 160Ah NiMH battery, tested high rate discharge performance of the ternary electrolyte. 160Ah NiMH battery evaluated the various test in order to use railway system standby power.

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Addition Compounds of Alkali Metal Hydrides. 32. A Comparison Study of Chiral Trialkylborohydrides and Chiral Dialkylmonoalkoxyborohydrides for the Asymmetric Reduction of Prochiral Ketones: The Effect of Comparable Chiral Alkyl and Alkoxy Groups on Asymmetric Industion$^\dag$

  • Brow, Hervert C.;Park, Won-Suh;Cho, Byung-Tae
    • Bulletin of the Korean Chemical Society
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    • v.8 no.4
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    • pp.276-280
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    • 1987
  • Several chiral potassium B-alkyl-9-boratabicyclo[3.3.1]nonanes $(K\; B-R^*-9-BBNH)$ and potassium B-alkoxy-9-boratabicyclo[3.3.1]nonanes $(K \;B-OR^*-9-BBNH)$ were synthesized by treatment of the corresponding trialkylboranes and dialkylmonoalkoxyboranes with a small excess of potassium hydride. The chiral B-alkoxy derivatives generally reduce representative ketones, such as acetophenone and 3-methyl-2-butanone, with greater optical induction than the corresponding B-alkyl derivatives, suggesting the involvement of the oxygen atom in the control process for asymmetric synthesis.