• Transactions of the Korean hydrogen and new energy society
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• v.8 no.2
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• pp.51-56
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• 1997

The Zr-based Laves phase, $ZrV_2$ hydrogen storage alloy is not suited for the electrode of Ni-MH battery, because the binding strength of that with hydrogen is too strong although the storage capacity is high. For an application to electrode a part of V in alloys is substituted with Ni to make weaken the binding strength. The electrochemical and thermodynamic properties of Zr-V-Ni system alloys are investigated from the equilibrium potential and studied the possibility for the application to the rechargeable battery electrode.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.2
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• pp.45-49
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• 2006

Electrochemical hydrogenation/dehydrogenation properties were studied for a single particle of a Mm-based(Mm : minh metal) hydrogen storage alloy($MmNi_{3.55}Co_{0.75}Mn_{0.4}Al_{0.3}$) for fuel cell and Ni-MH batteries. A carbon fiber microelectrode was manipulated to make electrical contact with an alloy particle, and the potential-step experiment was carried out to determine the apparent chemical diffusion coefficient of hydrogen atom($D_{app}$) in the alloy. Since the alloy particle we used here was a dense, conductive sphere, the spherical diffusion model was employed for data analysis. $D_{app}$ was found to vary the order between $10^{-9}\;and\;10^{-10}[cm^2/s]$ over the course of hydrogenation and dehydrogenation process. Compared with the conventional composite film electrodes, the single particle measurements using the microelectrode gave more detailed, true information about the hydrogen storage alloy.

• Transactions of the Korean hydrogen and new energy society
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• v.13 no.2
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• pp.135-142
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• 2002

본 연구는 Chemical hydride 형태의 수소발생제를 포함한 액체연료를 이용한 신개념의 알칼라인 연료전지의 특성을 분석하였다. Chemical hydride는 연료전지의 수소공급원으로써 사용될 수 있으며, 본 연구팀은 KOH 전해질에 수소발생제인 Sodium Borohydride ($NaBH_4$)를 첨가하여 제조된 액체연료를 알칼라인 연료전지에 공급함으서 상온에서 매운 우수한 전기 화학적 성능결과를 얻을 수 있었다. 이때 음극 찰물질로 $ZrCr_{0.8}Ni_{1.2}$ 수소저장합금이 사용되었으며, 양극은 방수처리된 카본지 위에 분산된 Pt/C 가 사용되었고, air가 latm으로 양극에 공급되었다. 음극에 대한 XRD 분석결과 음극에서의 산화에 의해 Sodium Borohydride ($NaBH_4$)가 분해되어 수소가 발생되며, 연속적으로 액체연료가 주입되어도 전지가 작동하는 것을 확인할 수 있었다. 이때 에너지밀도는 6,000 Ah/kg (for $NaBH_4$ or $KBH_4$)이다.

• Korean Chemical Engineering Research
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• v.43 no.4
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• pp.439-451
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• 2005

This article provides a panoramic overview of the state-of-the-art technologies in the field of solid-state hydrogen storage methods. The emerging solid-state hydrogen storage techniques, such as nanostructured carbon materials, metal organic framework (MOFs), metal and inter-metal hydrides, clathrate hydrates, complex chemical hydride are discussed. The hydrogen storage capacity of the solid-sate hydrogen storage materials increases in proportion to the surface area of the solid materials. Also, it is believed that new functional nanostructured materials will offer far-reaching solutions to the development of on-board hydrogen storage system for the application of the transportation vehicles.

• Applied Chemistry for Engineering
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• v.18 no.2
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• pp.99-110
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• 2007

Efficient and inexpensive hydrogen storage is an essential prerequisite for the utilization of hydrogen, one of the new and clean energy sources for $21^{st}$ century. In this review, several storage techniques are briefly reviewed and compared. Especially, adsorption/storage via physisorption at low temperature, by using nanoporous adsorbents, is reviewed and evaluated for further developments. The adsorption over a porous material at low temperature is currently investigated deeply to fulfill the storage target. In this review, several characteristics needed for the high hydrogen adsorption capacity are introduced. It may be summarized that following characteristics are necessary for high storage capacity over porous materials: i) high surface area and micropore volume, ii) narrow pore size, iii) strong electrostatic field, and iv) coordinatively unsaturated sites, etc. Moreover, typical results demonstrating high storage capacity over nanoporous materials are summarized. Storage capacity up to 7.5 wt% at liquid nitrogen temperature and 80 atm is reported. Competitive adsorbents that are suitable for hydrogen storage may be developed via intensive and continuous studies on design, synthesis, manufacturing and modification of nanoporous materials.

• Journal of the Korean Electrochemical Society
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• v.11 no.4
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• pp.289-296
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• 2008

Electrochemical studies were performed by a half-cell test for the nickel hydroxide (cathode) and hydrogen storage alloy(anode) electrodes for the sealed Ni-MH batteries applicable to industrial use. The electrodes were fabricated and checked a charge efficiency and an internal pressure of the battery during charge-discharge cycling. In order to reduce the internal pressure of the sealed Ni-MH battery, cyclic voltammetry (CV) were performed on the electrodes of nickel hydroxide(cathode) and hydrogen storage alloy(anode), respectively. The results of the test showed clearly the oxidation/reduction and oxygen evolution reaction in a nickel hydroxide electrode and the hydrogenation behavior of a hydrogen storage electrode. The sealed Ni-MH battery of 130Ah was fabricated by using nickel hydroxide of a high over-voltage for an oxygen gas evolution and hydrogen storage alloy of a good performance for activation The battery showed a good characteristics such as a high charge efficiency of 98% at 1 C charge current, a low level internal pressure of 4 atm on a continuous over-charging and a large preservation capacity of 95% at 400 cycle.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.6
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• pp.69-74
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• 2006

The effects of mechanical grinding(MG) treatment on the hydrogen storage of $Mg_2Ni$ alloy and $Mg_2Ni$ composite alloy($Mg_2Ni+graphite$) were investigated by pressure-composition-temperature(PCT) measurement, the micro-electrode technique of electrochemistry and etc, in which PCT was measured at high temperature(around $300[^{\circ}C]$) of gas phase and a carbon-filament micro-electrode for electrochemical evaluation was manipulated to make electrical contact with the particle in 1M KOH aqueous solution. It was found that the hydrogenation properties of $Mg_2Ni$ and graphite composite particle were greatly improved by the mechanical grinding treatment by which the $Mg_2Ni$ and graphite composite alloys could be changed into microstructure and nano-level particles. namely; the hydrogen dissociation pressure of PCT measurement was decreased from 0.55[MPa] to 0.42[MPa] and hydrogenation peaks by micro-electrode were also observed more clearly on the same sample.

• Journal of the Korean Institute of Gas
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• v.28 no.2
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• pp.7-16
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• 2024

This study presents investigation on the technical characteristics and field cases of the salt cavern storage method for large-scale hydrogen storage. The salt cavern storage method enables effective hydrogen storage compared to other methods due to the low porosity and permeability of the rock salt that constitutes the cavern, which is not likely to leak and requires a small amount of cushion gas for operation. In addition, there is no chemical reaction between rock salt and hydrogen, and multiple injection/withdrawl cycles can be performed making it effective for peak shaving and short-term storage. The salt cavern is formed in three stages: leaching, debrining, and filling, and leakage tests are conducted to ensure stable operation. Field applications are currently performing to meet industrial demand in the surrounding area of four sites in the UK and Texas, USA, and salt cavern operation is being prepared for energy storage in European countries such as Germany and France. The investigated results in this study can be utilized as a basic guideline for the design of future hydrogen storage projects.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.558-559
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• 2008

본 논문은 미 일리노이 주립대 어바나-샴페인 캠퍼스에서 주로 군사용 응용 관련하여 개발 중인 마이크로 PEM 연료전지 시스템 개발에 대한 논문이다. 본 연구는 수소 저장 장치까지 포함하여 1 $mm^3$의 초소형 연료전지 시스템을 목표로 진행 중이며 본 논문은 이러한 진행 과정 중 화학적 하이드라이드 기반의 수소 발생기와 10 $mm^3$의 시스템 개발 과정에 대해 보고한다.

• Applied Chemistry for Engineering
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• v.20 no.5
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• pp.465-472
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• 2009

The technologies for improving the capacity of hydrogen storage were investigated and the recent data of hydrogen storage by using various porous carbon materials were summarized. As the media of hydrogen storage, activated carbon, carbon nanotube, expanded graphite and activated carbon fiber were mainly investigated. The hydrogen storage in the carbon materials increased with controlled pore size about 0.6~0.7 nm. In case of catalyst, transition metal and their metal oxide were mainly applied on the surface of carbon materials by doping. Activated carbon is relatively cheap because of its production on a large scale. Carbon nanotube has a space inside and outside of tube for hydrogen storage. In case of graphite, the distance between layers can be extended by intercalation of alkali metals providing the space for hydrogen adsorption. Activated carbon fiber has the high specific surface area and micro pore volume which are useful for hydrogen storage. Above consideration of research, porous carbon materials still can be one of the promising materials for reaching the DOE target of hydrogen storage.