TAKESHITA, Hiroyuki | pseudonym etc:TAKESHITA, T. Hiroyuki |
|---|
Faculty, Department/Institute
- Faculty of Chemistry, Materials and Bioengineering Department of Chemistry and Materials Engineering
Academic status (qualification)
- Professor Apr. 1,2011
Undergraduate Degrees・University
- Kyoto University Faculty of Engineering1989 Graduated
Graduate Degrees・University
- Kyoto University Doctor's Degree Program 1995 Completed
Academic Degrees
- Doctor of Engineering Mar. 1995 Kyoto University
Homepage Address, E-mail Address
- Homepage Address：http://www.kumse.kansai-u.ac.jp/
Research fields
| Research fields | keyword |
|---|---|
| Hydrogen storage materials |
Research topics
| research topic | Study for improvement of reaction rate of inorganic complex hydrides by forming fluid state |
|---|---|
| Study theme state | |
| research duration | |
| Research Programs | |
| keyword | inorganic-complex-hydrides,catalyst,melting point,dehydrogenation, |
| Research field | |
| Research Topics Overview |
| research topic | Research and developement of Ca-based hydrogen storage materials |
|---|---|
| Study theme state | |
| research duration | 2002 ～ 2005 |
| Research Programs | |
| keyword | hydrogen storage materials,Ca-based alloys,phase transformation, |
| Research field | |
| Research Topics Overview |
| research topic | Hydrogenation properties and corresponding phase transformation of A7B10 type intermetallic compounds |
|---|---|
| Study theme state | |
| research duration | |
| Research Programs | |
| keyword | metal hydrides,hydrogen storage materials,phase transformation, |
| Research field | |
| Research Topics Overview |
Research Activities
- My research subjects have been the developement of new alloys and hydrides for hydrogen storage and the studies about their hydrogenation properteis at equilibrium state and the corresponding phase transformation.
Research Career
- National Institute of Advanced Industrial Science and Technology (Osaka National Research Institute), Senior Research Scientist 1995/4/1～2002年/3/31
Awards
- Best poster award Aug. 26,1996(Committee of MH symposium)
- Student Award Nov. 8,1993(Committee of symposium of SIMS-IX)
Academic Associations
| 所属学会・団体名 | 役職名 (役職在任期間) |
|---|---|
| The Japan Institute of Metals |
Topics for Business-Government-Universities Joint Reserch
- Hydrogenation properties of martensitic TiNi-based alloys
Joint Projects/Commissioned Projects
- Study on Ca-based hydrogen storage alloys
2002 - 2004 From contract research companies - Basic research on combined interstitial-complex hydrides
2002 - 2003 From contract research companies - Study for improvement of reaction rate of inorganic complex hydrides by forming fluid state
2003 - 2005 From contract research companies - Research of new X-TM-Y alloys (X=Ca, Mg, Li; TM=transition metals; Y=metals)
2002 - 2006 International Joint Research
2003 - 2005 Joint Research on campus
2005 - 2007 Joint Research on campus
Research Publications
Chapter or SectionDevelopement of Hydrogen Storage Materials and its ApplicationsUnrefereedMonographCo-authored chapterTAKESHITA, Hiroyuki T.Hydrogen storage alloys;Magnesium hydride;Super laminate composite;Stationary hydrogen storage2016/4/8～
PapersFormation of MgCu2 from MgH2 and Cu in Pressurized Hydrogen AtmosphereIn refereedAcademic JournalCo-authorSHIBATA Kazuya;TANAKA Koji;KURUMATANI Kosuke;NISHIDA Yasuki;KONDO Ryota;TAKESHITA, Hiroyuki T.;accumulative rolling;super laminate composite;magnesium hydride;copper;MgCu2;dehydrogenation;Materials TransactionsVol. 56, No. 6, pp. 785-7892015/5/25～We have been proposing that there are competitive two kinds of pathways in the hydrogenation of Mg/Cu super-laminate composites. The one is that Mg reacts with Cu to form Mg2Cu and then Mg2Cu is hydrogenated to form MgH2 and MgCu2. The other is that Mg is hydrogenated and then MgH2 and Cu reacts to form MgCu2 together with H2 gas, according to a hypothesis that the reaction of MgH2 + 2Cu → MgCu2 + H2 occurs. In the present study, the reaction conditions such as pressure and temperature were investigated in order to confirm that the hypothesis is true. Well-mixed MgH2 and Cu powder was compressed to a pellet at 1.73 GPa and then heated at various hydrogen pressures and temperatures. Following results were obtained from the experiments at 673 K. The above-mentioned alloying accompanied by H2 emission occurs at pressures higher than 6.6MPa of H2 pressure, which is higher than lower limit for the hydrogenation of Mg2Cu. On the other hand, Mg2Cu is formed at 3.3 MPa which is lower than the limit. The reaction of MgH2 with Cu also occurs at 573K in 3.3 MPa H2. But it requires very long time such as 691.2 ks, although the existence of MgCu2 is confirmed in 86.1 ks of heating time in the case of Mg/Cu super-laminate composites.
International academic conferenceLong cycle-life organic electrode material based on an ionic naphthoquinone derivative for rechargeable batteriesIn refereedAcademic JournalCo-authorMasaru Yao;Tatsuhiro Numoto;Miho Araki;Hisanori Ando;Hiroyuki T. Takeshit;Tetsu Kiyobayashi;Cycle-stability;DFT calculation;Lithium ion battery;Organic cathode material;Two-electron redox;Energy Procediavol. 56, pp. 228 – 2362014/9～11th Eco-Energy and Materials Science and Engineering (11th EMSES)The applicability of the redox reactions of 5,8-dihydroxy-1,4-naphthoquinone (1) and its lithium salt, 5,8-dihydroxy-1,4-naphthoquinone dilithium salt (2), as positive electrode active materials for rechargeable lithium batteries was investigated. The
prepared electrodes showed initial discharge capacities of 170 mAh g(1)-1 with an average voltage of 2.2 V vs. Li+/Li, and 247 mAh g(2)-1 with an average voltage of 2.1 V vs. Li+/Li for 1 and 2, respectively. The obtained discharge capacities correspond to their two-electron redox behaviors. While the electrode using 1 suffered from a poor cycle-stability, the one using 2 underwent many cycles; i.e., after a small drop in the capacity at the first cycle, the capacity of the latter electrode hardly decayed during the subsequent 100 cycles. The effects of the introduction of ionic groups on the physical properties including the cycle stability were discussed along with quantum chemistry calculation results.
PapersHydrogen Absorption and Desorption Behavior of Magnesium Hydride: Incubation Period and Reaction MechanismIn refereedAcademic JournalCo-authorTAKEICHI Nobuhiko;SAKAIDA Yasuhiro;KIYOBAYASHI Tetsu;TAKESHITA,Hiroyuki T.;magnesium;hydrogen desorption property;Kolmogolov-Johnson-Mehl-Avrami equation;Materials TransactionsVol. 55, No. 8, pp. 1161-11672014/5/30～The hydrogen absorption and desorption reactions of pure MgH2 were investigated by pressure-time measurements using a Sieverts’ type instrument in the temperature and pressure ranges of 653-683K and 0.5-1.7 MPa, respectively. The absorption and desorption behaviors were analyzed using a fraction of the reaction product during the hydrogen absorption and desorption. The fraction was evaluated based on the amount of absorbed and desorbed hydrogen.
The hydrogen absorption of pure Mg immediately occurs when the thermodynamic condition in which the reaction can proceed is reached at 653-683 K, but the hydrogen desorption does not start immediately when it can thermodynamically proceed at the same temperatures. Incubation periods were observed and had varied values in the range from 0.15 to 1.5 ks under the above-mentioned pressure and temperature conditions.
In order to clarify the hydrogen desorption mechanism, the data obtained were analyzed by the Kolmogorov-Johnson-Mehl-Avrami (KJMA) equation. The obtained values of the Avrami exponents varied from 3 to 0.6 with the increasing fraction of Mg. The hydrogen desorption process was classified into four stages based on the KJMA plots of the hydrogen desorption curves of MgH2 measured in this study.
These values indicated that the Mg nuclei generate and three-dimensional grow during the initial stage, then the growth is restricted to a two- or one-dimensional.
PapersMicro/Nano-Structural Transition and Hydrogen Absorption Mechanism in Mg/Cu Super-Laminate CompositesIn refereedAcademic JournalCo-authorTANAKA Koji;TAKESHITA,Hiroyuki T.;SHIN Ho;KURUMATANI Kosuke;KIYOBAYASHI Tetsu;TAKEICHI Nobuhiko;MIYAMURA Hiroshi;KIKUCHI Shiomi;super-laminate composite;micro/nano-structural transition;hydrogen absorption/desorption;differential scanning calorimetry;hydrogen absorption mechanism;scanning electron microscope;scanning transmission electron microscope;Materials TransactionsVol. 55, No. 8, pp. 1122-11282014/5/16～The micro/nano-structural transition and hydrogen absorption mechanism in Mg/Cu super-laminate composites (SLCs) were investigated. Differential scanning calorimetry (DSC) measurements were performed on Mg/Cu SLCs at several heating rate and till several repetition cycles up to twenty cycles, and micro/nano-structures of Mg/Cu SLCs were examined by stereomicroscope, digital-microscope, scanning electron microscope (SEM), and scanning transmission electron microscope (STEM). It is found that the micro/nano-stractures of Mg/Cu SLCs change drastically at early cycles and reach a steady state after around the tenth cycle. The detailed examination of DSC curves, and SEM and STEM
observations of Mg/Cu SLCs suggest that the hydrogen absorption process consists of a fast and a slow reaction which shows a sharp exothermic peak around at 610K and a broad exothermic peak around at 570K connected with it in DSC profiles, respectively.
Academic presentationIKEUCHI Syu-u-ki;SHIBATA Kazuya;TANAKA Koji;KONDO Ryota;TAKESHITA,Hiroyuki T.;2014/3/22～
Academic presentationKONDO Ryota;MIYAZAKI Yuhei;TAKESHITA Hiroyuki T.;2014/3/22～
Academic presentationSATAKE Syunsuke;ODAGAKI Kensuke;KONDO Ryota;TAKESHITA,Hiroyuki T.;TANAKA Koji;2014/3/22～
International academic conferenceLong cycle-life organic electrode material based on an ionic naphthoquinone derivative for rechargeable batteriesUnrefereedAcademic JournalCo-authorYAO Masaru;NUMOTO Tatsuhiro;ARAKI Miho;ANDO Hisanori;TAKESHITA,Hiroyuki T.;KIYOBAYASHI Tetsu;Cycle-stability;DFT calculation;Lithium ion battery;Organic cathode material;Two-electron redox;Energy ProcediaVol. 56, pp. 228-2362013/12/18～2013/12/2111th Eco-Energy and Materials Science and Engineering (11th EMSES)Phuket, THAILANDThe applicability of the redox reactions of 5,8-dihydroxy-1,4-naphthoquinone (1) and its lithium salt, 5,8-dihydroxy-1,4-naphthoquinone dilithium salt (2), as positive electrode active materials for rechargeable lithium batteries was investigated. The
prepared electrodes showed initial discharge capacities of 170 mAh g(1) -1 with an average voltage of 2.2 V vs. Li+/Li, and 247 mAh g(2) -1 with an average voltage of 2.1 V vs. Li+/Li for 1 and 2, respectively. The obtained discharge capacities
correspond to their two-electron redox behaviors. While the electrode using 1 suffered from a poor cycle-stability, the one using 2 underwent many cycles; i.e., after a small drop in the capacity at the first cycle, the capacity of the latter electrode hardly decayed during the subsequent 100 cycles. The effects of the introduction of ionic groups on the physical properties including the cycle stability were discussed along with quantum chemistry calculation results.
PapersThe effect of initial structures of Mg/Cu super-laminates on hydrogen absorption/desorption propertiesIn refereedAcademic JournalCo-authorKoji Tanaka;Hiroyuki T.Takeshita;Kosuke Kurumatani;Hiroshi Miyamura;Shiomi Kikuchi;Hydrogen absorption/desorption properties;Initial structures;Super-laminates;Magnesium;Copper;Journal of Alloys and Compoundsvol. 580 (2013) S222-S2252013/12/15～The effect of initial structures of Mg/Cu super-laminates on hydrogen absorption/desorption properties was investigated experimentally. Mg/Cu super-laminates were prepared by a repetitive fold and roll method using a conventional two-high roll mill. Three types of specimens were prepared by changing rolling reduction in cold rolling. Each of them had a fine, medium, coarse microstructure, respectively. Hydrogen absorption/desorption properties were measured with HP-DSC and a Sieverts’ type instrument. Microstructures were observed with SEM. Two types of MgCu2 forms, 3D-network and layered forms, were observed after hydrogenation under the conditions of 573 K, 86.4 ks and 3.3 MPa of H2, respectively. This implies that Mg/Cu super-laminates can be hydrogenated by two kinds of processes. The dominant process depends on the initial structures of Mg/Cu super-laminates. Repetitive hydrogenation/dehydrogenation tests using HP-DSC indicate that, even after 20 cycles, the initial microstructures of Mg/Cu super-laminates can affect their hydrogen absorption/desorption properties.
PapersHydrogenation Properties of MgCu2: Mechanism of Formation of MgCu2 in Hydrogenation of Mg/Cu Super-Laminate CompositesIn refereedAcademic JournalCo-authorKazuya Shibata;Koji Tanaka;Kosuke Kurumatani;Ryota Kondo;Hiroyuki T. Takeshita;MgCu2;super-laminate composite;microstructure;hydrogenation;van't Hoff plot;Journal of Japan Institute of Metals and MaterialsVol. 77, No.12, 631-6352013/12/1～10.2320/jinstmet.JC201308We proposed that there are two kinds of competitive processes in the hydrogenation of Mg/Cu super-laminate composites; the one in which alloying (formation of MgCu2 fromMg and Cu) occurs in advance and Mg2Cu is hydrogenated to form MgH2 and MgCu2, and the other in which Mg is hydrogenated and then MgH2 and Cu react to formMgCu2 together with H2 gas, according to a hypothesis that the reaction of MgH2＋2Cu→MgCu2＋H2 occurs. In order to confirm that the hypothesis is true, we investigated the conditions such as H2 pressure and temperature at which the above-mentioned reaction proceeds. Well-mixed MgH2 and Cu powder was compacted to form pellet at 1.73 GPa and then heated at various hydrogen pressures and temperatures. Experimental results at 673 K indicated that the above-mentioned reaction occurs at pressures higher than 6.5 MPa, approximately the lower limit for the hydrogenation of Mg2Cu, whereas both Mg2Cu and MgCu2 are formed at 3.3 MPa.
PapersConductivity, viscosity and density of MClO4 (M = Li and Na) dissolved in propylene carbonate and γ-butyrolactone at high concentrationsIn refereedAcademic JournalCo-authorKURATANI Kentarou;UEMURA Naoya;SENOH Hiroshi;TAKESHITA,Hiroyuki T.;KIYOBAYASHI Tetsu;High concentration electrolyte;Nonaqueous;Cubic root law;Debye-Huckel-Onsagar theory;Pseudolattice model;Journal of Power SourcesVol. 223, pp. 175-1822013/2/1～The solution density, viscosity and conductivity of MClO4 (M = Li and Na) solutions in propylene carbonate and γ-butyrolactone are measured at the concentrations of <1.5-2.0 mol dm-3. The partial volume of the solute, derived from the density, of NaClO4 is greater than that of LiClO4 as expected. NaClO4 produces less viscous and more conductive solutions than LiClO4 throughout the examined concentration range. Notably, the conductivity of the NaClO4 solutions is 10-20% higher than that of the LiClO4 solutions at T/K = 298. The validity of the empirical cubic root law, Λ(C) = Λ0 － AC1/3, is examined, where Λ and Λ0 are the molar conductivities at the molarity C and at infinite dilution. The meaning of the slope A is interpreted in the theoretical framework of the pseudolattice model.
International academic conferenceCo-authorKoji TANAKA;Kosuke KURUMATANI;Hiroyuki T. TAKESHITA;Hiroshi MIYAMURA;Shiomi KIKUCHI;2012/10/21～2012/10/26
International academic conferenceCo-authorHiroyuki NAGAI;Youhei ITO;Hiroyuki T. TAKESHITA;2012/10/21～2012/10/26
International academic conferenceCo-authorKento Ishizuka;Toyokazu Eguchi;Hiroyuki T. Takeshita;2012/10/21～2012/10/26
PapersThermodynamic Property Change in LiNH Hydrogen Storage System by Melting Lithium AmideIn refereedAcademic JournalCo-authorTAKESHITA,Hiroyuki;;;2011/2/1～In this study, we used the Sieverts' method to measure the hydrogen pressure-composition isotherms of LiH and LiNH2 mixed in a molar ratio of 2:1 in order to obtain the standard reaction enthalpy and entropy of the hydrogenation reaction. The amounts of hydrogen absorbed and desorbed by the mixture were equal to the theoretical value at temperatures ranging from 653 K to 873K (which were higher than the melting temperature of the mixture), where the standard reaction enthalpy and entropy were －32±3 kJ･(mol H2)－1 and －68±4 J･K－1･(mol H2)－1, respectively. On the other hand, the amounts were less than the theoretical value at 553 K and 623 K (which were lower than the melting temperature) due to the incomplete reaction, indicating that these isotherms would not afford reliable estimates of the standard reaction enthalpy and entropy. Hence, we instead calculated the standard enthalpy and entropy below the melting temperature using the values above the melting temperature and the standard enthalpy and entropy of fusion of the mixture. The values thus obtained, －49±3 kJ･(mol H2)－1 and －95±5 J･K－1･(mol H2)－1, respectively, are significantly different from those previously reported. Here, the differences are discussed from the standpoint of the difficulty in measuring the hydrogen pressure-composition isotherms at lower temperatures as well as the validity of the method.
PapersPromotional Effect of Aluminum on MgH2+LiBH4 Hydrogen Storage MaterialsIn refereedAcademic JournalCo-authorYoung Li;Toshihisa Izuhara;Hiroyuki T. Takeshita;complex hydride;magnesium hydride;aluminum;reversibility;Materials Transactions52, (4), pp. 641-6462011/1/13～The effect of Al addition on the reversibility of a MgH2+2LiBH4 hydrogen storage mixture was examined in order to improve the mixture’s requirement for a hydrogen atmosphere even in dehydrogenation. The experiments using high pressure differential scanning calorimetry and X-ray powder diffraction confirmed that a MgH2+Al+4LiBH4 mixture can reversibly dehydrogenate and rehydrogenate below 773K under mild conditions of 0.1 MPa H2 for dehydrogenation and 4.0 MPa H2 for rehydrogenation. Moreover, thermogravimetry tests revealed that this mixture starts hydrogen desorption at about 530 K, which is 80K lower than the corresponding temperature for the MgH2+2LiBH4 mixture, and desorbs 9.5 mass% of hydrogen below 773 K. Thus, the addition of Al improves not only the reversibility of the reaction but also dehydrogenation kinetics. The hydrogen desorption of the mixture occurs by three steps, which includes the formation of Mg-Al alloys by the reaction of MgH2 and metallic Al followed by the formation of Mg1-xAlxB2 by the reaction of the Mg-Al alloys and LiBH4. Al in this mixture suppresses the formation of metallic Mg and accelerates the formation of Mg1-xAlxB2 from B produced by dehydrogenation of LiBH4. Mg1-xAlxB2 is derived from partial substitution of Al for Mg in MgB2, which contributes to reversible hydrogenation and dehydrogenation of MgH2+2LiBH4.
PapersIn refereedAcademic JournalCo-authorKazutaka Ikeda;Noriki Okuda ;Kenji Ohoyama;Hai-Wen Li;Hiroyuki T. Takeshita;Toshiya Otomo;Shin-ichi Orimo;2010/10/6～
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PapersIn refereedAcademic JournalCo-authorShou Takeuchi;Hiroshi Senoh;Shu Zhang;Hiroyuki T. Takeshita;Tetsu Kiyobayashi;Qiang Xu;Nobuhiro Kuriyama;2009/1/15～
Thermodynamic properties at the high temperature of the Li-N-H hydrogen storage systemCo-authorT. H. Izuhara;H. T. Takeshita;K. Kobayashi;2008/12/1～2008/12/42008 MRS Fall MeetingBoston, MA, USA
PapersEffect of Ball-Milling on the Properties of Mg2Cu Hydrogen Storage AlloyCo-authorM. X. Tanaka;N. Takeichi;H. T. Takeshita;T. Kiyobayashi;Mater. Trans49 (11), 2698-27012008/11～
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Effect of LiH amount on constituent phase and thermodynamics in Li-N-H hydrogen storage systemCo-authorT. H. Izuhara;K. Kobayashi;A. Miwa;H. T. Takeshita;2008/6/24～2008/6/28MH2008 International Symposium on Metal-Hydrogen SystemsReykjavik, Iceland
Theoretical and Experimental Consideration for Thermodynamic and Kinetic Improvement of De/Rehydrogenation of MgH2Co-authorH. T. Takeshita;T. Ishikawa;Y. Sasaki;M. Kinouchi;K. Noda;2008/6/24～2008/6/28MH2008 International Symposium on Metal-Hydrogen SystemsReykjavik, Iceland
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PapersDehydrogenation kinetics of Ti-doped NaAlH4 - Influence of Ti precursors and preparation methodsAcademic JournalCo-authorM. Onkawa;S. Zhany;H. T. Takeshita;N. Kuriyama;T. Kiyobayashi;Int. J. Hydrogen Energy33 , 718-7212008～
Academic presentationInfluence of the air exposure in Li-N-H systemCo-authorT. H. Izuhara;K. Katayama;H. T. Takeshita;2007/12～
Influence of the Lithium Hydroxide on Hydrogen Release Property in Li-N-H Hydrogen Storage SystemCo-authorT. H. Izuhara;K. Katayama;H. T. Takeshita;2007/11～PRICM-6, The Sixth Pacific Rim International Conference on Advanced Materials and Processing
Dehydrogenation Behavior of LiBH4-NaAlH4 MixtureCo-authorM. Ikeda;H. Takaoka;H. T. Takeshita;K. Ikeda;S. I. Orimo;2007/11～PRICM-6, The Sixth Pacific Rim International Conference on Advanced Materials and Processing
Influence of Mixing of LiNH2 and LiH on H2 and NH3 Release in Li-N-H SystemCo-authorK. Kobayashi;T. H. Izuhara;H. T. Takeshita;2007/11～PRICM-6, The Sixth Pacific Rim International Conference on Advanced Materials and Processing
Effect of LiH amount on constituent phase
in Li-N-HCo-authorT. H. Izuhara;H. T. Takeshita;K. Kobayashi;A. Miwa;2007/10～2007 X, International Conference “Hydrogen Materials Science and Chemistry of Carbon Nanomaterials”
Observation of particles of Ti doped NaAlH4 and relationship to the reaction kineticsCo-authorM. Adachi;M. Onkawa;H. T. Takeshita;S. Ikeda;T. Kiyobayashi;2007/10～ICHMS’ 2007 X, International Conference “Hydrogen Materials Science and Chemistry of Carbon Nanomaterials”
Separation and storage of hydrogen from mixgture gases using Pd
containing alloysCo-authorK. Noda;H. T. Takeshita;2007/10～ICHMS’ 2007 X, International Conference “Hydrogen Materials Science and Chemistry of Carbon Nanomaterials”
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PapersUnderstanding the effect of titanium species on the decomposition of alanates in homogeneous solutionAcademic JournalCo-authorS． Zhang;A． Taniguchi;Q． Xu;N． Takeichi;H． T． Takeshita;N． Kuriyama;T． Kiyobayashi;J． Alloys Compd．413， (1-2)， 218-2212006～
PapersRelation between Melting and Dehydrogenation Temperatures of LiAlH4Academic JournalCo-authorH． T． Takeshita;Y． Kamada;A Taniguchi;T． Kiyobayashi;K． Ichii;T． Oishi;Mater． Trans．47， (02)， 405-4082006～
PapersFormation of perovskite－type hydrides and thermal desorption processes in Ca－T－H（T=3d transition metals）Academic JournalCo-authorK. Ikeda;S. Kato;K. Ohoyama;Y. Nakamori;H. T. Takeshita;S. Orimo;SCRIPTA MATERIALIA55（9）,827－830.2006～
PapersHydrogenation and dehydrogenation properties for DyNi5-H systemIn refereedAcademic JournalCo-authorH. Senoh;N. Takeichi;H. Tanaka;T. Kiyobayashi;M. Toyouchi;H. T. Takeshita;T. Oishi;N. Kuriyama;Journal of Alloys and Compoundsvol. 389, no. 1-2, pp. 182-1852005/3/8～
PapersAppearance of a novel pressure plateau in RNi5-H (R = rare earth) systemsIn refereedAcademic JournalCo-authorH. Senoh;T. Yonei;H. T. Takeshita;N. Takeichi;H. Tanaka;N. Kuriyama;Materials Transactionsvol.46, no.2, pp. 152-1542005/2～
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PapersStudies of P-C isotherms in RNi5-H (R: La， Pr， Nd， Sm， Gd， Tb and Dy) systemsAcademic JournalCo-authorH． Senoh;N． Takeichi;T． Kiyobayashi;H． Tanaka;H． T． Takeshita;T． Oishi;N． Kuriyama;J． Alloys Compd.404-406， 47-502005～
PapersStructure of nano-crystalline FeTiDx by neutron and X-ray diffractionAcademic JournalCo-authorK． Itoh;H． Sasaki;H． T． Takeshita;K． Mori;T． Ｆｕｋｕｎａｇａ;J． Alloys Compd.404-406， 95-982005～
PapersHydrogenation properties and structural change of HfXZr7-xNi10 (x=0-7)Academic JournalCo-authorH． T． Takeshita;N． Fujiwara;N． Takeichi;H． Senoh;T． Oishi;J． Alloys Compd.404-406， 609-6122005～
PapersHydrides with the perovskite structure：General bonding and stability considerations and the new representative CaNiH3Academic JournalCo-authorT． Sato;D． Noreus;H． T． Takeshita;U．Haussermann;J． Solid State Chem.178 (11)， 3381-33882005～
PapersRe-examination of Zr7Ni10 single-phase regionIn refereedAcademic JournalCo-authorH. T. Takeshita;S. Kondo;H. Miyamura;N. Takeichi;N. Kuriyama;T. Oishi;Journal of Alloys and Compounds376(1-2), 268-2742004/8/11～
PapersSynthesis of CaNiH3 based hydrides by mechanical alloyingIn refereedAcademic JournalCo-authorH. T. Takeshita;T. Furuya;H. Miyamura;N. Kuriyama;Transactions of Materials Research Society of Japan29(5), 2049-20512004/8～
PapersSystematic investigation on hydrogen storage properties of RNi5 (R : rare earth) intermetallic compounds with multi-plateauIn refereedAcademic JournalCo-authorH. Senoh;N. Takeichi;H. T. Takeshita;H. Tanaka;T. Kiyobayashi;N. Kuriyama;MATERIALS SCIENCE AND ENGINEERING BSOLID STATE MATERIALS FOR ADVANCED TECHNOLOGY108(1-2), 96-992004/4/25～
PapersHydrogenation properties and structure of Ti-Cr alloy prepared by mechanical grindingIn refereedAcademic JournalCo-authorN. Takeichi;H. Senoh;H. Tanaka;T. Kiyobayashi;N. Kuriyama;H. T. Takeshita;T. Oishi;MATERIALS SCIENCE AND ENGINEERING BSOLID STATE MATERIALS FOR ADVANCED TECHNOLOGY108(1-2), 100-1042004/4/25～
PapersHydrogenation of nanostructured graphite by mechanical grinding under hydrogen atmosphereIn refereedAcademic JournalCo-authorT. Kiyobayashi;K. Komiyama;N. Takeichi;H. Tanaka;H. Senoh;H. T. Takeshita;N. Kuriyama;MATERIALS SCIENCE AND ENGINEERING BSOLID STATE MATERIALS FOR ADVANCED TECHNOLOGY108(1-2), 134-1372004/4/25～
PapersHydrogenation and dehydrogenation properties of RHNi5 (R-H = heavy rare earth) binary intermetallic compoundsIn refereedAcademic JournalH. Senoh;T. Kiyobayashi;N. Takeichi;H. Tanaka;Q. Xu;H. T. Takeshita;M. Toyouchi;T. Oishi;N. Kuriyama;Materials Transactions45(2), 292-2952004/2～
Academic presentationEffect of Titanium Species in the Dehydrogenation of NaAlH４-Study under Homogenous ConditionsCo-authorTAKESHITA,Hiroyuki;;;;;;;2004～
Academic presentationCo-authorTAKESHITA,Hiroyuki;;;;;;2004～
Academic presentationCo-authorTAKESHITA,Hiroyuki;;;;;2004～
Academic presentationCo-authorTAKESHITA,Hiroyuki;;;;;;2004～
Academic presentationCo-authorTAKESHITA,Hiroyuki;;;;;;;2004～
Academic presentationCo-authorTAKESHITA,Hiroyuki;;;;2004～
Academic presentationCo-authorTAKESHITA,Hiroyuki;;;;;;2004～
Academic presentationCo-authorTAKESHITA,Hiroyuki;;;;;;2004～
Academic presentationCo-authorTAKESHITA,Hiroyuki;;2004～
Academic presentationCo-authorTAKESHITA,Hiroyuki;;;;;;;2004～
Potential of a hybrid hydrogen
storage vessel consisting of an Al-CFRP high pressure vessel and hydrogen storage materialCo-authorN. Takeichi;H. Senoh;N. Kuriyama;H. Tanaka;T. Kiyobayashi;H.Ｔｓｕｒｕｔａ;T. Okita;H. T. Takeshita;T. Takano;4402004～15th World Hydrogen Energy ConferenceYokohama
Hydrogenation properties of Zr7(Ni1-xCux) 10alloysCo-authorH. T. Takeshita;N. Fujiwara;H. Senoh;N. Takeichi;N. Kuriyama;T. Oishi;4612004～15th World Hydrogen Energy ConferenceYokohama
TPD and TEM/EELS analysis of hydrogen states in the graphite ball milled under hydrogenatmosphereCo-authorT. Kiyobayashi;S. Muto;M. Onkawa;T. Kimura;T. Tanabe;H. T. Takeshita;N.Kuriyama;652004～International symposium on metal―hydrogen systems : Fundamentals and applicationsCracow
Understanding the effect of titanium species in the decomposition of NaAlH4～study under homogenous conditionsCo-authorS. Zhang;A. Taniguchi;Q. Xu;N. Takeichi;H. T. Takeshita;N. Kuriyama;T. Kiyobayashi;942004～International symposium on metal-hydrogen systems :Fundamentals and applicationsCracow
Studies of P-C isotherms in RNi5-H(R : La, Pr, Nd, Sm, Gd,Tb, Dy) systemsCo-authorH. Senoh;N. Takeichi;T. Kiyobayashi;H. Tanaka;H. T. Takeshita;T. Oishi;N. Kuriyama;1052004～International symposium on metal-hydrogen systems : Fundamentals and applicationsCracow
On PCT measurement of catalyzed alanatesCo-authorA. Taniguchi;S. Zhang;H. T. Takeshita;T. Oishi;K. Ichii;T. Kiyobayashi;1062004～International symposium on metal-hydrogen systems : Fundamentals and applicationsCracow
Structure of nano-crystalline TiFeDx by neutron and X-ray diffractionCo-authorK. Itoh;H. Sasaki;H. T. Takeshita;K. Mori;T. Fukunaga;1382004～International symposium on metal-hydrogen systems : Fundamentals and applicationsCracow
Hydrogenation properties and structural change of HfxZr7-xNi10 (x=0―7)Co-authorH. T. Takeshita;M. Nakao;N. Fujiwara;H. Senoh;N. Takeichi;N. Kuriyama;T. Oishi;1432004～International symposium on metal-hydrogen systems : Fundamentals and applicationsCracow
PapersAnother unusual phenomenon for Zr7Ni10: structural change in hydrogen solid solution and its conditionsIn refereedAcademic JournalCo-authorHiroyuki T. Takeshita;Nobuaki Fujiwara;Toshio Oishi;Dag Noréus;Nobuhiko Takeichi;Nobuhiro Kuriyama;Journal of Alloys and Compounds360(1-2), 250-2552003/10/6～Zr7Ni10 has three hydrogen occlusion phases, alpha, beta and gamma, and the following unusual features are known for the phase transitions in the Zr7Ni10–H2 system: (1) The intermediate hydride phase (beta) appears only during dehydrogenation but not during hydrogenation, and (2) The continuous hydrogen solid solution phase (alpha) exhibits a much higher hydrogen solubility during hydrogenation than during dehydrogenation. In order to clarify the mechanism about the difference in the hydrogen solubility of the phase, the relation between the pressure-composition isotherms and corresponding structural change has been examined by a conventional volumetric method and X-ray diffraction. Through the examination, we discovered that the crystal structure of the phase, which undergoes hydrogenation followed by dehydrogenation, is different from that of its pure metal phase, where the crystal structure of the dehydrogenated phase changes from an orthorhombic structure to a tetragonal structure. The conditions causing the structural change were then examined, and it has been found that the phase maintains its original orthorhombic structure as long as it is hydrogenated so as not to absorb enough hydrogen to change it to the hydride with a higher hydrogen content (gamma). The phenomenon can be understood as one of the hydrogen-assisted phase transitions such as hydrogen-induced amorphization (HIA) in the sense that the phase transition requires hydrogenation under special conditions.
Papers”Hybrid hydrogen storage vessel”, a novel high-pressure hydrogen storage vessel combined with hydrogen storage materialIn refereedAcademic JournalCo-authorN. Takeichi;H. Senoh;T. Yokota;H. Tsuruta;K. Hamada;H. T. Takeshita;H. Tanaka;T. Kiyobayashi;T. Takano;N. Kuriyama;International Journal of Hydrogen Energy28(10), 1121-11292003/10～Potential of a novel hydrogen storage vessel, ”hybrid hydrogen storage vessel”, combining an aluminum–carbon fiber reinforced plastic (Al–CFRP) composite vessel and hydrogen storage alloy, is reported through calculation of the weight and volume of the hydrogen storage system for 5 kg of hydrogen. Evaluation of this system showed that the concept of the hybrid hydrogen storage vessel allowed us to realize a hydrogen storage system advantageous in both gravimetric and volumetric hydrogen density compared with conventional hydrogen storage techniques. The hybrid vessel requires a hydrogen storage alloy with a higher volumetric hydrogen density as well as a higher gravimetric density, and with a higher equilibrium hydrogen pressure than the hydrogen storage alloys which have been used for conventional hydrogen storage vessels.
PapersHydrogenation Properties of RNi5 (R: Rare Earth) Intermetallic Compounds with Multi Pressure PlateauxIn refereedAcademic JournalCo-authorH. Senoh;N. Kuriyama;H. T. Takeshita;H. Tanaka;T. Kiyobayashi;N. Kuriyama;Materials TransactionsVol. 44 (9), 1663-16662003/9～Some hydrogen storage materials with the hexagonal CaCu5-type crystal structure have two pressure plateaux during hydrogen absorption and desorption processes. To clarify the correlation of hydrogenation properties between two plateaux, we investigated the pressure-composition isotherms of several binary RNi5 (R=La, Ce, Pr, Nd and Sm) intermetallic compounds at pressures up to 35MPa and at temperatures ranging from 196 to 423K by use of a modified Sieverts' method. We also determined the unit cell volume of the compounds to correlate the hydrogenation properteis with the crystal structure. It was found that RNi5 compounds had qualitatively similar hydrogenation properties in that two well-separated plateaux indicated the existence of two hydrides with the compositions of RNi5H3-4 (beta phase) and RNi5H6-7 (gamma phase) except CeNi5. Simlilar to the lower plateau pressure, the higher plateau pressure increases with increasing the atomic number to R element or with decreasing the unit cell volume of these compounds. For LaNi5-H2 system, the pressure gap between two plateaux expands with increasing temperature, indicating that the absolute value of enthalpy of dehydrogenation (delta H) of beta hydride is smaller than that of gamma hydride or delta H(beta)delta H(gamma). The maximum hydrogen content of each RNi5 compound exceeds six hydrogen atoms per formula unit and some compounds absorb the hydrogen to reach the hydride composition of RNi5H7 without new plateau.
PapersDeterioration behavior of a multi-phase vanadium-based solid solution alloy electrodeIn refereedAcademic JournalCo-authorN. Kuriyama;M. Tsukahara;K. Takahashi;H. Yoshinaga;H. T. Takeshita;T. Sakai;Journal of Alloys and Compounds356(1-2), 738-7412003/8/11～
PatentsTAKESHITA Hiroyuki T.;;;;;;2003/7/18～
Academic presentationHydrogenation of nanostructured graphite by mechanical grinding under hydrogen atmosphereCo-authorT. Kiyobayashi;K. Komiyama;N. Takeichi;H. Tanaka;H. Senoh;H. T. Takeshita;N. Kuriyama;2003/6/12～E-MRS 2003 Spring meeting, Symposium C
Academic presentationSystematic investigation on hydrogen storage properties of RNi5 (R: Rare Earth) intermetallic compounds with multi-plateauCo-authorH. Senoh;N. Takeichi;H. Tanaka;T. Kiyobayashi;N. Kuriyama;H. T. Takeshita;2003/6/12～E-MRS 2003 Symposium C
Academic presentationStructure and Hydrogenation properties of Zr7Ni10 prepared by quenchingCo-authorS. Kondo;N. Fujiwara;H. T. Takeshita;T. Oishi;H. Miyamura;N. Takeichi;T. Kiyobayashi;H. Tanaka;N. Kuriyama;2003/6/12～E-MRS 2003, Symposium C
Academic presentationHydrogenation properties and structure of Ti-Cr alloy prepared by mechanical grindingCo-authorN. Takeichi;H. Senoh;H. Takanak;T. Kiyobayashi;N. Kuriyama;H. T. Takeshita;T. Oishi;2003/6/12～E-MRS 2003 Symposium C
Academic presentationHydrogenation properties of graphite mechanically ground with non-metal mill pot and ballsUnrefereedCo-authorH. T. Takeshita;K. Komiyama;T. Kiyobayashi.;N. Kuriyama;2003/3/26～International Symposium on Nanotechnology and Materials for the EnvironmentIt was reported by Orimo and Fukunaga that mechanical grinding under hydrogen atmosphere significantly enhanced hydrogen storage capacity of graphite [1]. In order to clarify the mechanism, the effect of materials of mill pots and balls on the hydrogenation properties of graphite was investigated. Two kinds of pots and balls were used for the milling of graphite under hydrogen atmosphere of 0.6MPa; the one was made of Cr steel and the other was made of agate. The graphite prepared in Cr steel pot exhibited the hydrogen storage capacity of 2.2 mass%, indicating the enhancement of hydrogen storage capacity of graphite by ball milling, although the value was smaller than that reported (7.4 mass%) [1], whereas, interestingly, the graphite milled with agate balls in the agate pot exhibited very small hydrogen storage capacity (0.1 to 0.2 mass%). Further experiments were performed to clarify the effect of particle size and metal impurity on the hydrogen storage capacity of nano-structured graphite. The results will be reported in the Poster session in details.
[1]S. Orimo, T. Matsushima, H. Fujii, T. Fukunaga, G. Majer, J. Appl. Phys., 90 (2001), 1545.
PapersPhase transformation in Ti-Cr alloys by mechanical grindingIn refereedAcademic JournalCo-authorN. Takeichi;H. T. Takeshita;H. Tanaka;T. Kiyobayashi;N. Kuriyama;Laves phase;Solid solution phase;Titanium-Chromium system;Crystal structure;X-ray techniques;Mechanical grinding;Materials Letters57(8), 1395-13992003/2～The effect of mechanical grinding on phase transformation in Ti–Cr alloys with nominal compositions of TiCr2-x (x=0, 0.2 and 0.5) was studied on phase transformation by mechanical grinding (MG). An X-ray diffraction (XRD) technique was applied for the identification of the constituent phases in the samples ground for various periods ranging from 0 to 12 h. The
results indicated that the constituent phases changed from the mixture of a C15 and C14 Laves phases stable at ambient temperatures to a bcc phase stable at high temperatures such as 1643 K with an increase in grinding time. It was also found that, after 12 h of grinding, we could obtain samples composed of only a bcc phase within the detection ability of the X-raydiffraction apparatus.
PapersSynthesis of CaNi1-xPdx (0.1≤x≤1) alloys and hydrogenation properties of CaPdIn refereedAcademic JournalCo-authorTAKESHITA,Hiroyuki;Ca-Pd-Ni alloys;metal hydrides;X-ray diffraction;hydrogen storage materials;Journal of Alloys and Compounds347(1-2), 231-2382002/12/16～An evaluation of the substitution of a third element for the constituent elements (Ca, Ni) in the compound was conducted in order to obtain information about stabilization of the CaNi compound which does not exist as a stable phase. Prior to the experimental study of the substitution, the candidates for the third element were investigated using Miedema's semi-empirical model, from the standpoint of formation enthalpy, and, as a result, Pd was chosen as the element to stabilize the compound. The samples with the nominal compositions of CaNi1-xPdx (0.1≤x≤1) were prepared by sintering and high frequency heating, and the constituent phases and hydrogenation properties were examined. New ternary phases such as Ca1(Ni, Pd)1 were not obtained under the present conditions; however, some pieces of new information such as the substitution of Ni for Pd in CaPd2 and reversible hydrogenation of CaPd at 373K were obtained through the examinations.
CommentaryUnrefereedIn-house publicationSingle-AuthorTAKESHITA,Hiroyuki;2002/11/30～
LectureSingle-AuthorTAKESHITA,Hiroyuki;2002/11/19～
Academic presentationX-ray Diffraction and Solid NMR Studies of Doped NaAlH4: Fundamental Insights into a Promissing New Hydrogen Storage MaterialCo-authorD. Sun K;K. Kumashiro;W. Niemczura;K. Murphy;T. Kiyobayashi;H. T. Takeshita;N. Kuriyama;C. M. Jensen;2002/9/5～International Symposium on Metal-Hydrogen Systems: Fundamentals and Applications
Academic presentationImpedance Spectroscopy of a Vanadium-Based Solid Solution Alloy ElectrodeCo-authorN. Kuriyama;M. Tsukahara;K. Takahashi;H. Yoshinaga;H. T. Takeshita;T. Sakai;2002/9/5～International Symposium on Metal-Hydrogen Systems: Fundamentals and Applications
Academic presentationThe Hydrogenation of Ti-Cr Alloys With BCC Structure Prepared By Mechanical GrindingCo-authorN. Takeichi;H. T. Takeshtia;T. Kaneko;T. Oishi;H. Tanaka;T. Kiyobayashi;N. Kuriyama;2002/9/5～International Symposium on Metal-Hydrogen Systems: Fundamentals and Applications
Academic presentationHydrogen Assisted Phase Transition of Zr7Ni10Co-authorH. T. Takeshita;D. Noreus. N. Takeichi;T. Kiyobayashi;H. Tanaka;N. Kuriyama;2002/9/3～International Symposium on Metal-Hydrogen Systems: Fundamental and Applications
Academic presentationX-ray Diffarction and Solid NMR Studies of Doped NaAlH4: Fundamental Insights into a Promising New Hydrogen Storage MaterialCo-authorD. Sun;K. K. Kumashiro;W. Niemczura;K. Murphy;T. Kiyobayashi;H. T. Takeshita;N. Kuriyama;C. M. Jensen;2002/9/3～International Symposium on Metal-Hydrogen Systems: Fundamental and Applications
Academic presentationHydrogen Storage Properties of AB5-Type Alloys at High Hydrogen PressureCo-authorH. Senoh;H. T. Takeshita;N. Takeichi;H. Tanaka;T. Kiyobayashi;N. Kuriyama;2002/9/3～International Symposium on Metal-Hydrogen Systems: Fundamentals and Applications
Academic presentationStructural change of hydrogen solid solution phase of Zr7Ni10Co-authorN. Fujiwara;H. T. Takeshita;K. Sakaki;T. Oishi;Y. Shirai;2002/9/2～International Symposium on Metal-Hydrogen Systems: Fundamental and Applications
Academic presentationHydrogenation property of CaPd2: Exception to HIA criterion?Co-authorH. T. Takeshita;Y. Sakamoto;H. Tanaka;N. Takeichi;T. Kiyobayashi;H. Senoh;N. Kuriyama;2002/9/2～International Symposium on Metal-Hydrogen Systems: Fundamental and Applications
PapersHydrogenation of Body-Centered-Cubic Titanium-Chromium Alloys Prepared by Mechanical GrindingIn refereedAcademic JournalCo-authorN. Takeichi;H. T. Takeshita;T. Oishi;T. Kaneko;H. Tanaka;T. Kiyobayashi;N. Kuriyama;hydrogen storage materials;Laves phase;bcc structure;solid solution phase;titanium-chromium system;X-ray diffraction;mechanical grinding;Materials Transactions43(8), 2161-21642002/8/31～The C15 and C14 intermetallic TiCr2-x (x=0, 0.2 and 0.5) compounds were subjected to grinding in a high-energy ball mill. The X-ray diffraction profiles showed that the crystal structure transformed from C15 and C14 to bcc after mechanical grinding for 57.6ks. The hydrogenation properties of the TiCr2-x samples were examined by differential thermal analysis and pressure-composition isotherm measurements. The sample reacted with hydrogen at 5MPa and 523K by maintaining the bcc structure. An higher hydrogen content was observed for the sample with the higher Ti content. The maximum hydrogen content of TiCr2.0 , TiCr1.8 and TiCr1.5 was found to be about 0.32, 0.36 and 0.47H/M at 313K, respectively, at 8MPa.
PapersX-ray diffraction studies of titanium and zirconium deped NaAlH4: elucidation of doping induced structural changes and their relationship to enhanced hydrogen storage propertiesIn refereedAcademic JournalCo-authorD. Sun;T. Kiyobayashi;H. T. Takeshita;N. Kuriyama;C. M. Jensen;vacancy formation;metal hydrides;alanates;hydrogen absorbing materials;X-ray diffraction;Journal of Alloys and Compounds337(1-2), L8-L112002/5/2～X-ray diffraction patterns of NaAlH4 doped with up to 10 mol% of either titanium or zirconium do not contain Bragg peaks for the buld metals or their aluminium alloys. Instead the hydride lattice parametersa andc undergo significant contraction upon 2 mol% of doping and then expand as the doping level increases from 2 to 5 mol%. These results are explained by a model that entails substitution of sodium cations by variable valence transition metal cations and the creation of Na+ vacancies in the bulk hydride lattice.
PapersReproducible Evaluation of Characteristics of a Metal Hydride Electrode Composed of MH Powder and Copper PowderIn refereedAcademic JournalCo-authorN. Kuriyama;T. Sakai;H. T. Takeshita;H. Tanaka;T. Kiyobayashi;N. Takeichi;I. Uehara;Journal of Alloys and Compounds330-332, pp.771-7752002/1～
PapersHydrogen Adsorption in Carbonaceous MaterialsIn refereedAcademic JournalCo-authorT. Kiyobayashi;H. T. Takeshita;H. Tanaka;N. Takeichi;A. Zuettel;L. Schlapbach;N. Kuriyama;Journal of Alloys and Compounds330-332, pp.666-6692002/1～
PapersHydrogenation characteristics of Ti2Ni and Ti4Ni2X (X=O, N, C)In refereedAcademic JournalCo-authorH. T. Takeshita;H. Tanaka;T. Kiyobayashi;N. Takeichi;N. Kuriyama;Journal of Alloys and Compounds330-332, pp. 517-5212002/1～
PapersDisproportionation of CaNi3 hydride: Formation of new hydride, CaNiH3In refereedAcademic JournalCo-authorH. T. Takeshita;T. Oishi;N. Kuriyama;Journal of Alloys and Compounds333(1-2), pp. 266-2732002/1～
PapersHigh Pressure Experiments on Hydrogen Storage MaterialsIn refereedAcademic JournalCo-authorJ. Chen;T. Sakai;N. Kitamura;H. Tanaka;H. T. Takeshita;T. Kiyobayashi;N. Kuriyama;D. Harimoto;H. Nagai;Y. Fukai;Journal of Alloys and Compounds330-332, pp. 162-1652002/1～
PapersNanocrystalline Ti-Doped Li3AlH6 as a Reversible Hydrogen Storage MaterialIn refereedAcademic JournalCo-authorJ. Chen;N. Kuriyama;H. T. Takeshtia;T. Sakai;Advanced Engineering Materials3(9), pp. 695-6982001/9～
PapersA Novel Thermic Process for Producing V-based Solid Solution Type Hydrogen Storage AlloyIn refereedAcademic JournalCo-authorA. Kawabata;H. Yoshinaga;M. Tsukahara;T. Sakai;S. Sakurai;Y. Kamiya;K. Takahashi;H. T. Takeshita;N. Kuriyama;J. Shi;Materials Transactions42(8), pp. 1794-17992001/8～
PapersHigh pressure synthesis of amorphous MgNi1.02H2.2In refereedAcademic JournalCo-authorJ.Chen;T.Sakai;N.Kitamura;H.T.Takeshita;N.Kuriyama;Journal of the American Chemical Society123, pp. 6193-61942001/6～
PapersSynthesis and characterization of nanocrystalline Mg2CoH5 obtained by mechanical alloyingIn refereedAcademic JournalCo-authorJ . Chen;H. T. Takeshita;D. Chartouni;N. Kuriyama;T. Sakai;Journal of Materials Science36, pp. 5829-58342001～
PapersReversible Hydrogen Storage via Titanium-Catalyzed LiAlH4 and Li3AlH6In refereedAcademic JournalCo-authorJ. Chen;N. Kuriyama;Q. Xu;H. T. Takeshita;T. Sakai;The Journal of Physical Chemistry B105(45), pp. 11214-112202001～
PapersHigh pressure synthesis of the Mg0.90Al0.08Ni0.94V0.08H1.6In refereedAcademic JournalCo-authorJ. Chen;T. Sakai;N. Kitamura;H. T. Takeshita;N. Kuriyama;Metal and Materials6, 605-6082000/12～
PapersHydrogenation characteristics of ternary alloys containing Ti4Ni2X (X=O, N, C)In refereedAcademic JournalCo-authorH. T. Takeshita;H. Tanaka;N. Kuriyama;T. Sakai;I. Uehara;M. Haruta;Journal of Alloys and Compounds311(1-2), 188-1932000/9～
PapersReversible hydrogen absorption and desorption achieved by irreversible phase transitionsIn refereedAcademic JournalCo-authorH. T. Takeshita;T. Kiyobayashi;H. Tanaka;N. Kuriyama;M. Haruta;Journal of Alloys and Compounds311(1-2), L1-L42000/9～
PapersHydrogen storage and electrode properties of V-based solid solution type alloys prepared by a thermic processIn refereedAcademic JournalCo-authorM. Tsukahara;T. Kamiya;K. Takahashi;A. Kawabata;S. Sakurai;J. Shi;H. T. Takeshita;N. Kuriyama;T. Sakai;Journal of Electrochemical Society147, 2941-29442000/8～
PapersA high pressure observation of the Mg2NiH4-H systemIn refereedAcademic JournalCo-authorJ.Chen;T. Sakai;N. Kitamura;H. T. Takeshita;H. Tanaka;N. Kuriyama;D. Harimoto;N. Nagai;Y. Fukai;Journal of Alloys and Compounds307(1-2), L1-L52000/6～
PapersHydrogen storage alloys with PuNi3-type structure as metal hydride electrodesIn refereedAcademic JournalCo-authorJ.Chen;N. Kuriyama;H. T. Takeshita;H. Tanaka;T. Sakai;M. Haruta;Electrochemical and Solid-State Letters3(6), 249-2522000/6～
PapersIn refereedAcademic JournalCo-authorTAKESHITA,Hiroyuki;;;;;;;TAKESHITA Hiroyuki T.;;;2000/4～
PapersHydriding properties of LaNi3 and CaNi3 and their substitutes with PuNi3-type structureIn refereedAcademic JournalCo-authorJ. Chen;H. T. Takeshita;H. Tanaka;N. Kuriyama;T. Sakai;I. Uehara;M. Haruta;Journal of Alloys and Compounds302(1-2), 304-3132000/4～
PatentsTAKESHITA,Hiroyuki;TAKESHITA Hiroyuki T.;;;;2000/2/25～
PapersHydrogenation characteristics of Ti4Cu2OIn refereedAcademic JournalCo-authorH. T. Takeshita;H. Tanaka;N. Kuriyama;T. Sakai;I. Uehara;M. Haruta;Journal of Alloys and Compounds298(1-2), 114-1182000/2～
PapersInfluence of carbon on electrode properties of V-Ti-Ni type hydrogen storage alloyIn refereedAcademic JournalCo-authorJ. Shi;M. Tsukahara;H. T. Takeshita;N. Kuriyama;T. Sakai;Journal of Alloys and Compounds293-295, 716-7201999/12～
PatentsTAKESHITA,Hiroyuki;TAKESHITA Hiroyuki T.;;;;;1999/11/12～
PatentsTAKESHITA,Hiroyuki;TAKESHITA Hiroyuki T.;;;;1999/9/3～
PapersInfluence of carbon impurity on microstructures and electrode properties for V-based battery alloysIn refereedAcademic JournalCo-authorJ. Shi;T. Sakai;H. T. Takeshita;N. Kuriyama;M. Tsukahara;Journal of Alloys and Compounds290(1-2), 267-2721999/9～
PapersScanning Tunneling Microscopy In-Situ Observation of Phase-Selective Cathodic Hydrogenation of a V-Ti-Ni-Based Multiphase Alloy ElectrodeIn refereedAcademic JournalCo-authorN. Kuriyama;D. Chartouni;M. Tsukahara;K. Takahashi;H. T. Takeshita;H. Tanaka;L. Schlapbach;T. Sakai;I. Uehara;Electrochemical and Solid-State Letters1, 37-381998/6～
PatentsUS patent no. 5728277, ”Hydrogen Occlusion Electrode”T. Sakai;H. T. Takeshita;N. Kuriyama;H. Tanaka;I. Uehara;1998/3/17～
PapersElectrochemical Activity Enhancement of a LaNi4.7Al0.3 Electrode Treated with an Alkaline Solution Containing H2O2In refereedAcademic JournalCo-authorN. Kuriyama;T. Sakai;H. Miyamura;H. Tanaka;H. T. Takeshita;I. Uehara;Journal of Alloys and Compounds253-254, 598-6001997/5～
PapersHydrogenation Characteristics of TiFe1-xPdx (0.05
X0.30) AlloysIn refereedAcademic JournalCo-authorI. Yamashita;H. Tanaka;H. T. Takeshita;N. Kuriyama;T. Sakai;I. Uehara;Journal of Alloys and Compounds253-254, 238-2401997/5～
X0.30) AlloysIn refereedAcademic JournalCo-authorI. Yamashita;H. Tanaka;H. T. Takeshita;N. Kuriyama;T. Sakai;I. Uehara;Journal of Alloys and Compounds253-254, 238-2401997/5～PapersIn refereedAcademic JournalCo-authorTAKESHITA,Hiroyuki;TAKESHITA Hiroyuki T.;;;;1996/4～
PapersIn refereedAcademic JournalCo-authorTAKESHITA Hiroyuki T.;;;;;1996/3～
PapersIn refereedAcademic JournalCo-authorTAKESHITA Hiroyuki T.;;;;1995/9～
CommentaryIn refereedAcademic JournalCo-authorTAKESHITA Hiroyuki T.;;;1994/4～
PapersIn refereedAcademic JournalCo-authorTAKESHITA Hiroyuki T.;;;;1993/12～
Community Activities
- International Energy Agency, Task 17, Expert 2001～2006
Research Activities Overseas
- OtherDec. 9,2002-Dec. 15,2002
Participation in International Conferences
- International Symposium on Metal-Hydrogen Systems, Fundamentals and Applications Sep.1,2002-Sep. 6,2002
- NANOENERGY 2002 Dec.11,2002-Dec. 13,2002
- International Symposium on Metal-Hydrogen Systems, Fundamentals and Applications Sep.5,2004-Sep. 10,2004
- IUMRS-ICEM7 Jul.4,2005-Jul. 8,2005
- 2008 MRS Fall Meeting Dec.1,2008-Dec. 4,2008
- 15th World Hydrogen Energy Conference 2004
- International symposium on metal―hydrogen systems : Fundamentals and applications 2004
- MH2006 International Symposium on Metal－Hydrogen systems －Fundamentals and Applications－ Oct.2,2006-Oct. 6,2006
- ICHMS' 2007 X, International Conference “Hydrogen Materials Science and Chemistry of Carbon Nanomaterials” Oct.2007
- PRICM-6, The Sixth Pacific Rim International Conference on Advanced Materials and Processing Nov.2007
- MH2008 International Symposium on Metal-Hydrogen Systems Jun.24,2008-Jun. 28,2008
Courses Taught
- Physical Chemistry I (Lecture and Exercises)
- Physical Chemistry II (Lecture and Exercises)
- Crystal Structure and X-Ray Diffraction Method
- Experiments of Materials Engineering I
- Experiments of Materials Engineering II
- Exercises in Thesis Projects I and II
- Thesis Projects I
- Thesis Projects II
- Exercises in Materials Science II
- SeminarI（Chemistry and Materials Engineering)
- SeminarII（Chemistry and Materials Engineering)
- SeminarIII（Chemistry and Materials Engineering)
- SeminarIV（Chemistry and Materials Engineering)
- Advanced Crystal and Electronic Structure
- Material Energy Technology
- Metallurgy and Metallic Materials
- Material Energy Technology
- Personal Information
- Research Activities
- Research Activities
- Community Service
- Courses Taught