Kyushu University Academic Staff Educational and Research Activities Database
List of Presentations
Etsuo Akiba Last modified date:2019.05.14

Research Professor / Hydrogen Storage Division / International Research Center for Hydrogen Energy

1. EDALATI KAVEH, Ryoko Uehara, Yuji Ikeda, 李 海文, EMAMI MEIBODY HODA SADAT, 有田 誠, 田中功, 秋葉 悦男, 堀田 善治, Development of New Mg-Based Hydrogen Storage Materials by Binding-Energy Engineering, 日本金属学会2016年秋期大会, 2016.09, Mg-based hydrides are considered as potential candidates for solid-state hydrogen storage. However, the main drawback of Mg-based hydrides is their high thermodynamic stability, and thus their high dehydrogenation temperature. The objective of this study is to design new Mg-based hydrides with low hydrogen binding energies, which can exhibit reversible hydriding/dehydriding features below 373 K. First-principles calculations using a concept of “binding-energy engineering” were employed to design new compounds. Mg4NiPd and Mg4NiSn were selected as two possible candidates with low hydrogen binding energies. The calculations suggested that Mg4NiPd with the B2-type structure and Mg4NiSn with the amorphous structure should form, if the elements are mixed at the atomic scale. Calculations also confirmed that Mg4NiPd exhibits interstitial sites with low hydrogen binding energy, which makes it appropriate for hydrogen storage at low temperature.
For experiments, both Mg4NiPd and Mg4NiSn were first prepared by ingot casting. Since the as-cast materials contained several phases, the materials were mechanically homogenized using the high-pressure torsion (HPT) method to achieve single phases. In good agreement with the first-principles calculations, the crystal structure of Mg4NiPd and Mg4NiSn after mechanical processing using the HPT method contained B2-type structure and amorphous structure, respectively. The effect of HPT processing on the atomic-scale mixing of elements in Mg4NiPd and the formation of the B2-type structure is shown in Figs. 1 and 2, respectively. Examination of the HPT-processed materials by pressure-composition isotherms confirmed that both Mg4NiPd and Mg4NiSn can reversibly absorb and desorb hydrogen below 373 K.
In summary, this study suggests that a combination of first-principles calculations and HPT processing is effective to design new materials for hydrogen storage at low temperature..
2. LIN HUAIJUN, LI Hai-Wen, PAIK BISWAJIT, WANG JIANHUI, Etsuo Akiba, Hydrogen storage property of three-component LiNH2-Mg(NH2)2-LiH composites
, 21st World Hydrogen Energy Conference 2016, 2016.06.
3. 秋葉 悦男, S. Itano, H. Hirano, K. Ikeda, T. Otomo, Crystal structure and hydrogen occupation sites of Ti-V-Cr hydrogen absorbing alloys, 15th International Symposium on Metal-Hydrogen Systems, 2016.08, Ti based BCC alloys especially Ti-V-Cr alloys are one of the most realistic candidates for on-board hydrogen storage because they have about 4 wt% hydrogen capacity under ambient conditions. Reaction rate and other properties are also appropriate for that purpose. However, a part of hydrogen stored is not released under working condition of fuel cell vehicle. To understand the hydrogen that cannot be desorbed, crystal structure analysis is the first step of investigation but Ti-V-Cr is transparent to neutron because the sum of neutron scattering lengths is almost zero. Therefore, crystal structure of Ti-V-Cr hydrides has not been studied indetail..
4. LI Hai-Wen, Liqing He, Hironori NAKAJIMA, Y. Filinchuk, Son-Jong Hwang, 秋葉 悦男, Hans Hagemann, Torben R. Jensen, Material Designing of Metal Boranes for Energy Storage, 15th International Symposium on Metal-Hydrogen Systems, 2016.08.
5. KAVEH EDALATI, EMAMI MEIBODY HODA SADAT, Yuji Ikeda, Hideaki Iwaoka, Isao Tanaka, 秋葉 悦男, Zenji Horita, Hydrogen Storage Performance of Mg-Zr Phases Synthesized by High-Pressure Torsion (HPT), 15th International Symposium on Metal-Hydrogen Systems, 2016.08, Mg and Zr, which are immiscible in the liquid and solid states, were mixed at the atomic scale using the high-pressure torsion (HPT) method. In addition to supersaturated hcp phase, other metastable phases were also formed: bcc or ordered bcc-based phase (as shown in Fig. 1a) and fcc phase (as shown in Fig. 1b). The HPT-processed Mg-Zr absorbed ~1 wt.% of hydrogen under 9 MPa in ~20 s at room temperature and fully desorbed the hydrogen in the air at room temperature. The fast hydrogen absorption and desorption was attributed to the presence of Mg-rich nanoclusters, as shown in Fig. 1c. First-principles phonon calculations, as summarized in Fig. 2, revealed that the disordered hcp and fcc phases were dynamically stable in the whole composition range of the Mg-Zr system. However, the bcc or bcc-based ordered phases (B2 and D03), were dynamically stable only under limited conditions in the Mg-rich compositions. Details of this study will appear in Acta Materialia..
6. LIN HUAIJUN, 李 海文, 秋葉 悦男, Study on the Effect of Ce-based Additives on Hydrogen Storage Properties of Amide/Hydride Composites, 15th International Symposium on Metal-Hydrogen Systems, 2016.08, Amide/hydride composites are a group of promising candidates for hydrogen storage due to the reversible hydrogen storage capacity of 5-10 wt% and moderate enthalpy change of hydrogenation/dehydrogenation.
Nevertheless, the sluggish hydrogenation/dehydrogenation kinetics together with emission of NH3 during dehydrogenation seriously impedes their practical applications1-3. In the present work, the effect of Ce-based additives on hydrogen storage properties of a single amide and amide/hydride composites has been studied.Several Ce-based additives, including Ce, CeO2, CeF3 and CeF4, have been doped into LiNH2 and the LiNH2-LiH composite using ball milling.
7. Hadi Razavi-Khosroshahi, KAVEH EDALATI, Masashige Hirayama, EMAMI MEIBODY HODA SADAT, Makoto ARITA, Miho Yamauchi, Hidehisa Hagiwara, Shintaro Ida, Tatsumi Ishihara, 秋葉 悦男, Zenji Horita, Masayoshi Fujii, Photocatalytic hydrogen generation under visible light on nanostructuredTiO2-II stabilized by high-pressure torsion, International Workshop on Giant Straining Process for Advanced Materials in 2016 (GSAM2016), 2016.07.
8. 秋葉 悦男, Hydrogen storage materials: state-of-the-art and future prospect, International Workshop on Giant Straining Process for Advanced Materials in 2016 (GSAM2016), 2016.07, Hydrogen exists as gas under ambient conditions. Therefore, energy density of hydrogen is significantly lower than solid and liquid fuels. Recently, hydrogen is expected to the future secondary energy but its storage and transportation are the serious issue because of its energy density.
Hydrogen storage materials in both solid and liquid phases are promising candidate to store and transport hydrogen in various scales.
For commercially available fuel cell vehicles, light-weighted high-pressure cylinders with hydrogen pressure of 70 MPa are used to realize the similar cruising range to conventional internal combustion engine vehicles. Weight and volume hydrogen densities are 5.7 wt % and around 25 g/L as a system.
Hydrogen storage materials can realize much higher hydrogen density with lower pressure for various applications including vehicles and stationary energy storage. Wide range of R & D on hydrogen storage materials from fundamentals to various applications have been carried out in Japan. In this review, activities from 1970’s will be summarized and an exiting prospect will also be shown.
9. 秋葉 悦男, Hydrogen storage for stationary and mobile applications, UNSW – I2CNER 1st Energy Workshop, 2016.07.
10. EDALATI KAVEH, 松尾元彰, EMAMI MEIBODY HODA SADAT, 板野祥大, Ali Alhamidi, STAYKOV ALEKSANDAR, D. J. Smith, 折茂慎一, 秋葉 悦男, 堀田善治, Hydrogen storage performance of TiFe-based compounds processed by HPT, 9th Pacific Rim International Congress on Advanced Materials and Processing (PRICM-9) , 2016.08.
11. 大谷紀子, 桑原彰秀, 小川貴史, 世古敦人, 田中功, 秋葉 悦男, 松田 潤子, First-principles study of Ti-V solid solutions using cluster expansion method, 9th Pacific Rim International Congress on Advanced Materials and Processing (PRICM-9), 2016.08.
13. 秋葉 悦男, 板野 祥大, 平野 弘将, 松田 潤子, 池田一貴, 大友季哉, Crystal structure analysis of Nb doped Ti-V-Cr hydrogen absorbing alloys using neutron diffraction, Pacifichem2015, 2015.12.
14. Etsuo Akiba, Kyushu University Hydrogen Project:  Challenges to realize a hydrogen society
, The Road to a Hydrogen Society: Prospects for Developing Zero-Emission Fuel and Outlook for U.S.-Japan Cooperation , 2016.04.
15. LIN HUAIJUN, LI Hai-Wen, 秋葉 悦男, The Effect of Ce-based Additives for Hydrogenation/Dehydrogenation of Amide/Hydride Composites, 日本金属学会2016年春期大会, 2016.03.
16. EDALATI KAVEH, 松尾元彰, EMAMI MEIBODY HODA SADAT, Ali Alhamidi, STAYKOV ALEKSANDAR, D. J. Smith, 折茂慎一, 秋葉 悦男, 堀田善治, Influence of HPT on Hydrogen Storage Performance of TiFe-Mn Compounds

, 日本金属学会2016年春期大会, 2016.03.
17. 秋葉 悦男, EDALATI KAVEH, 平野 弘将, 堀田善治, 板野 祥大, 池田一貴, 大友季哉, Ti Based Hydrogen Storage Materials for Stationary and Mobile Applications, World Hydrogen Technology Convention 2015, 2015.10.
18. 秋葉 悦男, Hydrogen and Fuel Cell Developments in Japan, World Hydrogen Technology Convention 2015, 2015.10.
19. LIN HUAIJUN, LI Hai-Wen, PAIK BISWAJIT, WANG JIANHUI, 秋葉 悦男, Effect of KH addition on hydrogen storage kinetics, thermodynamics and cycling ability of the three-component LiNH2-Mg(NH2)2-4LiH composite, 日本金属学会2015年秋期大会, 2015.09.
20. Hyunjeong Kim, 榊浩司, 浅野耕太, 齋藤 寛之, 米田 安宏, 町田 晃彦, 綿貫 徹, 秋葉 悦男, 中村優美子, Insight into CaLi2-xMgx hydride phase, 日本金属学会2015年秋期大会, 2015.09.
21. EDALATI KAVEH, EMAMI MEIBODY HODA SADAT, STAYKOV ALEKSANDAR, David J. Smith, 秋葉 悦男, 堀田善治, Potential of Metastable Mg-Ti Phases Produced by HPT for Hydrogen Storage, 日本金属学会2015年秋期大会, 2015.09.
22.   王 国良, LI Hai-Wen, 秋葉 悦男, H. Oyama, F. Kato, Zr-based Laves Phase Alloys for Ni-Metal Hydride Battery, 日本金属学会2015年秋期大会, 2015.09.
23. Huaiyu Shao, 秋葉 悦男, NaCl-type structure Ti-V-C based materials for hydrogen storage, 日本金属学会2015年秋期大会, 2015.09.
24. Etsuo Akiba, Ti based Hydrogen Storage Materials for Mobile and Stationary Applications, IUPAC-2015 45th World Chemistry Congress, 2015.08.
26. EDALATI KAVEH, EMAMI MEIBODY HODA SADAT, STAYKOV ALEKSANDAR, Toshifumi Hongo, Hideaki Iwaoka, 秋葉 悦男, 堀田善治, Development of Mg-Based Hydrogen Storage Materials Using
High-Pressure Torsion
, 日本金属学会2015年春期大会, 2015.03.
27. Etsuo Akiba, Improvement of Activation and Re-hydrogenation Behaviors of TiFe, 華南工科大学講演会, 2014.12.
28. Etsuo Akiba, Hydrogen Storage in Japan -Recent Progress and Future prospect-, Hy-SEA 2014 Hydrogen Storage - Embrittlement - Applications, 2014.10.
29. Etsuo Akiba, LI Hai-Wen, Metal borohydrides for high-capacity solid-state hydrogen storage, 2nd International Symposium on Energy Challenges and Mechanics (ECM2), 2014.08.
30. Etsuo Akiba, Improvement of Activation and Re-hydrogenation Behaviors of TiFe, International Symposium Metal-Hydrogen Systems (MH2014), 2014.07.
31. Etsuo Akiba, Hydrogen Storage Properties of Mg-based Materials, CIMTEC 2014 6th Forum on New Materials, 2014.07.
32. Etsuo Akiba, Hydrogen Storage and Transport: State-of-art and Future, Grand Renewable Energy 2014, 2014.06.
33. Etsuo Akiba, Every Hydrogen is Good Hydrogen, MH2012, 2012.10.