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and their Zr-O surface modified electrodesAbe, Machiko*; Iba, Hideki*; Suzuki, Kota*; Minamishima, Hiroaki*; Hirayama, Masaaki*; Tamura, Kazuhisa; Mizuki, Junichiro*; Saito, Tomohiro*; Ikuhara, Yuichi*; Kanno, Ryoji*
Journal of Power Sources, 345, p.108 - 119, 2017/03
Times Cited Count：11 Percentile：38.74(Chemistry, Physical)The surface structure of the Li(Ni, Co, Mn)O electrode was studied during charge/discharge process using electrochemical methods and X-ray/Neutron scattering techniques. It was found that during charge/discharge process the coverage of spinel structure increased. The spinel structure has low electrochemical activity and is not involved in Li insertion/extraction. After the surface modification, it was found that the coverage of the spinel structure did not increase. Further, it was also found out that the Li concentration at the electrode/electrolyte interface increased.
Somekawa, Hidetoshi*; Yamaguchi, Masatake; Osawa, Yoshiaki*; Singh, A.*; Itakura, Mitsuhiro; Tsuru, Tomohito; Mukai, Toshiji*
Philosophical Magazine, 95(8), p.869 - 885, 2015/02
Times Cited Count：23 Percentile：70.58(Materials Science, Multidisciplinary)no abstracts in English
Ebihara, Kenichi; Kaburaki, Hideo; Takai, Kenichi*
Proceedings of 2012 International Hydrogen Conference; Hydrogen-Materials Interactions, p.553 - 561, 2014/02
The crack causing hydrogen embrittlement is observed in steels as the structural material. Accurate evaluation of hydrogen detrapping activation energy, which represents the binding strength between hydrogen atoms and the lattice defects, is crucial to the understanding of the mechanism of hydrogen embrittlement in steels. The Choo and Lee's method, which experimentally evaluates the detrapping energy from the hydrogen thermal desorption profile, should be scrutinized, because this method neglects the hydrogen diffusion in the specimen. By their method, we have evaluated detrapping activation energies from the experimental desorption profiles for pure iron, and also from that simulated by the 1D reaction-diffusion equation. We found that their method underestimates the detrapping energies as the specimen size is large. We also found that this dependence on the specimen size is caused by the degradation of the desorption peak of the detrapping process by the diffusion process.
Ebihara, Kenichi; Kaburaki, Hideo
Suiso Zeika Kenkyu No Kiban Kochiku Chukan Hokokukai Yokoshu, p.27 - 34, 2012/09
The thermal desorption analysis (TDA) is the experimental method to identify hydrogen state, which is necessary for understanding the mechanism of hydrogen embrittlement in steels. From the thermal desorption profile obtained by TDA, the binding energy between hydrogen and defects, which is important for estimating the hydrogen state, can be calculated. Since the desorption profile is influenced by the specimen size and the initial hydrogen state before starting TDA, the understanding of their influence on the desorption profile is necessary. By simulating the desorption profile using the reaction-diffusion equations incorporating the parameters which were corrected by reproducing the experimental profile of martensitic steels, we confirmed that the profile peak becomes broad and the calculated binding energy becomes low when the size is large, and found that two desorption peaks are observed when the non-equilibrium state is used as initial state for the large-size specimen.
Yamaki, Tetsuya; Kobayashi, Misaki*; Asano, Masaharu; Nomura, Kumiko*; Takagi, Shigeharu*; Maekawa, Yasunari; Yoshida, Masaru*
Proceedings of Sadoway 60 Symposium, p.114 - 120, 2010/06
My presentation deals with the application of high-energy heavy ion beams from the cyclotron accelerator of Takasaki Ion Accelerators for Advanced Radiation Application (TIARA), JAEA. Our strategic focus is centered on using nano-scale controllability of the ion-beam processing; the membrane preparation involves (1) the irradiation of commercially-available base polymer films with hundreds of MeV ions, (2) graft polymerization of vinyl monomers into electronically-excited parts along the ion trajectory, called latent tracks, and (3) sulfonation of the graft polymers. Interestingly, the resulting membranes exhibited anisotropic proton transport, i.e., higher conductivity in the thickness direction. According to microscopic observations, this is probably because the columnar electrolyte phase extended, with a width of tens-to-hundreds nanometers, through the membrane.
Yamaki, Tetsuya; Kobayashi, Misaki*; Asano, Masaharu; Yoshida, Masaru; Nomura, Kumiko*; Takagi, Shigeharu*; Maekawa, Yasunari
no journal, ,
Fluoropolymer films were bombarded with swift heavy ions to produce an activated zone along the incident axis. The chemically active species generated in this so-called ion track were used to initiate the grafting of styrene, and the subsequent sulfonation of the graft chains provided the electrolyte membranes with anisotropic proton conductivity in the thickness direction. These membranes were found to have sufficient mechanical strength as well as highly conductive pathways with a cylindroidal shape of tens-to-hundreds nanometer size.
Kobayashi, Misaki*; Yamaki, Tetsuya; Nomura, Kumiko*; Takagi, Shigeharu*; Asano, Masaharu; Yoshida, Masaru; Maekawa, Yasunari
no journal, ,
To realize mass commercialization of fuel cell, many kinds of properties, such as high proton conductivity, low water swelling and high mechanical strength, are required for a polymer electrolyte membrane. Utilizing nano-scale controllability of an ion beam is our strategic way for the preparation of fuel-cell electrolyte membranes. The preparation of membranes involve (1) the irradiation of heavy ions with different masses and energies; (2) the grafting of styrene into electronically-excited region along the ion trajectory called the latent track; (3) sulfonation of the graft chains. According to the FE-SEM and TEM observations, the proton conductive electrolyte part appeared to extend through the membrane thickness with dimensions of tens-to-hundreds nanometers, which agreed with the calculated latent track diameter. Correlations between membrane properties, such as proton conductivity and nanostructure were investigated.
Yamaki, Tetsuya; Asano, Masaharu; Kobayashi, Misaki*; Nomura, Kumiko*; Takagi, Shigeharu*; Maekawa, Yasunari; Yoshida, Masaru
no journal, ,
In order to develop proton-conductive membranes for PEFCs, we have been using high-energy heavy ion beams from the cyclotron accelerator of TIARA. Our strategic focus is centered on using nano-scale controllability of the ion-beam processing; the membrane preparation involves (1) the irradiation of commercially-available base polymer films with MeV ions, (2) graft polymerization of vinyl monomers into electronically-excited parts along the ion trajectory, called latent tracks, and (3) sulfonation of the graft polymers. Interestingly, the resulting membranes exhibited anisotropic proton transport, i.e., higher conductivity in the thickness direction. According to microscopic observations, this is probably because the columnar electrolyte phase extended, with a width of tens-to-hundreds nanometers, through the membrane. Other excellent membrane properties, e.g., sufficient mechanical strength, high dimensional stability, and low gas permeability should be due to such a controlled structure.
Yamaki, Tetsuya; Asano, Masaharu; Kobayashi, Misaki*; Nomura, Kumiko*; Takagi, Shigeharu*; Maekawa, Yasunari; Yoshida, Masaru
no journal, ,
We have been using high-energy heavy ion beams from the cyclotron accelerator of Takasaki Ion Accelerators for Advanced Radiation Application (TIARA), JAEA to develop proton-conductive membranes for PEFCs. Our strategic focus is centered on using nano-scale controllability of the ion-beam processing; the membrane preparation involves (1) the irradiation of commercially-available base polymer films with MeV ions, (2) graft polymerization of vinyl monomers into electronically-excited parts along the ion trajectory, called latent tracks, and (3) sulfonation of the graft polymers. Interestingly, the resulting membranes exhibited anisotropic proton transport, i.e., higher conductivity in the thickness direction. According to microscopic observations, this is probably because the columnar electrolyte phase extended, with a width of tens-to-hundreds nanometers, through the membrane. Other excellent membrane properties, e.g., sufficient mechanical strength, high dimensional stability, and low gas permeability should be due to such a controlled structure.
Yamaki, Tetsuya; Kobayashi, Misaki*; Asano, Masaharu; Nomura, Kumiko*; Takagi, Shigeharu*; Maekawa, Yasunari; Yoshida, Masaru*
no journal, ,
Our presentation deals with the application of high-energy heavy ion beams to the preparation of nano-structure controlled electrolyte membranes. The membrane preparation involves (1) irradiation of commercially-available base polymer films with 100 MeV 
O, 400 MeV 
Fe, or 450 MeV 
Xe, (2) graft polymerization of vinyl monomers into latent tracks, and (3) sulfonation of the graft polymers. The resulting membranes exhibited anisotropic proton transport, i.e., higher conductivity in the through-plane direction. According to microscopic observations, this is probably because the nearly columnar electrolyte phase with a width of tens-to-hundreds nanometers extended through the membrane. Interestingly, our ion irradiation technique would be able to control the nano-structure of proton-conducting pathways in the membranes. Other excellent membrane properties should also be due to such a controlled structure.
Yamaki, Tetsuya; Kobayashi, Misaki*; Asano, Masaharu; Nomura, Kumiko*; Takagi, Shigeharu*; Maekawa, Yasunari; Yoshida, Masaru*
no journal, ,
This study deals with the application of high-energy heavy ion beams from the cyclotron accelerator of Takasaki Ion Accelerators for Advanced Radiation Application (TIARA), JAEA. Our strategic focus is centered on using nano-scale controllability of the ion-beam processing; the membrane preparation involves (1) the irradiation of commercially-available base polymer films with hundreds of MeV ions, (2) graft polymerization of vinyl monomers into electronically-excited parts along the ion trajectory, called latent tracks, and (3) sulfonation of the graft polymers. The resulting membranes exhibited anisotropic proton transport, i.e., higher conductivity in the thickness direction. The through-plane proton conductivity, which is a more direct measurement of the membrane's conductivity and is of interest in an operating fuel cell, was comparable to that of a Nafion112 membrane at the same ion exchange capacity level.
Itakura, Mitsuhiro; Kaburaki, Hideo; Yamaguchi, Masatake
no journal, ,
no abstracts in English
Kaburaki, Hideo; Itakura, Mitsuhiro; Yamaguchi, Masatake
no journal, ,
no abstracts in English
Yamaguchi, Masatake; Tsuru, Tomohito; Itakura, Mitsuhiro; Kaburaki, Hideo
no journal, ,
no abstracts in English
a
screw dislocation in MgItakura, Mitsuhiro; Yamaguchi, Masatake; Kaburaki, Hideo; Tsuru, Tomohito
no journal, ,
The Peierls stress of the prismatic slip in Mg single crystal is order of magnitude higher than that of the basal slip, resulting in highly anisotropic plasticity and low workability. To design Mg-based alloy with an improved workability, it is crucial to identify and model the correct prismatic slip behavior based on the first-principles method. In the present work, the migration pathway between split screw dislocations which are spread on two adjacent basal planes is identified using first-principles method and drag method. The line tension energy of a kink configuration is also calculated based on the lattice Green function method in first-principles calculations.
Suzudo, Tomoaki; Yamaguchi, Masatake; Tsuru, Tomohito
no journal, ,
Ferritic/Martensitic steels are candidate materials for the first wall of fusion devices. One of the concerns of these materials is the embrittlement at grain boundaries (GBs) under irradiation, and a possible cause of the embrittlement is the He segregation at GBs. We investigated the GB dependency of the He embrittlement using empirical potentials and the first principles calculations. We utilized the cohesive energy of GBs, that is, the work needed to separate a GB, as a measure of the embrittlement. First, we calculated the cohesive energy of a low 
GB, using both the first principles calculations and the empirical potentials, and we validated the empirical potentials. Next, we extended the analysis to various GBs. Note that the first principles calculations can be applied only to low GB because of the computational restriction. We found that the loss ratio of the GB strength with the same He concentration on GBs was almost constant over the different GBs.
Yamaguchi, Masatake; Itakura, Mitsuhiro; Kaburaki, Hideo; Tsuru, Tomohito
no journal, ,
no abstracts in English
Yamazaki, Akiyoshi*; Kamiya, Tomihiro; Sato, Takahiro; Mima, Kunioki*; Fujita, Kazuhisa*; Okuda, Chikaaki*; Sawada, Hiroshi*; Saito, Tsohiya*; Gonzales, R.*; Perlado, J. M.*; et al.
no journal, ,
Saito, Tsohiya*; Yamazaki, Akiyoshi*; Kamiya, Tomihiro; Fujita, Kazuhisa*; Mima, Kunioki*; Kato, Yoshiaki*; Iba, Hideki*
no journal, ,
Yamaki, Tetsuya
no journal, ,
Researchers at Japan Atomic Energy Agency (JAEA) have been intensively working on quantum beam technology for the development of proton-conductive membranes for PEMFCs since 2001. My presentation deals with the application of high-energy heavy ion beams from the cyclotron accelerator of Takasaki Ion Accelerators for Advanced Radiation Application (TIARA), JAEA. Our strategic focus is centered on using nano-scale controllability of the ion-beam processing; the membrane preparation involves (1) the irradiation of commercially-available base polymer films with hundreds of MeV ions, (2) graft polymerization of vinyl monomers into electronically-excited parts along the ion trajectory, called latent tracks, and (3) sulfonation of the graft polymers. The resulting membranes were compared with those prepared by the conventional 
-ray-induced grafting in terms of membrane nanostructures, proton conductivity, and other properties.
