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Hirano, Tatsumi*; Maeda, Takehiro*; Murata, Tetsuyuki*; Yamamoto, Takahiro*; Matsubara, Eiichiro*; Shobu, Takahisa; Shiro, Ayumi*; Yasuda, Ryo*; Takamatsu, Daiko*
SPring-8/SACLA Riyo Kenkyu Seikashu (Internet), 11(5), p.345 - 353, 2023/10
no abstracts in English
Hirano, Tatsumi*; Maeda, Takehiro*; Murata, Tetsuyuki*; Yamaki, Takahiro*; Matsubara, Eiichiro*; Shobu, Takahisa; Shiro, Ayumi*; Yasuda, Ryo*; Takamatsu, Daiko*
SPring-8/SACLA Riyo Kenkyu Seikashu (Internet), 11(1), p.49 - 57, 2023/02
Aoyagi, Takuya*; Kohara, Shinji*; Naito, Takashi*; Onodera, Yohei*; Kodama, Motomune*; Onodera, Taiga*; Takamatsu, Daiko*; Tahara, Shuta*; Sataka, Osami*; Miyake, Tatsuya*; et al.
Scientific Reports (Internet), 10, p.7178_1 - 7178_12, 2020/04
Times Cited Count:14 Percentile:41.41(Multidisciplinary Sciences)Understanding the structure-property relationship of glass material is still challenging due to a lack of periodicity in disordered materials. Here, we report the properties and atomic structure of vanadium phosphate glasses characterized by reverse Monte Carlo modelling based on neutron/synchrotron X-ray diffraction and EXAFS data, supplemented by Raman and NMR spectroscopy. In vanadium-rich glass, the water durability, thermal stability and hardness improve as the amount of P
O
increases, and the network former of the glass changes from VO
polyhedra to the interplay between VO
polyhedra and PO
tetrahedra. We find for the first time that the coordination number of oxygen atoms around a V
is four, which is an unusually small coordination number, and plays an important role for water durability, thermal stability and hardness. Furthermore, we show that the similarity between glass and crystal beyond the nearest neighbor distance is important for glass properties. These results demonstrate that controlling the oxygen coordination and valence of the network-forming cation is necessary for designing the properties of glass.
Ni
Mn
Co
O
in a lithium-ion batteryKonishi, Hiroaki*; Hirano, Tatsumi*; Takamatsu, Daiko*; Gunji, Akira*; Feng, X.*; Furutsuki, Sho*; Okumura, Takafumi*; Terada, Shohei*; Tamura, Kazuhisa
Journal of Solid State Chemistry, 262, p.294 - 300, 2018/06
Times Cited Count:10 Percentile:44.75(Chemistry, Inorganic & Nuclear)The potential in each state of charge (SOC) during charging of Li
Ni
Mn
Co
O
is higher than that during discharging. To clarify the effect of chargedischarge operating conditions on the electrochemical reaction, Li
Ni
Mn
Co
O
was charged and discharged under various charge-discharge operating ranges, and OCP, crystal structure, and oxidation states of the ransition metals were evaluated by electrochemical measurement, XRD, and XAFS. These results indicate that OCP, lattice parameters, and oxidation states of the transition metals of Li
Ni
Mn
Co
O
in each SOC are not constant. The XRD results indicate that two phases, namely, LiNi
Mn
Co
O
-like and Li
MnO
-like, exist in Li
Ni
Mn
Co
O
.
Ni
Mn
Co
O
used for lithium ion batteriesKonishi, Hiroaki*; Hirano, Tatsumi*; Takamatsu, Daiko*; Gunji, Akira*; Feng, X.*; Furutsuki, Sho*; Okumura, Takafumi*; Terada, Shohei*; Tamura, Kazuhisa
Journal of Solid State Chemistry, 258, p.225 - 231, 2018/02
Times Cited Count:9 Percentile:40.80(Chemistry, Inorganic & Nuclear)Li
Ni
Mn
Co
O
is known as one of the cathode electrode material for Li ion batteries and its structure during charge and discharge process was investigated using electrochemical method and X-ray diffraction. It was found that in the charge process the structure changes in the order of Li
MnO
, LiNi
Mn
Co
O
, and Li
MnO
. On the other hand, in the discharge process, the structure changes in the order of Li
MnO
and LiNi
Mn
Co
O
.