Search

Your search keyword '"Sato, Kazunori"' showing total 1,144 results
Start Over Author "Sato, Kazunori"
1,144 results on '"Sato, Kazunori"'

201. Pressure-dependent multiplet-excitation energies of α-Al2O3:Cr3+by the first-principles method

Author

Saito, Harutaka, Suzuki, Katsuhiro, Sato, Kazunori, and Kotani, Takao

Abstract

We apply a method [Phys. Rev. B108, 035141 (2023)], which can treat the multiplet excitations in the first-principles method, to a typical pressure indicator α-Al2O3:Cr3+. After optimizing the crystal structure under hydrostatic pressure from 0.0 to 35.0 GPa in the usual first-prinicple calculations, we obtain the multiplet energies in the method. That is, we conduct the exact diagonalization of the crystal-field model Hamiltonian which is directly determined based on the result of the quasiparticle self-consistent GW method. Our method has no parameters by hand. The calculated pressure dependences of the excitation energies agree well with those of experiments.

Published
2024
Full Text
View/download PDF

203. Two-dimensional NaxSiS as a promising anode material for rechargeable sodium-based batteries: ab initio material design.

Author

Pham, Thi Dung, Luong, Huu Duc, Sato, Kazunori, Shibutani, Yoji, and Dinh, Van An

Abstract

The rapidly rising demand for energy storage systems presents an imperative need to develop sodium-ion batteries with high energy density, high conductivity, and low barrier energy. In this work, we present a Density Functional study on the properties of two-dimensional NaxSiS as a promising anode material for rechargeable sodium-ion batteries. Energetically stable structures of Na-adsorbed silicene sulfide NaxSiS with various Na contents were explored. It is found that the adsorption energy of a Na atom is higher than −0.4 eV and it decreases with increasing Na content. The electronic structure of pristine silicene sulfide shows semiconductor behaviour with a bandgap of 0.99 eV, while the Na-adsorbed SiS exhibits metallic characteristics. The highest theoretical capacity of 187.2 mA h g−1, which is higher than that of well-known two dimensional materials, is found in the fully intercalated phase of SiS Na0.5SiS which corresponds to per side layer. Furthermore, Na ions can diffuse along two typical pathways on the surface of SiS with a small barrier of 183 meV which is much smaller than that of the two dimensional LixSiS, NaxTiS2, and NaxMoS2. All these characteristics suggest that silicene sulfide SiS can be expected to be a promising anode material for sodium ion batteries. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

225. Electrochemical and Microstructure Characterization of (Ni0.5Co0.5)-MgO-TiO2-YSZ Cermet Anode

Author

Wichapun Weerapakkaroon, Wah Tzu Teoh, and Sato Kazunori

Subjects
Materials science, Metallurgy, Cermet, Microstructure, Electrochemistry, Yttria-stabilized zirconia, Anode, Characterization (materials science)
Abstract

The Ni0.5Co0.5-MgO-TiO2-(8 mol%Y2O3-ZrO2) (NCMTO-YSZ) cermet anode showed a higher cell performance than NiO-YSZ and Ni0.5Co0.5O-YSZ cermet anodes under dry CH4 fuel, while the cell performance between Ni0.5Co0.5O-YSZ and NCMTO-YSZ cermet anodes were not significantly different under H2 fuel. NCMTO-YSZ decreased the anodic overvoltage and polarization resistance because Ni0.5Co0.5-MgO solid solution existing in the cermet anode contributes to increase active sites for the electrochemical oxidation of methane. The enhancement of the direct methane oxidation was caused by the microstructure improvement owing to MgO and a small amount of TiO2 solid solution.

Published
2008

Catalog

Books, media, physical & digital resources
See catalog results