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Mechanical properties of sulfide glasses in all-solid-state batteries

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The 75th CerSJ Awards for Academic Achievements in Ceramic Science and Technology: Review
Special Article
published : vol. 131, no. 11, November 2023
Minoru Osada
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Two-dimensional (2D) nanosheets, which possess atomic or molecular thicknesses and infinite lateral lengths, have received increasing attention due to their intriguing physicochemical properties distinct from those of their bulk counterparts. In particular, the discovery of graphene has opened new possibilities for exploring the fascinating properties of 2D nanosheets of other layered and non-layered compounds. 2D inorganic nanosheets (ceramic nanosheets) are important targets in this regard due to their diversity in chemical composition, structure and functionality beyond graphene. Here, we review recent advances in the synthesis, assembly and properties of 2D oxide nanosheets, highlighting emerging functionalities in electronic applications.
The 77th CerSJ Awards for Advancements in Ceramic Science and Technology: Review
Special Article
published : vol. 131, no. 11, November 2023
Yuichi Tominaga
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With the rapid development of electronic device performances, it is crucial to provide an efficient heat removal in electronic devices. For thermal management, ceramic particle/polymer composite materials with high thermal conductivities are of interest. Recently, hexagonal boron nitride (hBN) particles and related composite materials have been intensely studied due to the excellent properties of hBN particles. The shape and orientation of the hBN particles affect the properties of the composite materials because hBN is a plate-like particle and has an anisotropic thermal conductivity. This article provides an overview of powder technologies of hBN particles, such as exfoliation, granulation, and composition with nanofibers, for high thermal conductivities of composite materials. Furthermore, I discuss the fabrication processes and thermal properties of hBN/polymer composite materials potentially applicable in thermal interface materials.
Full Paper
published : vol. 131, no. 11, November 2023
Koichiro Fukuda, Shu Okada, Iori Terao, Atsushi Mineshige, Daisuke Urushihara and Toru Asaka
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The two types of c-axis-aligned polycrystals of lanthanum silicate oxyapatite (LSO) doped with K2O and Al2O3 were prepared by the templated grain growth method with different template/matrix mass ratios of 11.1/88.9 and 5.9/94.1. The template particles, K2O- and F-doped plate-like LSO crystals with developed {001} faces, and the matrix powder, mainly Al2O3-doped LSO, were those used in a previous study with the template/matrix mass ratio of 20.0/80.0. Considering the ionic conductivity and orientation degree of the three types of textured polycrystals, the intermediate mixing ratio of 11.1/88.9 was found to be optimal among the three, with the texture fraction of {0 0 l}apatite being 0.74. Thus, the random grain oriented polycrystal was prepared with the same bulk chemical composition as the control sample. As the temperature increased from 773 to 823 K, the bulk oxide-ion conductivity (σb) of the textured polycrystal increased from 1.04 × 10−3 to 1.71 × 10−3 S cm−1 and the activation energy of conduction (Ea) was 0.61 eV. The σb value of the random grain oriented polycrystal increased steadily from 3.80 × 10−5 to 5.26 × 10−4 S cm−1 with increasing temperature from 773 to 973 K (Ea = 0.92 eV). Comparing the σb values at the same temperatures, the former was 27.5 (773 K) and 21.2 (823 K) times higher than the latter. The chemical formula of the doped LSO in the textured polycrystal was determined from the average composition to be (La9.59K0.090.32)(Si5.50Al0.380.12)O26, where □ denotes vacancies in La and/or Si sites. The major chemical composition of the coexisting interstitial material was estimated to be 29.8 mol % La2O3, 44.9 mol % SiO2, and 25.3 mol % Al2O3. The mole fractions were determined by the lever rule to be 0.9824 for doped LSO and 0.0176 for interstitial material.
Full Paper
published : vol. 131, no. 11, November 2023
Hirosuke Sonomura, Tomoatsu Ozaki, Yasunori Hasegawa, Yoshiaki Sakurai and Masanobu Chiku
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The solvothermal method was used to prepare 0.125 mol % Li3BO3-coated graphite powder as an anode material for an all-solid-state lithium battery. Scanning electron microscopy observations and electron probe microanalysis revealed the Li3BO3 was distributed uniformly on the graphite surface as fine particles and a film. The average crush strength of the coated graphite powder particles was higher than that of the uncoated graphite powder particles, and the standard deviation was lower. An all-solid-state lithium battery with the coated graphite powder showed a slightly higher capacity retention rate than that containing uncoated graphite powder.
Full Paper
published : vol. 131, no. 11, November 2023
Jiefeng Wang, Xiaofeng Yuan, Jun Li, Qiushi Wang, Wentao Xiong and Taiang Song
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After a long time of exploration, the solid-state reaction method is further modified. In the granulation process, 10 % isopropanol is added into ethanol to increase the viscosity. More than that, the green body of the ceramic is placed into the isostatic press and pressed at 200 MPa for 3 min again after being kept in the muffle furnace at 120 °C for 1 h. The modified solid-state reaction method further improves the sintering property of the Na2WO4 ceramic, which increases the dielectric property of the ceramic sample greatly. Besides, the granulation problem, the bubble problem and the problem in demoulding process are solved. The substitution of ethanol and isopropanol for polyvinyl ethanol (PVA) completely avoids the residue of PVA in the ceramic sample and increases the fluidity of the ceramic particles in the granulation process. As a result, the Na2WO4 ceramic can be sintered well at 560 °C with a relative permittivity of 5.82, Q × f value of 131300 GHz and a temperature coefficient of resonant frequency (TCF) value of −56.2 ppm/°C in this work. The modified solid-state reaction method is a good substitute for the conventional solid-state method.
Full Paper
published : vol. 131, no. 11, November 2023
Chihiro Sakai and Yukihito Nagashima
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Quantitative valence analysis of iron included in synthesized glasses has been carried out by using high-resolution X-ray fluorescence (XRF) analyzer which attached the high-resolution curved-double analyzing crystals of Si(220). The measurement results of the standard materials of Fe2+ (FeTiO3) and Fe3+ (Fe2O3) have been carefully compared for the peak analysis of provided high-resolution Fe-Kα profiles. The chemical valences (Fe2+ and Fe3+) of iron component included in the glasses have been quantitatively analyzed on the basis of multiple peak analysis of Fe-Kα (both Fe-Kα1 and Fe-Kα2). The Fe2+/Fe3+ ratio has been calculated for the glasses which were synthesized under the different oxidation–reduction conditions. Additionally, the quantitative valence analysis of sulfur has been also carried out by using high-resolution XRF analyzer which attached the analyzing crystals of Ge(111) in order to clarify the relationships with iron component. Chemical valences (S2− and S6+) of sulfur component were congruent with the chemical valence of iron component. Quantitative valence analysis by high-resolution XRF analysis has large advantages for the sample preparations, the surface analysis and the automated analysis.