Articles
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Mechanochemical activation of metallic lithium for the generation and application of organolithium compounds in air
Here we report a mechanochemical method for the direct generation of organolithium reagents from readily available organic halides and unactivated lithium metal (lithium wire) under bulk-solvent-free conditions. These reactions rapidly generate a diverse array of organolithium compounds at room temperature without special precautions against moisture and without temperature control.
Kondo Keisuke, Koji Kubota, and Hajime Ito
The Detail Matters: Unveiling Overlooked Parameters in the Mechanochemical Synthesis of Solid Electrolytes
“Simply mixing the reagents by hand for a short time in a mortar and pestle before mechanochemical synthesis dramatically improves the performance of the solid electrolyte.
Hand mixing changes the crystallization behavior, improving the ionic conductivity of the solid electrolyte by up to an order of magnitude.
This discovery will accelerate the search for efficient and logical new electrolyte materials, and ultimately the development of all-solid-state batteries.”Abdulkadir Kızılaslan, Mustafa Çelik, Yuta Fujii, Zheng Huang, Chikako Moriyoshi, Shogo Kawaguchi, Satoshi Hiroi, Koji Ohara, Mariko Ando, Kiyoharu Tadanaga, Saneyuki Ohno, and Akira Miura
Imaging valley-vortex edge modes in a phononic crystal at ultrahigh frequencies
We perform optical measurements and numerical simulations of guided phonon propagation in novel topological phononic crystal structures at ultrahigh frequencies. The structures support valley-polarized states that exhibit an energy vortex nature and propagate with high efficiency at domain boundaries because backscattering is suppressed due to conservation of time reversal symmetry. We extract frequency- and time-resolved spatial mode patterns and -space images, together with dispersion relations. We investigate the conditions required for robust propagation along interfaces and thereby observe very high efficiency waveguiding.
Paul H. Otsuka, Motonobu Tomoda, Daiki Hatanaka, Hiroshi Yamaguchi, Kenji Tsuruta, and Osamu Matsuda
Pore properties and CO₂ adsorption performance of activated carbon prepared from various carbonaceous materials
The production of activated carbon using biomass and coal as carbon sources, melamine as a nitrogen source, and K₂CO₃ as a chemical activator revealed that the lower carbon content and lower ash content of the carbon source resulted in better pore development, and that the surface area and micropore volume of activated carbon affected the CO₂ adsorption capacity. It was also shown that the optimal micropore size for CO₂ adsorption is 0.5 to 1.2 nm. These results are expected to lead to the establishment of production guidelines for activated carbon with high CO₂ adsorption capacity.
Yuuki Mochizuki, Javzandolgor Bud, Enkhsaruul Byambajav, and Naoto Tsubouchi
Selective separation of Li, Ni, Co and Mn from model spent Li ion battery cathode materials by dry processing using the combination of chlorination and oxidation
The present group has recently developed a technology to selectively recover valuable metals (Li, Ni, Co and Mn) from used lithium-ion battery cathode materials (LiNiO₂, LiCoO₂, LiMn₂O₄, and their composite composition). Specifically, we found that Li, Ni, Co and Mn can be selectively separated from LiNiO₂, LiCoO₂, and LiMn₂O₄ by chlorination up to 600℃ followed by air oxidation up to 1300℃. This research paper was selected as a Key Scientific Article by the selection committee of Advances in Engineering, Canada, and is highly evaluated.
Recovery of phosphate from carbonized sewage sludge by chlorination
The present research group has recently found a method to recover phosphorus, which is called “biological and technical nutrient”, from sewage sludge as phosphorus chloride forms. Specifically, we have developed a simple sewage sludge recycling technology that first carbonizes sewage sludge to improve handling, then chlorinates the resulting carbonized material at 500℃, and finally separates phosphorus chloride species and impurities by a cooled deposition method. This method can be applied to sewage sludge incineration ash, livestock manure, steelmaking slag, etc.
Investigation of Single Ammonia Droplet Evaporation Characteristics Under High Temperature and Pressure Conditions
Ammonia is a promising alternative fuel for significantly reducing CO₂ emissions. However, to utilize it efficiently, it is necessary to develop technologies that enable direct spray combustion of liquid ammonia. In this study, we clarified—for the first time in the world—the evaporation characteristics of ammonia droplets under high-temperature and high-pressure conditions. Furthermore, we obtained essential droplet evaporation data necessary for the development of ammonia spray combustion technology.
Leang So Khuong, Nozomu Hashimoto, Yu Ito, Nobuto Nakamichi, Yusuke Konno, and Osamu Fujita
Unveiling the origin of diffusion suppression of hydrogen isotopes at the α-Al₂O₃(0001)/α-Cr₂O₃(0001) interfaces
Hydrogen in metallic materials causes degradation known as hydrogen embrittlement, which renders the materials brittle. Therefore, to promote the use of hydrogen energy in applications such as fuel cells and nuclear fusion reactors, strategies to prevent hydrogen permeation into structural materials are essential. In this study, we elucidated the mechanism by which coating multiple layers of different ceramic films on metal surfaces, which serve as hydrogen permeation barriers, can more effectively suppress hydrogen permeation than single-layer ceramic films. This research can contribute to extending the service life of metallic materials in a hydrogen environment.
Yuji Kunisada, Ryotaro Sano, and Norihito Sakaguchi
International Journal of Hydrogen Energy, Volume 97, Pages 1327-1334
Effect of Wet−dry Cycles and Water-to-cement Ratios on Cement Paste Carbonation
Cement production consumes a significant amount of energy and releases CO₂ emissions, while concrete waste can potentially reabsorb CO₂. This study examined the effect of relative humidity (especially wet-dry cycles) on the carbonation of hardened cement pastes. Wet–dry cycles increased porosity and caused the decomposition of calcium silicate hydrate (C-S-H) through shrinkage and deformation during drying. As a result, the highest CO₂ absorption in the wet-dry cycle sample was twice that of the constant RH. Additionally, the amount of CO₂ captured during the 28-day wet-dry cycle accounted for about 17% of the annual CO₂ emissions from cement production.
Zhiwei Zhao, Dayoung Oh (researchmap.jp, researchgate.net, scholar.google.com), Ryoma Kitagaki, Tianlong Zheng, and Ippei Maruyama