A5073388529- Advancements in Battery Materials
- Electron and X-Ray Spectroscopy Techniques
- X-ray Spectroscopy and Fluorescence Analysis
- Spectroscopy and Quantum Chemical Studies
- Animal Behavior and Welfare Studies
- X-ray Diffraction in Crystallography
- Advanced Battery Materials and Technologies
- Electrochemical Analysis and Applications
- Electrocatalysts for Energy Conversion
- Surfactants and Colloidal Systems
- Advanced Battery Technologies Research
- Advanced X-ray Imaging Techniques
- Rare-earth and actinide compounds
- Human-Animal Interaction Studies
- Fuel Cells and Related Materials
- Radioactive element chemistry and processing
- Magnetic and transport properties of perovskites and related materials
- Advancements in Solid Oxide Fuel Cells
- Iron oxide chemistry and applications
- Animal Nutrition and Physiology
- Photochemistry and Electron Transfer Studies
- Catalytic Processes in Materials Science
- Chemical and Physical Properties in Aqueous Solutions
- Phase-change materials and chalcogenides
- Extraction and Separation Processes
Hiroshima University
2000-2025
Japan Atomic Energy Agency
2007-2024
Japan Synchrotron Radiation Research Institute
2011-2023
Nissan (Japan)
2017-2020
Naval Hospital Yokosuka Japan
2017-2019
Nissan (United Kingdom)
2017-2018
Kyoto University
2011-2018
SPring-8
2006-2016
Japan Society
2012-2015
Toyama College
2012
The limit to which the phase change memory material Ge2Sb2Te5 can be scaled toward smallest possible cell is investigated using structural and optical methodologies. encapsulation surrounding has an increasingly dominant effect on material's ability phase, a profound increase in crystallization temperature observed when layer less than 6 nm thick. We have found that increased originates from compressive stress exerted material. By minimizing stress, we maintained bulk films just 2
The phase transition between LiFePO4 and FePO4 during nonequilibrium battery operation was tracked in real time using time-resolved X-ray diffraction. In conjunction with increasing current density, a metastable crystal appears addition to the thermodynamically stable phases. gradually diminishes under open-circuit conditions following electrochemical cycling. We propose path that passes through posit new phase's role decreasing nucleation energy, accounting for excellent rate capability of...
Surface analysis: In situ total-reflection fluorescence X-ray absorption spectroscopy showed that reduction of cobalt at the surface a LiCoO2 electrode occurs by contact with liquid electrolyte. An irreversible behavior was observed during first charge/discharge process whereas bulk material reversible behavior. This Co is an initial deterioration.
On the Pt/C cathode in a fuel cell, dynamic surface events were investigated by novel X-ray absorption techniques (see Fourier transform for oxidation process, 0.4→1.0 V). Evidence Pt dissolution at was found, and reaction kinetics of electron-transfer processes, as well redox structural changes significant time lag between events, observed first under operando conditions. Supporting information this article is available on WWW http://www.wiley-vch.de/contents/jc_2002/2007/z604732_s.pdf or...
Abstract Crystallization of an amorphous solid is usually accompanied by a significant change transport properties, such as increase in thermal and electrical conductivity. This fact underlines the importance crystalline order for charge heat. Phase‐change materials, however, reveal remarkably low conductivity state. The small this upon crystallization points to unique lattice properties. present investigation reveals that properties state phase‐change materials show remarkable differences...
Vertical profiles of iodine-131 and cesium-137 emitted from the Fukushima Daiichi Nuclear Power Station were determined in soil core samples collected prefecture. The showed that more than 76% radionuclides retained within 5 cm surface. Leaching experiments cesium was strongly bound to particles which could not be leached with 2 M HCl, while 40% iodine incorporated into humic substances.
Transient states of phase transition in LiFePO4/FePO4 for lithium ion battery positive electrodes are investigated by time-resolved measurements. To directly detect changes electronic and crystal structures under operation, situ X-ray absorption diffraction measurements performed, respectively. The fraction change estimated the iron valence is similar to electrochemically expected change. transient lattice constant during two reaction clearly observed measurement. nonequilibrium extraction...
液液界面（油水界面）における構造解析法として，X-ray Absorption fine structure（XAFS）法を用いた手法が新しく開発されている。この方法を用いることにより，界面に存在する化学種を直接測定することにより，濃度や化学状態，分子配向，溶媒和構造などの情報をin situで得ることができる。本稿では，臭化物イオンや亜鉛イオンなどを含む界面化学種への応用について解説する。
Depth-resolved X-ray absorption spectroscopy (DR-XAS) measurements were performed for the direct observation of chemical state and local structure at LiCoO2 electrode–solid electrolyte model interface, which can contribute towards enhancement power density in all solid-state lithium batteries. The charge transfer resistance, measured by AC impedance spectroscopy, interface decreased with introduction a NbO2 interlayer while resistance increased ZrO2 MoO2 interlayers. Using DR-XAS depth...
Adsorption reactions of various cations on clay minerals have different effects their environmental behaviors depending the molecular-scale adsorption structure. Some form outer-sphere complexes via hydration, while others create inner-sphere through dehydration. This preference dictates impact. However, factors controlling these complex formations remain unclear. Furthermore, research preferences radium (Ra) is lacking. Thus, this study conducted first EXAFS Ra
An x-ray absorption fine-structure (XAFS) spectroscopy beamline, BL01B1, was installed at a bending magnet source SPring-8 and has been open to users since October 1997.It designed for XAFS experiments covering wide energy range.Position tables automatical control programs were established adjust the optics achieve performance of beamline under each experimental condition.This enabled conventional measurements be made with good data quality from 4.5 110 keV.
Subnanosecond time-resolved x-ray absorption measurements have been used to probe dynamical changes in the local structure about Ge atoms phase-change alloy ${\text{Ge}}_{2}{\text{Sb}}_{2}{\text{Te}}_{5}$ during optical recording (amorphization) process using an pump and technique examine reversible phase transition from metastable crystalline amorphous phase. We provide unambiguous evidence that amorphization does not proceed via molten state but is a photoassisted process. argue...
In situ chemical immobilization is a practical remediation technology for metal‐contaminated soils because of its capability to reduce cost and environmental impacts. We assessed the effects poultry waste amendment plant growth ( Panicum maximum Jacq.) on Pb speciation enzyme activities in shooting range soils. Soil contaminated with was obtained from top 20 cm range. To evaluate mobility soil profile treated plants immobilizing amendment, we used large columns filled Pb‐contaminated (0–20...
Time-resolved X-ray reflectivity measurements for lysozyme (LSZ) adsorbed at an air/water interface were performed to study the mechanism of adsorption-induced protein unfolding. The time dependence density profile revealed that molecular conformation changed significantly during adsorption. Taking into account previous work using Fourier transform infrared (FTIR) spectroscopy, we propose LSZ molecules initially on have a flat unfolded structure, forming antiparallel beta-sheets as result...
The presence of ionic multilayers at the free surface an liquid, trioctylmethylammonium bis(nonafluorobutanesulfonyl)amide ([TOMA(+)][C(4)C(4)N(-)]), extending into bulk from to depth approximately 60 A has been probed by x-ray reflectivity measurements. versus momentum transfer (Q) plot shows a broad peak Q 0.4 A(-1), implying layers [TOMA(+)][C(4)C(4)N(-)] surface. analysis using model fittings revealed that least four are formed with interlayer distance 16 A. TOMA(+) and C(4)C(4)N(-)...
Surface modification effects on interfacial reaction for zirconia (ZrO2) coated lithium cobalt oxide (LiCoO2) are studied. ZrO2-coated LiCoO2 thin-film electrodes prepared by a pulsed laser deposition with different preparation periods. Cyclic voltammetry measurements clearly show that cycle performance and high-potential durability improved the ZrO2 coating. AC impedance spectroscopy reveals there two types of resistance associated coating; one is charge transfer which depends...
Surface coating on lithium‐ion battery cathodes improves their durability at high potentials, which is a well‐known practical application. However, the mechanism still unclear because influences electrode/electrolyte interface few nanometer‐scale and direct observation of under real operating conditions challenging. This study reveals surface effect by using in operando X‐ray absorption spectroscopy (XAS) well‐defined MgO‐coated LiCoO 2 thin‐film electrodes prepared via pulsed laser...
For the further development of lithium-ion batteries, improvement their cyclic performance is crucial. However, mechanism underlying deterioration battery not fully understood. We investigated effects electronic structure at electrode/electrolyte interface on cathode materials via in situ total-reflection fluorescence X-ray absorption spectroscopy. In a LiCoO2 thin-film electrode that exhibits gradual upon subsequent Li ion extractions and insertions (cycling), reduction Co ions was observed...
We have developed a quick-scanning x-ray absorption fine structure (QXAFS) system and installed it at the recently constructed synchrotron radiation beamline BL33XU SPring-8. Rapid acquisition of high-quality QXAFS data was realized by combining servo-motor-driven Si channel-cut monochromator with tapered undulator. Two tandemly aligned monochromators Si(111) Si(220) crystals covered energy ranges 4.0–28.2 keV 6.6–46.0 keV, respectively. The allows users to adjust instantly scans, starting...
Lifetimes of lithium-ion batteries are often affected by deterioration positive electrodes. It is well-known that the electrodes can be reduced using electrolyte additives; however, mechanism underlying this cyclability improvement needs to clarified. In study, we investigate electronic structure at electrode/electrolyte interface in situ total-reflection fluorescence X-ray absorption spectroscopy elucidate a LiCoO2 electrode upon addition vinylene carbonate (VC) electrolyte. The results...
Here, we report remarkable oxygen evolution reaction (OER) catalytic activity of brownmillerite (BM)-type Ca2 FeCoO5 . The OER this oxide is comparable to or beyond those the state-of-the-art perovskite (PV)-catalyst Ba0.5 Sr0.5 Co0.8 Fe0.2 O3-δ (BSCF) and a precious-metal catalyst RuO2 , emphasizing importance characteristic BM structure with multiple coordination environments transition metal (TM) species. Also, clearly advantageous in terms expense/laboriousness material synthesis. These...