Crystal-Like Atomic Arrangement and Optical Properties of 25La2O3-75MoO3 Binary Glasses Composed of Isolated MoO42.

Transparent and brown La2O3-MoO3 binary glasses were prepared in bulk form using a levitation technique. The glass-forming range was limited, with the primary composition being approximately 25 mol % La2O3. The 25La2O3-75MoO3 glass exhibited a clear crystallization at 546 °C, while determining its glass transition temperature was difficult. Notably, despite its amorphous nature, the glass possessed a density and packing density comparable to those of crystalline La2Mo3O12. X-ray absorption fine structure and Raman scattering analyses revealed that the glass structure closely resembles La2Mo3O12 due to the presence of isolated MoO42- units, whereas disordered atomic arrangement around La atoms was confirmed. The glass demonstrated transparency ranging from 378 to 5500 nm, and the refractive index at 1.0 µm was estimated to be 2.0. The optical bandgap energy was 3.46 eV, which was slightly smaller than that of La2Mo3O12. Additionally, the glass displayed a transparent region ranging from 6.5 to 8.0 µm. This occurrence results from the decreased diversity of MoOn units and connectivity of Mo-O-Mo, which resulted in the reduced overlap of multiphonon absorption. This glass formation, with its departure from conventional glass-forming rules, resulted in distinctive glasses with crystal-like atomic arrangements.

Improvement of the rate capability of all-solid-state cells with Fe-based polysulfide positive electrode materials by modifying the microstructure.

We successfully prepared an Fe- and Li-containing polysulfide positive electrode material (Li8FeS5-Li2FeS2 composite) that shows a high specific capacity (>500 mA h g-1) with improved rate capability in all-solid-state cells. High-resolution TEM analysis indicated the coexistence of small crystallites of high-conductivity Li2FeS2 and FeS, as well as low-crystallinity Li2S, in the composite, and this microstructure is responsible for the improved battery performance.

Kinetic analysis of silicon-lithium alloying reaction in silicon single crystal using soft X-ray absorption spectroscopy.

Silicon has been considered to be one of the most promising anode active materials for next-generation lithium-ion batteries due to its large theoretical capacity (4200 mA h g-1, Li22Si5). However, silicon anodes suffer from degradation due to large volume expansion and contraction. To control the ideal particle morphology, an experimental method is required to analyze anisotropic diffusion and surface reaction phenomena. This study investigates the anisotropy of the silicon-lithium alloying reaction using electrochemical measurements and Si K-edge X-ray absorption spectroscopy on silicon single crystals. During the electrochemical reduction process in lithium-ion battery systems, the continuous formation of solid electrolyte interphase (SEI) films prevents the achievement of steady-state conditions. Instead, the physical contact between silicon single crystals and lithium metals can prevent the effect of SEI formation. The apparent diffusion coefficient and the surface reaction coefficient are determined from the progress of the alloying reaction analyzed by X-ray absorption spectroscopy. While the apparent diffusion coefficients show no clear anisotropy, the apparent surface reaction coefficient of Si (100) is more significant than that of Si (111). This finding indicates that the surface reaction of silicon governs the anisotropy of practical lithium alloying reaction for silicon anodes.

Degradation of Lignin by Infrared Free Electron Laser.

Lignin monomers have attracted attention as functional materials for various industrial uses. However, it is challenging to obtain these monomers by degrading polymerized lignin due to the rigid ether linkage between the aromatic rings. Here, we propose a novel approach based on molecular vibrational excitation using infrared free electron laser (IR-FEL) for the degradation of lignin. The IR-FEL is an accelerator-based pico-second pulse laser, and commercially available powdered lignin was irradiated by the IR-FEL under atmospheric conditions. Synchrotron-radiation infrared microspectroscopy analysis showed that the absorption intensities at 1050 cm-1, 1140 cm-1, and 3400 cm-1 were largely decreased alongside decolorization. Electrospray ionization mass chromatography analysis showed that coumaryl alcohol was more abundant and a mass peak corresponding to hydrated coniferyl alcohol was detected after irradiation at 2.9 µm (νO-H) compared to the original lignin. Interestingly, a mass peak corresponding to vanillic acid appeared after irradiation at 7.1 µm (νC=C and νC-C), which was supported by our two-dimensional nuclear magnetic resonance spectroscopy analysis. Therefore, it seems that partial depolymerization of lignin can be induced by IR-FEL irradiation in a wavelength-dependent manner.

Elucidating Influence of Mg- and Cu-Doping on Electrochemical Properties of O3-Nax [Fe,Mn]O2 for Na-Ion Batteries.

Although O3-NaFe1/2 Mn1/2 O2 delivers a large capacity of over 150 mAh g-1 in an aprotic Na cell, its moist-air stability and cycle stability are unsatisfactory for practical use. Slightly Na-deficient O3-Na5/6 Fe1/2 Mn1/2 O2 (O3-Na5/6 FeMn) and O3-Na5/6 Fe1/3 Mn1/2 Me1/6 O2 (Me = Mg or Cu, O3-FeMnMe) are newly synthesized. The Cu and Mg doping provides higher moist-air stability. O3-Na5/6 FeMn, O3-FeMnCu, and O3-FeMnMg deliver first discharge capacities of 193, 176, and 196 mAh g-1 , respectively. Despite partial replacement of Fe with redox inactive Mg, oxide ions in O3-FeMnMg participate in the redox reaction more apparently than O3-Na5/6 FeMn. X-ray diffraction studies unveil the formation of a P-O intergrowth phase during charging up to >4.0 V.

Irradiation effect of a submillimeter wave from 420†GHz gyrotron on amyloid peptides in vitro.

On using the far-infrared radiation system, whether the irradiation effect is thermal or non-thermal is controversial. We irradiated amyloid peptides that are causal factors for amyloidosis by using a submillimeter wave from 420 GHz gyrotron. Fluorescence reagent assay, optical and electron microscopies, and synchrotron-radiation infrared microscopy showed that the irradiation increased the fibrous conformation of peptides at room temperature for 30 min. The temperature increase on the sample was only below 5 K, and a simple heating up to 318 K hardly induced the fibril formation. Therefore, the amyloid aggregation was driven by the far-infrared radiation with little thermal effect.

Improved Non-Grignard Electrolyte Based on Magnesium Borate Trichloride for Rechargeable Magnesium Batteries.

The high anodic stability of electrolytes for rechargeable magnesium batteries enables the use of new positive electrodes, which can contribute to an increase in energy density. In this study, novel Ph3COMgCl-, Ph3SiOMgCl-, and B(OMgCl)3-based electrolytes were prepared with AlCl3 in triglyme. The Ph3COMgCl-based electrolyte showed anodic stability over 3.0 V vs. Mg but was chemically unstable, whereas the Ph3SiOMgCl-based electrolyte was chemically stable but featured lower anodic stability than the Ph3COMgCl-based electrolyte. Advantageously, the B(OMgCl)3-based electrolyte showed both anodic stability over 3.0 V vs. Mg (possibly due to the Lewis acidic nature of B in B(OMgCl)3) and chemical stability (possibly due to the hard acid character of B(OMgCl)3). B(OMgCl)3, which was prepared by reacting boric acid with a Grignard reagent, was characterized by nuclear magnetic resonance (NMR) spectroscopy, Fourier-transform infrared spectroscopy (FTIR), and X-ray absorption spectroscopy (XAS). The above analyses showed that B(OMgCl)3 has a complex structure featuring coordinated tetrahydrofuran molecules. 27Al NMR spectroscopy and Al K-edge XAS showed that when B(OMgCl)3 was present in the electrolyte, AlCl3 and AlCl2+ species were converted to AlCl4-. Mg K-edge XAS showed that the Mg species in B(OMgCl)3-based electrolytes are electrochemically positive. As a rechargeable magnesium battery, the full cell using the B(OMgCl)3-based electrolyte and a Mo6S8 Chevrel phase cathode showed stable charge-discharge cycles. Thus, B(OMgCl)3-based electrolytes, the anodic stability of which can be increased to ~3 V by the use of appropriate battery materials, are well suited for the development of practical Mg battery cathodes.

Dissociation of ß-Sheet Stacking of Amyloid ß Fibrils by Irradiation of Intense, Short-Pulsed Mid-infrared Laser.

Structure of amyloid ß (Aß) fibrils is rigidly stacked by ß-sheet conformation, and the fibril state of Aß is profoundly related to pathogenesis of Alzheimer's disease (AD). Although mid-infrared light has been used for various biological researches, it has not yet been known whether the infrared light changes the fibril structure of Aß. In this study, we tested the effect of irradiation of intense mid-infrared light from a free-electron laser (FEL) targeting the amide bond on the reduction of ß-sheet content in Aß fibrils. The FEL reduced entire contents of proteins exhibiting ß-sheet structure in brain sections from AD model mice, as shown by synchrotron-radiation infrared microscopy analysis. Since Aß1-42 fibril absorbed a considerable FEL energy at amide I band (6.17 µm), we irradiated the FEL at 6.17 µm and found that ß-sheet content of naked Aß1-42 fibril was decreased using infrared microscopic analysis. Consistent with the decrease in the ß-sheet content, Congo-red signal is decreased after the irradiation to Aß1-42 fibril. Furthermore, electron microscopy analysis revealed that morphologies of the fibril and proto-fibril were largely changed after the irradiation. Thus, mid-infrared light dissociates ß-sheet structure of Aß fibrils, which justifies exploration of possible laser-based therapy for AD.

Application of mid-infrared free-electron laser tuned to amide bands for dissociation of aggregate structure of protein.

A mid-infrared free-electron laser (FEL) is a linearly polarized, high-peak powered pulse laser with tunable wavelength within the mid-infrared absorption region. It was recently found that pathogenic amyloid fibrils could be partially dissociated to the monomer form by the irradiation of the FEL targeting the amide I band (C=O stretching vibration), amide II band (N-H bending vibration) and amide III band (C-N stretching vibration). In this study, the irradiation effect of the FEL on keratin aggregate was tested as another model to demonstrate an applicability of the FEL for dissociation of protein aggregates. Synchrotron radiation infrared microscopy analysis showed that the α-helix content in the aggregate structure decreased to almost the same level as that in the monomer state after FEL irradiation tuned to 6.06 µm (amide I band). Both irradiations at 6.51 µm (amide II band) and 8.06 µm (amide III band) also decreased the content of the aggregate but to a lesser extent than for the irradiation at the amide I band. On the contrary, the irradiation tuned to 5.6 µm (non-absorbance region) changed little the secondary structure of the aggregate. Scanning-electron microscopy observation at the submicrometer order showed that the angular solid of the aggregate was converted to non-ordered fragments by the irradiation at each amide band, while the aggregate was hardly deformed by the irradiation at 5.6 µm. These results demonstrate that the amide-specific irradiation by the FEL was effective for dissociation of the protein aggregate to the monomer form.