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A solid-electrolyte interphase (SEI) is widely recognized to improve the safety and durability of lithium ion batteries. In this work, we investigate the structure and chemistry of the carbon elect...

Comprehensive analyses were performed using neutron reflectivity and hard X-ray photoelectron spectroscopy to understand the structure and composition of the solid electrolyte interphase (SEI) layer during charge-discharge processes and because of the addition of lithium bis(oxalate)borate (LiBOB) to improve the battery performance. The chemical composition of the SEI was assessed using these methods, and the amount of Li

Introduction A solid-electrolyte interphase (SEI) is known to play a significant role on safety and durability of lithium ion batteries (LIBs). Here, the chemical composition of SEI has been usually determined with an ex-situ X-ray photoelectron spectroscopic analysis technique. However, there are few reports on the structural properties of SEI, such as thickness and density, and their variation with cyclic charge and discharge reactions, because of the difficulty for observing SEI with an in-situ manner. This means that we will never reach deep understanding of “alive” SEI and its formation mechanism through the work on “dead” SEI with ex-situ analytical techniques. Therefore, we have started to use neutron reflectivity (NR), as NR is a powerful technique for estimating thickness and density of an interface between solid and liquid. Furthermore, since the interfacial reaction is expected to occur within a few nanometer-thickness from the initial boundary between electrode and electrolyte, we naturally need a NR technique with more precise spatial resolution for such purpose than the past NRs. Fortunately, Japan Proton Accelerator Research Complex (J-PARC) is one of the most intense spallation neutron source, leading to the highest depth resolution of NR in the world. Here, we report the first operando measurement of the SEI formation during the initial charge, i.e. lithiation reaction in the carbon electrode of LIB using a combination of in situ NR and electrochemical analyses [1]. Experimental As an electrode for NR measurements, a carbon/titanium multi-layer film was deposited on a silicon substrate by a magnetron sputtering technique (Fig. 1). Here, the titanium layer is necessary to increase adhesive force between the carbon electrode and Si substrate. In a special electrochemical cell for in-situ NR measurements, the carbon/titanium film was a working electrode, a lithium foil was a counter electrode, 1 mol/L LiPF6 in a 1:1 (v/v) ratio of ethylene carbonate and diethyl carbonate was an electrolyte, and a microporous polyethylene membrane was a separator. Cyclic voltammetry (CV) was performed at a slow sweep rate of 0.2 mV/s between 3.3 and 0.05 V. In situ NR measurements were performed during the repeated charge and discharge, i.e. lithiation and delithiation cycles on the surface profile analysis reflectometer (SOFIA) at BL16 of Materials and Life Science Experimental Facility (MLF) in J-PARC (Proposal No.2015B0016). The NR spectrum was measured as a function of the momentum transfer, Qz = (4π/λ)sin θ, in the Qz range between 0.1 and about 0.45 nm-1. The obtained NR spectra were fitted with Motofit based on a Parratt formalism [2] [3]. Results and Discussion After the CV measurement, the morphology of the carbon surface was clearly changed as expected. Fig. 2 shows a color map of the reflectivity profiles in the Qz and time plane for the 1st and 2nd charge and discharge cycles in order to demonstrate the overall data for the present NR measurements. NR is found to drastically change at potentials between 1.5 and 0.05 V corresponding to the lithiation reaction, and between 0.05 and 2.5 V corresponding to the delithiation reaction. The change in NR along the Qz axis naturally reflects the formation and variation of SEI. Fig. 3 shows the Scattering length density (SLD) as a function of depth and time. The data were obtained by fitting the NR spectra with a four-layer model. The change in thickness of carbon electrode indicates the volumetric change induced by the lithiation and delithiation reactions into and from carbon. The decrease in SLD of carbon also supports the lithiation reaction into carbon, because Li exhibits a negative coherent scattering length. More correctly, as potential decreases from 1.5 to 0.05 V, the width of the carbon film increases from 67 to 83 nm. On the contrary, the boundary between electrode and electrolyte clearly changes with potential, indicating the formation of SEI. That is, as potential decreases from 1.0 V, SLD increases from 2.4 to 3.2 (x 10-4) nm-2, while the thickness increases from 18 to 36 nm at potential = 0.05 V during the initial lithiation reaction. This clearly demonstrates the growth of SEI during the lithiation reaction. Consequently, with NR measurements in the most intense neutron source, we have successfully observed the formation and growth of SEI at the boundary of the carbon electrode and liquid electrolyte during electrochemical charge and discharge reactions. Such measurements will provide an insight how to improve the performance of LIBs. References [1] H. Kawaura et al, ACS Appl. Mater. Interfaces, 8(2016) 9540. [2] L. G. Parratt, Phys. Rev., 95(1954) 359. [3] A. Nelson, J. Appl. Cryst., 39(2006) 273. Figure 1

In this paper, we report on the pore-expansion of organically functionalized monodispersed mesoporous silica spheres (MMSS) and their use as adsorbents for bulky dyes as well as proteins. Solvothermal treatment under a water/ethanol mixture led to pore-expansion of the organically functionalized MMSS while retaining their organic functionality and high monodispersity. Mesopores were expanded to 3.5 nm from 2.5 nm for amino-functionalized MMSS, and to 3.3 nm from 2.4 nm for carboxyl-functionalized MMSS. TEM observations revealed that the mesopores were aligned radially from the center towards the outside of the spheres, as observed in the previously reported MMSS without organic groups. It was confirmed that pore-expanded organically functionalized MMSS showed excellent adsorption properties for bulky dye molecules and proteins. In addition, trypsin-immobilized carboxyl-functionalized MMSS with large mesopores showed high catalytic activity. The turnover frequency in hydrolysis was enhanced by 1.5 times compared to the original particles.

In this paper, we report on the pore expansion of monodispersed mesoporous silica spheres (MMSS) by a swelling agent incorporation method, by which swelling agents such as various hydrocarbons were incorporated into mesopores. Mesopores were expanded to more than twice the size (5.5 nm) of the original one (2.5 nm). In this method, pore expansion of MMSS was achieved while radially ordered hexagonal mesopores with spherical morphology and high monodispersity were retained. In addition, we have successfully obtained highly monodispersed porous FePt—MMSS composites by incorporating FePt precursors into the pore-expanded MMSS. The composites had both ferromagnetic behavior with coercivity of 3.3 kOe at room temperature and mesoporosity with pore volume of 0.74 cm3g−1, which is enough to incorporate a variety of chemicals, nanoparticles, and proteins, such as drugs, quantum dots, enzymes, and DNA molecules. They have potential applications in drug delivery systems, gene delivery systems, magnetic hyperthermia...

A ceramic composite mimicking the pervasively cracked microstructure of flexible sandstone (itacolumite) was successfully synthesized by sintering two ceramic materials with different thermal expansion coefficients. A combination of granular KZr2(PO4)3 (high thermal expansion) and powdered KAlSi2O6 (low thermal expansion) resulted in a material with a jigsaw-like three-dimensional cracking microstructure similar to that of itacolumite. The synthesized composite was found to exhibit ductile deformation.

Tryglycine sulphate (TGS) and (phosphoric acid)-substituted tryglycine sulphate (TGSP) crystals were fabricated on a TGS seed crystal by dropping TGS or TGSP solution. The Curie temperatures of the resultant TGS and TGS0.5P0.5 crystals were 46 and 55 °C, respectively. A compositionally graded TGSP crystal was also fabricated by dropping the concentration-controlled TGS–TGSP solution, and the composition of the functionally graded material (FGM)–TGSP crystal was changed continuously from TGS to TGS0.5P0.5 with a composition ratio step of 0.05. The FGM–TGSP specimen showed a flat dielectric curve with a dielectric constant of 2450±7% in the range from 46 to 54 °C.

A formation mechanism for monodispersed mesoporous silica spheres was investigated from the viewpoint of both particle growth and the progress of the condensation of the silica precursor. The particle growth of monodispersed mesoporous silica spheres was studied by TEM observation. The development of the mesopores was examined by in situ X-ray diffraction measurements. The condensation reaction of the silica precursor was analyzed by silicic acid titration and pH-conductivity measurements during the synthesis. It was found that small particles emerged suddenly after the commencement of the synthesis, and then the residual silica precursors reacted preferentially with the surface silanols on these existing particles. This led to the formation of monodispersed mesoporous silica spheres. Conversely, new small particles emerge throughout the synthesis in the case of a heterogeneous system. To confirm the preferential reaction of the silica precursors with the surface silanols, expansion of the existing particles was carried out by adding more silica precursor after the completion of the synthesis. It was found that the sizes of the particles were enlarged by the successive addition of more of the silica precursor. Surprisingly, the radial alignment of the hexagonal mesopores was still retained in the expanded particles. In addition, by the addition of a different silica precursor to the initial one, highly monodispersed core/shell mesoporous silica spheres possessing a hydrophilic core and a hydrophobic shell were successfully obtained for the first time.

The inorganic and organic hybrid compound, [O=VPd(2-Pyd-)4]n (2-Pyd- = 2-pyridonate) (1), was synthesized by assembling its monomer units in the organic solution. X-ray absorption spectroscopic (XAFS) studies indicated that oxidation states of the vanadium and palladium ions in 1 were +IV and +II, and the distance between them was estimated to be 2.698-2.700 Å. Scanning electron microscope (SEM) observation revealed that the compound 1 shapes in long columnar crystals with micrometer-sized cross section. EXAFS and IR studies suggested that the O=V oxygen atom interacted to the central palladium ion in the neighboring monomer unit, forming the inorganic infinite chain structure, -(O=V-Pd)n-, in the columnar crystals of 1.

Porous titania, alumina and zirconia ceramic woods with wood-like microstructures, analogous to that of silicified wood, were prepared from natural woods as templates. The production of these ceramic woods was performed by the following process: (1) infiltration of metal alkoxide into wood specimens, (2) hydrolysis of the alkoxide in the cell structure to form titania, alumina or zirconia gels, (3) firing in air to form titania, alumina or zirconia ceramic woods. The resulting titania, alumina and zirconia ceramic woods were studied by means of an X-ray diffractometer, a mercury porosimeter and a scanning electron microscope. The microstructure of these ceramic woods retained the same structure as that of the raw wood: with the pore sizes corresponding to those of the original wood, and the major pores being unidirectionally connected.

Four tetrakis(1-methyluracilato)palladium complexes containing alkali metal ions, [Li 2 Pd(1-MeU − ) 4 ] ( 1 ), [Na 2 Pd(1-MeU − ) 4 ] ( 2 ), [K 2 Pd(1-MeU − ) 4 ] ( 3 ), and [Cs 2 Pd(1-MeU − ) 4 ] ( 4 ), have been prepared from M 2 PdCl 4 (M=Li + , Na + , K + , and Cs + ) and 4 equiv. of 1-methyluracil (1-MeUH). The X-ray crystal structure analyses of complexes 2 , 3 and 4 have revealed that each palladium atom is coordinated in a square-planar geometry with four 1-MeUH-derived N3-deprotonated imidato groups, upright-oriented with angles of 60–70° from the basal coordination plane. Interestingly, the carbonyl groups of the four imidato rings form two cavities above and below the Pd(II) atom, and two alkali metal ions are incorporated with PdM distances of 3.007(4) and 3.137(3) A for 2 , 3.432(3) and 3.594(3) A for 3 , and 3.746(1) and 3.999(1) A for 4 , respectively. The cavity sizes of the three complexes are tunable according to the ionic radii of the alkali metal ions. 1 H NMR spectra of complexes 1 – 4 indicate that all proton signals of the 1-MeU − moiety are shifted up-field relative to those of free 1-MeU − . The magnitude of the up-field shifts, 1 2 3 4 , corresponds well to the order of the ionic potentials of alkali metal ions. These up-field shifts are reduced by coordination of 5-fluoro-1-methyluracil in place of 1-MeUH, indicating that the electron-donating character of 1-MeU − to Pd(II) is decreased by substitution with an electron-withdrawing fluoro group. These observations suggest that the up-field shifts may be rationalized in terms of π-back donation from Pd(II) dπ-orbital to imidato π*-orbital and the ionic potentials of alkali metals, which have also been investigated on the basis of the DFT calculation. On the basis of these characteristic features, the [M 2 Pd(1-MeU) 4 ] complexes may be classified as a new type of metallo-podand that captures alkali metal ions.

Functionally graded PMN-PT ceramics, which had a continuously varying graded composition from one surface toward the other of the specimen, were examined with respect to their dielectric property. Specimens were prepared by sintering superposed layers of green compacts of (1-x)PMN-xPT solid solutions with different values of x. The electric permittivity (e) of single-phase (1-x)PMN-xPT ceramics showed a peak at the Curie temperature, which shifted towards higher temperatures with increasing x. On the other hand, the profile of e vs temperature (T) for the graded PMN-PT ceramics experienced a linear characteristic. Furthermore, a flat profile was obtained by varying the volume of layers. The relative permittivity was 10000 ± 200 in the temperature range from room temperature to 120°C. In addition, the temperature coefficient of permittivity could be arbitrary adjusted by cutting the specimen diagonally.

本研究の目的は, 地震に伴う災害リスク評価に基づく斜面補強を戦略的に立案する方法を提案するものである. 具体的な事例としては, 全国主要都市での高速道路に近接する斜面を対象とし, 各地域での地震動特性および, 各高速道路の利用状況に応じた被害推定に基づき, コスト次元でのリスク評価を実施した. そして, その算定されたリスクに基づく費用便益解析により, 同じ形状の斜面であっても, その補強対策は地震動の地域性および各道路での損害の大きさの相違によって異なることが定量的に表現可能となることを示した. これらの結果より, 本研究で提案する手法は, 合理的に斜面の補強策を立案する上で極めて有効であることを示した.

The existence of a CH-π interaction has clearly been demonstrated by use of the ternary metal (Cu(II), Pd(II)) complexes involving o-/m-/p-methyl substituted L-phenylalanine (L-o-mPhe, L-m-mPhe, L-p-mPhe) and 1,10-phenanthroline (phen) on the basis of 1H NMR, electronic absorption, and CD spectroscopies, and X-ray diffraction method. The crystal structure of [{Cu(p-mPhe)(phen)}2{Cu(phen)2}(μ3-CO3)](ClO4)2 has revealed a marked structural feature suggesting CH-π and/or π–π interactions, although [Cu(L-o-mPhe)(phen)(H2O)]ClO4 does not show any interaction. CD spectra in the d–d region for [Cu(L-o-mPhe)(phen)]ClO4, [Cu(L-m-mPhe)(phen)]ClO4, and [Cu(L-p-mPhe)(phen)]ClO4 in aqueous solution have exhibited an obvious negative Cotton effect, and the magnitudes have significantly been reduced in dioxane/water in the order: [Cu(L-p-mPhe)(phen)]ClO4 ≤ [Cu(L-m-mPhe)(phen)]ClO4 < [Cu(L-o-mPhe)(phen)]ClO4. 1H NMR spectra of [Pd(L-o-mPhe)(phen)]ClO4, [Pd(L-m-mPhe)(phen)]ClO4, and [Pd(L-p-mPhe)(phen)]ClO4 have exhibited...

By adapting a novel surfactant exchange method, in which surfactants inside mesopores are completely exchanged by surfactants with longer alkyl chain lengths, pore-expansion of monodisperse mesoporous silica spheres (MMSS) with radially ordered hexagonal regularity was attained while retaining spherical morphology and high monodispersity.

Reaction of Cu(ClO4)2·6H2O with l -glutamic acid ( l -glu) in 1:1 or 1:2 molar ratio at pH 5 gave only the complex [Cu( l -glu)-(H2O)]·H2O, whose crystal structure revealed that the copper atom was coordinated in square-planar geometry, with the amino nitrogen and the carboxylate oxygen of l -glu, the side-chain carboxylate oxygen of a neighboring l -glu, and the oxygen of a water molecule in the equatorial positions. Weak coordination of two additional glutamate oxygens to both axial positions complete a distorted octahedron. The [Cu( l -glu)(H2O)] units linked by coordination of the side-chain carboxylate group form an infinite left-handed single helix; the use of d -glu in place of l -glu gives a right-handed helix, indicating that the glu enantiomerism determines the helicity. Thermogravimetric and differential thermal analyses of the complex showed reversible desorption of just two water molecules at 95–130°C, whose behavior was examined by ESR and circular dichroism spectral and powder X-ray diffraction methods in solid state. The crystals obtained from the reaction of Cu(II) ion with dl -glu showed spontaneous resolution.

This paper describes fragility evaluation results estimated by a seismic PRA procedure on the structural and functional failure of a building and equipment. The applicability of the response estimation method of the seismic PRA procedure is also discussed. The probability of failure is evaluated by a previously established PRA procedure and by Monte Carlo simulation. The response is calculated by five different methods in order to study the characteristics of simplified factors of the PRA procedure. According to the results, it is concluded that the proposed seismic PRA procedure gives adequate results when compared with the Monte Carlo simulation method. The PRA procedure can be used for a simplified evaluation method.

Negative thermal expansion material ZrW 2 O 8 /Zr 2 WP 2 O 12 composite was prepared by liquid phase sintering. The apparent density of ZrW 2 O 8 without any sintering additive was about 3.7 g/cm 3 , corresponding to about 73% of its theoretical density. However, the relative density of the samples, sintered with more than 5 mol% P 2 O 5 was about 90%. The identified phases were mainly ZrW 2 O 8 with small amounts of WO 3 , ZrO 2 and Zr 2 WP 2 O 12 by XRD. The intensity of Zr 2 WP 2 O 12 peaks increased with increasing P 2 O 5 content. It was surmised that the melting of ZrO 2 –P 2 O 5 resulted in liquid phase formation, which is then converted to Zr 2 WP 2 O 12 on the final stage of sintering. Therefore, Zr 2 WP 2 O 12 phase was observed at the gap between the ZrW 2 O 8 grains and at the triple junctions. The ceramics sintered with 20 mol% P 2 O 5 showed a negative thermal expansion coefficient of − 4.0 × 10 − 6 °C − 1 .

Characteristics of pyrimidine bases are demonstrated on the crystals of the ternary copper(II) complexes consisting of bpy and pyrimidine-amino acid. Hemiprotonated CH + :C pair is important for the formation of intermolecular triple hydrogen bonding interaction, mimicking i-motif of DNA. The electron-donating effect in thymine ring among pyrimidine bases also promotes intermolecular π-π stacking interaction.

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A novel [Na2Pd(1-MeU−)4(H2O)2]n (1) columnar complex is prepared from the reaction of an aqueous solution containing Na2PdCl4 with four equivalent amount of 1-methyluracil (1-MeUH) in the presence of Na2CO3. X-ray structure of 1 reveals that the complex forms an infinite supramolecular channel structure in the crystal.

The X-ray crystal structure of a unique multinuclear complex, [Na2Cu2Pd(wil)4(H2O)4], prepared from Na2PdCl4, Cu(ClO4)2·6H2O and DL-willardiine (wil) is determined, which reveals that the palladium atom is coordinated by the imide nitrogens of four wil ligands; two sodium ions are retained in the cavities fromed by the coordinated wil molecules.