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In all-solid-state batteries (ASSB), increasing the thickness of electrodes is essential for increasing the energy density. However, this limits the C-rate performance, particularly for electrodes with a large volume fraction of active materials (AMs), transport of ions in the electrode is hindered, leading to poor utilization of AMs in ASSBs. To accelerate the development of ASSBs, it is highly desirable to develop analytical methods for understanding the utilization of AMs in thick electrodes. In this paper, we propose a novel impedance analysis method using the transmission line model (TLM) for estimating the utilization of AMs in an electrode in terms of effective electrode thickness. In the TLM model, electrode thickness is treated as a variable instead of a fixed parameter in the conventional sequence. Hence, the modified C-rate performance considering the TLM-calculated thickness exhibits an identical trend regardless of the actual electrode thickness, suggesting the calculated electrode thickness reflects the effective electrode thickness. This indicates effective utilization of AMs for electrochemical reactions. We also demonstrate the versatility of this method by using different electrode specifications.

A binary system of Li2TiO3–LiMnO2 is systematically examined by joint experimental and theoretical studies as electrode materials for Li storage applications. Increase in a fraction of Li2TiO3 effectively activates anionic redox, and thus holes are reversibly formed on oxygen by electrochemical oxidation. Such holes are energetically stabilized through π-type interaction with Mn t2g orbital as suggested by theoretical calculation. However, excess enrichment of Li2TiO3 fractions in this binary system results in the oxygen loss as an irreversible process on delithiation because of a non-bonding character for Ti–O bonds coupled with the formation of O–O dimers, which are chemically and electrochemically unstable species. Additionally, detailed electrochemical study clearly shows that Li migration kinetics is relatively slow, presumably coupled with low electronic conductivity. Nevertheless, nanosizing of primary particles is an effective strategy to overcome this limitation. The nanosized sample prepared by mechanical milling delivers a large reversible capacity, ∼300 mA h g−1, even at room temperature and shows much improved capacity retention. Formation and stabilization of holes for the nanosized sample are also directly evidenced by soft X-ray absorption spectroscopy. From these results, factors affecting the reversibility of anionic redox as emerging new chemistry and its possibility for energy storage applications are discussed in more details.

Heterogeneous catalysis of alkenes to alkanes is of great importance in chemical industry, but more efficient and reusable heterogeneous catalysts are still demanded. Here, we report a metallically gradated composite of a silicon nanowire array and palladium nanoparticles which are reused for the hydrogenation of an alkene. The catalyst promotes the hydrogenation of stilbene with atmospheric hydrogen (0.1 MPa) to give diphenylethane quantitatively. The recovered catalyst can be reused, and mediates the reaction without loss of yield more than one hundred times, whereas the stability of Pd/C degrades rapidly over 10 cycles of reuse. The catalyst allows the hydrogenation of a variety of alkenes, including tetra-substituted olefins. Structural investigation reveals that palladium nanoparticles are metallically gradated onto the silicon nanowire array under mild conditions by agglomeration of palladium silicide, as confirmed by XAFS and XPS together with argon-ion sputtering. This means of metal agglomeration immobilization may be applicable to the preparation of a variety of metal nanoparticle catalysts. Degradation of heterogeneous catalysts limits their cost efficiency and sustainability. Here a hydrogenation catalyst that is stable over a hundred cycles of reuse is reported, with stability attributed to the formation of an agglomeration at the palladium/silicon interface.

Novel hydrogen-selective amorphous silica membranes were developed by chemical vapor deposition (CVD) method using dimethoxydimethylsilane (DMDMS) as the silica precursor. The preparation conditions were optimized by varying the DMDMS saturated vapor concentration in the CVD reactor and the CVD time. The membrane prepared under optimized conditions demonstrated excellent hydrogen-selective performance, exhibiting a hydrogen permeance of 2.8 × 10−7 mol m−2 s−1 Pa−1 at 773 K, which is approximately three times larger when compared with silica membranes prepared with tetramethoxysilane (TMOS). And the ideal selectivity of hydrogen to nitrogen at the same temperature was 2.3 × 103. The estimation of pore size by the normalized Knudsen-based permeance (NKP) method and the structural analysis by XPS indicated that the DMDMS-derived membrane possessed a thinner active separation layer compared with the TMOS-derived membrane, while the pore size was comparable. Thus, membrane thickness was influenced by the slight difference in the chemical structures of the silica precursors, resulting in a higher hydrogen permeance. Finally, excellent hydrothermal stability of the DMDMS-derived membrane was demonstrated.

We investigated the magnetization reversal process of Ni wires fabricated on a single-crystal Y-cut 128° LiNbO 3 substrate using magnetoresistance measurement, Kerr microscopy, and micromagnetic simulation. Our study reveals the stripe-domain structure, which is originated by the competition between the shape magnetic anisotropy and additional magnetic anisotropy induced by the heterojunction, allows us to provide a pinning necessary to control the domain-wall displacement.

One of the key challenges when developing magnesium rechargeable batteries (MRB) is to develop Mg-intercalation cathodes exhibiting higher redox potentials with larger specific capacities. Although Mg-transition-metal spinel oxides have been shown to be excellent candidates as MRB cathode materials by utilizing the valence change from trivalent to divalent of transition metals starting from Mg insertion, there is no clear evidence to date that Mg can be indeed extracted from the initial spinel hosts by utilizing the change from trivalent to quadrivalent. In this work, we clearly present various experimental evidences of the electrochemical extraction of Mg from spinel MgMn2O4. The present electrochemical charge, i.e., extraction treatment of Mg, was performed in an ionic liquid at 150 °C to ensure Mg hopping in the spinel host. Our analyses show that Mg can be extracted from Mg1−xMn2O4 up to x = 0.4 and, afterwards, successively be inserted into the Mg-extracted (demagnesiated) host via a two-phase reaction between tetragonal and cubic spinels. Finally, we also discuss the difference in electrochemical features between LiMn2O4 and MgMn2O4.

The competition between magnetic shape anisotropy and the induced uniaxial magnetic anisotropy in the heterojunction between a ferromagnetic layer and a ferroelectric substrate serves to control magnetic domain structures as well as magnetization reversal characteristics. The uniaxial magnetic anisotropy, originating from the symmetry breaking effect in the heterojunction, plays a significant role in modifying the characteristics of magnetization dynamics. Magnetoelastic phenomena are known to generate uniaxial magnetic anisotropy, however, the interfacial electronic states that may contribute to the uniaxial magnetic anisotropy have not yet been adequately investigated. Here, we report experimental evidence concerning the binding energy change in the ferromagnetic layer/ferroelectric substrate heterojunction using X-ray photoemission spectroscopy. The binding energy shifts, corresponding to the chemical shifts, reveal the binding states near the interface. Our results shed light on the origin of the uniaxial magnetic anisotropy induced from the heterojunction. This knowledge can provide a means for the simultaneous control of magnetism, mechanics, and electronics in a nano/microsystem consisting of ferromagnetic/ferroelectric materials.

To clarify the origin of the polarization of magnesium deposition/dissolution reactions, we combined electrochemical measurement, operando soft X-ray absorption spectroscopy (operando SXAS), Raman, and density functional theory (DFT) techniques to three different electrolytes: magnesium bis(trifluoromethanesulfonyl)amide (Mg(TFSA)2)/triglyme, magnesium borohydride (Mg(BH4)2)/tetrahydrofuran (THF), and Mg(TFSA)2/2-methyltetrahydrofuran (2-MeTHF). Cyclic voltammetry revealed that magnesium deposition/dissolution reactions occur in Mg(TFSA)2/triglyme and Mg(BH4)2/THF, while the reactions do not occur in Mg(TFSA)2/2-MeTHF. Raman spectroscopy shows that the [TFSA]- in the Mg(TFSA)2/triglyme electrolyte largely does not coordinate to the magnesium ions, while all of the [TFSA]- in Mg(TFSA)2/2-MeTHF and [BH4]- in Mg(BH4)2/THF coordinate to the magnesium ions. In operando SXAS measurements, the intermediate, such as the Mg+ ion, was not observed at potentials above the magnesium deposition potential, and the local structure distortion around the magnesium ions increases in all of the electrolytes at the magnesium electrode|electrolyte interface during the cathodic polarization. Our DFT calculation and X-ray photoelectron spectroscopy results indicate that the [TFSA]-, strongly bound to the magnesium ion in the Mg(TFSA)2/2-MeTHF electrolyte, undergoes reduction decomposition easily, instead of deposition of magnesium metal, which makes the electrolyte inactive electrochemically. In the Mg(BH4)2/THF electrolyte, because the [BH4]- coordinated to the magnesium ions is stable even under the potential of the magnesium deposition, the magnesium deposition is not inhibited by the decomposition of [BH4]-. Conversely, because [TFSA]- is weakly bound to the magnesium ion in Mg(TFSA)2/triglyme, the reduction decomposition occurs relatively slowly, which allows the magnesium deposition in the electrolyte.

An ongoing challenge with lithium–oxygen (Li–O2) batteries is in deciphering the oxygen evolution reaction (OER) process related to the slow decomposition of the insulating lithium peroxide (Li2O2). Herein, we shed light on the behavior of Li2O2 oxidation by exploiting various in situ imaging, gas analysis, and electrochemical methods. At the low potentials 3.2–3.7 V (vs Li/Li+), OER is exclusive to the thinner parts of the Li2O2 deposits, which leads to O2 gas evolution, followed by the concomitant release of superoxide species. At higher potentials, OER initiates at the sidewalls of the thicker Li2O2. The succeeding lateral decomposition of Li2O2 indicates the preferential Li+ and charge transport occurring at the sidewalls of Li2O2. To ameliorate the OER rate, we also investigate an alternative approach of rerouting charge carriers by using soluble redox mediators. Our in situ probes provide insights into the favorable charge-transport routes that can aid in promoting Li2O2 decomposition.

Random copolymers (P(M100-m/T m )) composed of 2-methacryloyloxyethyl phosphorylcholine (MPC), which suppresses protein adsorption, and 3-(triethoxysilyl)propyl methacrylate (MTEOS), which can be covalently fixed on a glass surface, were prepared via photoinitiated radical polymerization. When P(M100-m/T m ) was coated on a glass surface, a protein antifouling effect could be observed because of the presence of MPC units on the glass surface. To confirm the coating of the glass surface with P(M100-m/T m ) by fluorescence microscopy, pyrene-labeled P(M100-m/T m ) was also prepared. An ethanol solution of P(M100-m/T m ) was spin-coated on the glass, which was exposed to NH3 vapor to promote the reaction of the pendant triethoxysilyl groups in P(M100-m/T m ) with silanol groups on the glass. The coating of the glass with MPC was confirmed by fluorescence microscopy. The protein antifouling effects of the P(M100-m/T m )-coated glass were confirmed using fluorescence-labeled proteins. It is expected that P(M100-m/T m ) can be applied as a surface-coating agent on glass containers for protein formulations. Random copolymers (P(M100-m/T m )) composed of 2-methacryloyloxyethyl phosphorylcholine, which suppresses protein fouling, and 3-(triethoxysilyl)propyl methacrylate, which can react covalently to the glass surface, were prepared via photoinitiated radical polymerization. Coating of the glass with P(M100-m/T m ) was confirmed by red fluorescence from Rhodamine 6G. The protein antifouling properties of the P(M100-m/T m ) coating on glass were confirmed using fluorescence-labeled proteins.

The oxygen storage capability and related defect structure of tetrahedral orthochromite(V) compound YCr1–xPxO4 (x = 0, 0.3, 0.5, and 0.7) were investigated by employing thermal gravimetry and in situ X-ray spectroscopy for reversible oxygen store/release driven by heating–cooling cycles in the temperature range from 50 to 600 °C. YCr1–xPxO4 started releasing oxygen as heated from 50 °C under ambient atmosphere, with reduction of CrV to CrIV, while the reduced YCr1–xPxO4−δ phase was significantly reoxidized via absorbing oxygen by cooling to 50 °C under ambient atmosphere, recovering the original stoichiometric phase. Operando X-ray adsorption spectroscopy and first-principles calculations demonstrate that nonstoichiometric YCr1–xPxO4−δ phases were stabilized by forming linking polyhedral CrIV2O76– via corner sharing between oxygen-deficient CrIVO32– and adjacent CrIVO44–. YCr1–xPxO4 was found to have an extremely low reduction enthalpy of about 20 kJ mol–1 probably due to the relatively high reduction pot...

One of the key challenges when developing magnesium rechargeable batteries (MRB) is to develop Mg-intercalation cathodes exhibiting higher redox potentials with larger specific capacities. Although Mg-transition-metal spinel oxides have been shown to be excellent candidates as MRB cathode materials by utilizing the valence change from trivalent to divalent of transition metals starting from Mg insertion, there is no clear evidence to date that Mg can be indeed extracted from the initial spinel hosts by utilizing the change from trivalent to quadrivalent. In this work, we clearly present various experimental evidences of the electrochemical extraction of Mg from spinel MgMn

Rapid progress of quantum transport study in topological Dirac semimetal, including observations of quantum Hall effect in two-dimensional (2D) Cd$_{\mathrm{3}}$As$_{\mathrm{2}}$ samples, has uncovered even more interesting quantum transport properties in high-quality and three-dimensional (3D) samples. However, such 3D Cd$_{\mathrm{3}}$As$_{\mathrm{2}}$ films with low carrier density and high electron mobility have been hardly obtained. Here we report the growth and characterization of 3D thick Cd$_{\mathrm{3}}$As$_{\mathrm{2}}$ films adopting molecular beam epitaxy. The highest electron mobility ($\mu$ = 3 $\times$ 10$^{4}$ cm$^{2}$/Vs) among the reported film samples has been achieved at a low carrier density ($\textit{n} = 5$ $\times$ 10$^{16}$ cm$^{-3}$). In the magnetotransport measurement, Hall plateau-like structures are commonly observed in spite of the 3D thick films ($\textit{t} = 120$ nm). On the other hand, field angle dependence of the plateau-like structures and corresponding Shubunikov-de Haas oscillations rather shows a 3D feature, suggesting the appearance of unconventional magnetic orbit, also distinct from the one described by the semiclassical Weyl-orbit equation., Comment: 11 pages, 3 figures + supplementary 6 pages, 3 figures

In lithium oxygen (Li–O2) batteries, controlling the structure of lithium peroxide (Li2O2) can reduce the large overpotential of the charge process as this affects the ionic and electronic conductivities of Li2O2. We demonstrate, for the first time, the in situ structural tuning of Li2O2 during the discharge process by virtue of the surface properties of carbon nanotube electrodes. We tailored carbon nanotube surfaces to decouple oxygen functional groups, defective edges, and graphitization, which directly influence the surface-binding affinity of O2 and LiO2. Consequently, conformal and completely amorphous Li2O2 films form in the presence of oxygen functional groups, which can facilely decompose in the subsequent charge. In contrast, crystalline Li2O2 particles grow in more ordered carbon electrodes and consequently require higher overpotential for decomposition. Our comprehensive study reveals the possibility of facile decomposition of Li2O2 by the surface engineering of carbon electrode and gives insi...

We synthesized 4-azidophenylcarbonyloxyethyl-2-bromoisobutyrate (AzEBI) for construction of a polymer brush layer on a desired area on various polymeric substrates. After 3.0 min of exposure to UV irradiation, the phenylazide groups of AzEBI decomposed and formed covalent bonds with the polymeric substrate surfaces to introduce an initiator of atom transfer radical polymerization (ATRP). The reaction area of AzEBI was regulated using a photomask during photoreaction and surface initiated ATRP of 2-methacryloyloxyethyl phosphorylcholine (MPC) occurred on the desired part of the surface. In the area with poly(MPC), the surface was superhydrophilic and the adhesion of HeLa cell was effectively suppressed. The AzEBI allows the construction of polymer brush layer in anywhere and would expand the potential application of ATRP to prepare polymer brush layer on polymeric substrates.

Lithium-sulfur (Li-S) battery has higher theoretical specific capacity than commercial lithium-ion batteries. However, one of serious problems in sulfur cathode to be solved to realize a commercial Li-S battery is polysulfide dissolution, causing lowering charge-discharge capacity and round-trip efficiency. In previous studies, glyme-Li+ solvent ionic liquid (SIL)1) and polypyrrole film containing ionic liquid2) were proposed to mitigate dissolution of polysulfide. Meanwhile, dependence of sulfur cathode’s reaction mechanism on polysulfide solubility of electrolyte is still unclear. In this study, electrochemical impedance spectroscopy (EIS) at various depth of discharge was performed in two types of lithium-sulfur batteries using electrolytes with different polysulfide solubility. This paper describes that polysulfide solubility in electrolyte largely influences the impedance response at initial stage of discharge in Li-S batteries. For cathode and electrolyte, X-ray absorption near edge structure (XANES) was also performed in order to analyze the valence of sulfur species at various depth of discharge. Figure 1 shows discharge curves of Li-S cells with polysulfide soluble electrolyte (1M LiTFSI in 1,3-dioxolane (DOL)/1,2-dimethoxyethane (DME) 1:1 (v/v)) and with polysulfide insoluble SIL electrolyte (Li(G3)TFSI/hydrofluoroether (HFE) 1:4 (v/v)). Figure 2 (a) and (b) show Nyquist plots obtained by the cells using DOL/DME and SIL, respectively. A remarkable difference was observed in the diameter of semicircles in a frequency range of 1 kHz – 10 Hz; in both cases, semicircle decrease as discharge progression in the same manner, while decrease of the semicircles with DOL/DME was more notable. In addition, another semicircle in a frequency range of 10 Hz - 1 Hz was observed only in the Nyquist plots with SIL electrolyte. These results indicate that the semicircles in higher frequency region (1 kHz – 10 Hz) are attributed to dissolved polysulfide and the semicircle in lower frequency region (10 Hz – 1 Hz) is attributed to undissolved polysulfide. XANES measurement confirms that signal by sulfur (2472 eV) decreased until potential reached 2.1 V with DOL/DME and until 1.5 V with SIL. These results indicate that reduction of sulfur proceeds until 2.1 V with DOL/DME and until 1.5 V with SIL which is in good agreement with the result from impedance response by EIS. Acknowledgement This work was partly supported by Advanced Low Carbon Technology Research, Development Program Special Priority Research Area “Next-Generation Rechargeable Battery” (ALCA-Spring) from the Japan Science and Technology Agency (JST) (Grant Number JPMJAL1301). Reference (1) Kaoru Dokko et al., Journal of the Electrochemical Society, Volume 160, Issue 8, A1304-A1310 (2013). (2) Natsuki Nakamura et al., J Power Sources, 274, 1263-1266 (2015). Figure 1

Sulfur is a promising cathode material for the lithium based battery because of its advantages such as eco-friendness, abundance in nature, and high theoretical capacity of 1675 mAh g-1. However, sulfur cathodes are not without their own intrinsic problems such as low ionic and electronic conductivity, large volumetric expansion upon lithiation from S8 to Li2S, and the dissolution of so-called polysulfide intermediates (Li2Sx where x represents a value between 4 and 8). In previous studies, glyme-Li+ solvent ionic liquid (SIL)1) and polypyrrole film containing ionic liquid2) were proposed to mitigate dissolution of polysulfide. Meanwhile, dependence of sulfur cathode’s reaction mechanism on polysulfide solubility of electrolyte is still unclear. In this study, electrochemical impedance spectroscopy (EIS) at various depth of discharge was performed in two types of lithium-sulfur batteries using electrolytes with different polysulfide solubility. This paper describes that polysulfide solubility in electrolyte largely influences the impedance response at mid - end stage of discharge in Li-S batteries. Figure 1 shows discharge curves of Li-S cells with polysulfide soluble electrolyte (1M LiTFSI in 1,3-dioxolane (DOL)/1,2-dimethoxyethane (DME) 1:1 (v/v)) and with polysulfide insoluble SIL electrolyte (Li(G3)TFSI/hydrofluoroether (HFE) 1:4 (v/v)). Figure 2 (a) and (b) show Nyquist plots obtained by the cells using DOL/DME and SIL, respectively. A remarkable difference was observed in the diameter of semicircles in lower frequency range of 10Hz – 0.1 Hz at potential of 2.1 - 1.5 V. The semicircle was observed with SIL at 2.1 V, and the diameter of the semicircle increased with discharge progression. No semicircle was observed at 1.9-1.5V. On the other hand, no semicircle with DOL/DME was observed at 2.1 - 1.5 V. However, impedance response at 2.1 V changed to that at 1.9 - 1.5V. The difference at 2.1V was attributed to DOD and/or state of polysulfide in electrolyte. There was no large difference of impedance response with these electrolytes at 1.9 V -1.5 V. It is thought that similar (semi-) solid-state reactions without electrolyte was occurred, because of no effect of solving polysulfide of Li2S2 and Li2S in both electrolytes. Acknowledgement This work was partly supported by Advanced Low Carbon Technology Research, Development Program Special Priority Research Area “Next-Generation Rechargeable Battery” (ALCA-Spring) from the Japan Science and Technology Agency (JST) (Grant Number JPMJAL1301). Reference (1) K. Dokko et al., J. Electrochem. Soc., 160, A1304-A1310 (2013). (2) N. Nakamura et al., J Power Sources, 274, 1263-1266 (2015). Figure 1

An ongoing challenge with lithium-oxygen (Li-O

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is widely used to build optoelectronic devices. However, as a hygroscopic water-based acidic material, it brings major concerns for stability and degradation, resulting in an intense effort to replace it in organic photovoltaic (OPV) devices. In this work, we focus on the perfluorinated ionomer (PFI) polymeric additive to PEDOT:PSS. We demonstrate that it can reduce the relative amplitude of OPV device burn-in, and find two distinct regimes of influence. At low concentrations there is a subtle effect on wetting and work function, for instance, with a detrimental impact on the device characteristics, and above a threshold it changes the electronic and device properties. The abrupt threshold in the conducting polymer occurs for PFI concentrations greater than or equal to the PSS concentration and was revealed by monitoring variations in transmission, topography, work-function, wettability and OPV device characteristics. Below this PFI concentration threshold, the power conversion efficiency (PCE) of OPVs based on poly(3-hexylthiophene-2,5-diyl):[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) are impaired largely by low fill-factors due to poor charge extraction. Above the PFI concentration threshold, we recover the PCE before it is improved beyond the pristine PEDOT:PSS layer based OPV devices. Supplementary to the performance enhancement, PFI improves OPV device stability and lifetime. Our degradation study leads to the conclusion that PFI prevents water from diffusing to and from the hygrosopic PEDOT:PSS layer, which slows down the deterioration of the PEDOT:PSS layer and the aluminum electrode. These findings reveal mechanisms and opportunities that should be taken into consideration when developing components to inhibit OPV degradation., Comment: 14 pages, 9 figures, 1 table, Journal of Materials Chemistry A 2018

We developed an in situ radiotracer method for diffusion studies in solids using short-lived α-emitting 8Li tracer. In the method, while implanting a pulsed 8Li beam into a solid material of interest, the α particles emitted into the implantation side of the sample surface were detected as a function of time. By changing the implantation depth and the detection angle against the sample surface according to lithium diffusivity (deep implantation and large angle with a large solid angle, or shallow implantation and small angle with a narrow solid angle), the method can be sensitive to a wide range of diffusion length ranging from micrometer scale to nanometer scale per second. The feasibility of the method was demonstrated by measuring the lithium diffusion coefficients to the order of 10−12 cm2/s in lithium ionic conductors.

Poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) possesses protein antifouling properties. Diblock copolymers (PMPC120-b-P(TSM/CEAx)y) composed of a PMPC block and random copolymer block with 3-(tris(trimethylsiloxy)silyl)propyl methacrylate (TSM) and 2-cinnamoylethyl acrylate (CEA) were prepared via reversible addition–fragmentation chain transfer (RAFT) radical polymerization. A thin film of PMPC120-P(TSM/CEAx)y formed on the surface of the poly(dimethylsiloxane) (PDMS) substrate due to physical adsorption of the TSM units to poly(dimethylsiloxane) (PDMS) and photo-crosslinking of the CEA units. A lattice pattern of PMPC120-P(TSM/CEAx)y on the PDMS surface was prepared using UV irradiation through a photomask. PMPC120-P(TSM/CEAx)y-coated PDMS demonstrated protein antifouling activity. Cell patterning could be achieved by culturing on the PMPC-patterned PDMS substrate.

Further increase in energy density of lithium batteries is needed for zero emission vehicles. However, energy density is restricted by unavoidable theoretical limits for positive electrodes used in commercial applications. One possibility towards energy densities exceeding these limits is to utilize anion (oxide ion) redox, instead of classical transition metal redox. Nevertheless, origin of activation of the oxide ion and its stabilization mechanism are not fully understood. Here we demonstrate that the suppression of formation of superoxide-like species on lithium extraction results in reversible redox for oxide ions, which is stabilized by the presence of relatively less covalent character of Mn4+ with oxide ions without the sacrifice of electronic conductivity. On the basis of these findings, we report an electrode material, whose metallic constituents consist only of 3d transition metal elements. The material delivers a reversible capacity of 300 mAh g−1 based on solid-state redox reaction of oxide ions., Energy storage by metal redox reactions sets strict limits on capacity in metal oxide cathode materials used in lithium-ion batteries. Here authors study stabilization of redox reactions at oxygen sites and demonstrate a cathode with a high reversible capacity enabled by the process.

As a possible example of radioactive ion (RI) beams for industrial application, intense beams of 7Be and 22Na used for wear diagnostics of mechanical parts is considered. For wear diagnostics, radioactive nuclei which have appropriate long life-time such as from several weeks to a few years are applicable. As those nuclei are located near the stable line, an in-flight RI beam separator can provide intense RI beams with enough high energy for implantation in atmosphere. Beam studies were performed to evaluate the intensity, uniformity, and depth profile of the implanted RI. We could achieve peak activity of 1.3 and 0.08 (kBq/μm)/(1 pμA × 1 h irradiation) at 13 and 50 μm peak depth with 20 and 150 μm maximum depth from the surface of an aluminum sample for 7Be and 22Na, respectively.

We are developing in situ diffusion measurements in solids using short-lived radioactive ion beams provided from an isotope separator on-line (ISOL). We examined the feasibility of a new in situ nanoscale diffusion measurement method using a radioactive 8 Li tracer by computer simulations. Under moderate experimental conditions, we have found that the detection limit of lithium diffusion coefficient can be improved to a low value of 1 × 10 - 12 cm 2 / s . Also, in situ sodium diffusion measurement in Na battery materials can be applicable using a radioactive 20 Na tracer. We found Na diffusion coefficients can be measured, ranging from 10 - 6 to 10 - 10 cm 2 / s by computer simulations.

The effect of the composition of the copolymer of 1-carboxy-N,N-dimethyl-N-(2-methacryloyloxyethyl) methanaminium inner salt (CMB) and n-butylmethacrylate (BMA) (poly(CMB-co-BMA)) as a surface modification polymer on the low-fouling properties of dynamically formed membranes was systematically investigated, and the optimum composition for this method was found to be 35:65 [mol:mol], which was prepared from the monomer solution containing 50:50 [mol:mol] of CMB:BMA in the feed (CMB50). This optimized dynamically formed membrane exhibited excellent low-fouling property against both hydrophilic protein and hydrophobic protein. To discuss the reason for this low-fouling property, the hydration states of the polyCMB–water and CMB50–water systems were measured using DSC. The results showed that the water structure in the polyCMB–water system is very similar to that in the poly(2-methacryloyloxyethyl phosphorylcholine) (polyMPC)–water system, which is one of the best-known zwitterionic polymers used for biomaterials, and that the water structure in the CMB50–water system has much in common with that in the polyCMB–water system. These water structures are one of the reasons for this system’s low-fouling properties.

We demonstrate that blending fluorinated molecules in PEDOT:PSS hole transport layers (HTL) induces charge transfers which impact on both charge extraction and photogeneration within organic photovoltaic (OPV) devices. OPVs fabricated with modified HTL and two photoactive polymer blends led systematically to power conversion efficiencies (PCE) increases, with PTB7:PC70BM blend exhibiting PCE of ~ 8.3 %, i.e. ~ 15 % increase compared to pristine HTL devices. A reduced device-to-device characteristics variations was also noticed when fluorinated additives were used to modify the PEDOT:PSS. Shading lights onto the effect of HTL fluorination, we show that the morphology of the polymer:PCBM blends remains surprisingly unaffected by the fluorinated HTL surface energy but that, instead, the OPVs are impacted not only by the HTL electronic properties (work function, dipole layer, open circuit voltage, charge transfer dynamic) but also by alteration of the complex refractive indices (photogeneration, short circuit current density, external quantum efficiencies, electro-optic modelling). Both mechanisms find their origin in fluorination induced charge transfers. This work points towards fluorination as a promising strategy toward combining both external quantum efficiency modulation and power conversion efficiency enhancement in OPVs. Charge transfers could also be used more broadly to tune the optical constants and electric field distribution, as well as to reduce interfacial charge recombinations within OPVs.

Gold was vacuum deposited on one side of 6-μm-diameter silica-gel particles to prepare Janus particles (JPs). Thiol-terminated pH-responsive poly(sodium 6-acrylamidohexanoate) (pAaH-SH) was immobilized onto the gold surface of JPs. pH-responsive flocculation and dispersion behavior of pAaH-grafted JPs can be observed with optical and fluorescence microscopy measurements.

In this work we present a general approach for bulk synthesis of various functionalized conducting polymer nano-networks. 3,4-ethylenedioxythiophene (EDOT) dimers are used to initiate the chemical polymerization of functionalized EDOT in the solvent system with high polarity, which leads to better control of the oxidation polymerization. Under these reaction conditions, various functionalized EDOT monomers form polymeric nano-network structures. We also evaluate the cell growth and cell viability on these conducting polymer nano-networks. The nano-networks provide highly biocompatible materials for PC12 cells and they show nice attachment on the surface. These properties of functionalized conducting polymer nano-networks indicate a promising platform for cell engineering.

Photovoltaic properties of bisazomethine dye (DE2) in vacuum-deposited thin films were examined for use in Schottky-type photovoltaic cells (ITO/DE2/Al). We measured dark and photo current–voltage characteristics and determined photocurrent action spectra. We confirmed the p-type semiconductor property of DE2 thin films evidenced by the formation of the Schottky barrier at the DE2/Al interface. We further found a relatively high incident photon to electron conversion efficiency comparable to that of metal phthalocyanine thin films in devices having the same structure. These results demonstrate that DE2 thin film is a candidate for a photocarrier-generating material in organic solar cells.

Silica membranes were prepared by chemical vapor deposition using oxygen and tetramethoxysilane (TMOS), phenyltrimethoxysilane (PTMS), or dimethoxydiphenylsilane (DMDPS) as the silicon source at 873 K. The pore size was successfully controlled by changing the number of phenyl groups on the silicon precursor. The permeation test of several gases revealed that larger pores were formed upon increasing the number of phenyl groups on the source. The DMDPS-derived membrane showed excellent hydrogen permeance at 573 K of the order of 10 −6 mol m −2 s −1 Pa −1 , and a high hydrogen/sulfur hexafluoride permselectivity of over 6800, and this excellent performance was constant for 266 h even under moist conditions containing steam at 3.4 kPa and 573 K. Characterization with XPS indicated that the DMDPS-derived membrane was thinner than the TMOS membrane. Additionally, the bond energies of the silicon sources were estimated based on quantum chemical calculations with the CBS-QB3 method. The results showed a strong tendency for gas-phase conversion of TMOS or PTMS to dimethoxysilanone, (MeO) 2 Si O, and DMDPS to methoxyphenylsilanone, Ph(MeO)Si O, transient intermediates that act as major precursors. It was suggested that whether the intermediate contained phenyl groups greatly influenced the enlargement of pore size of the silica membrane.

Large-scale, self-supporting ultrathin films composed of an elastomeric polyacrylate network interpenetrated by a silica (SiO2) network were synthesized and characterized. The organic network was first photopolymerized and the silica structure was subsequently developed in situ in the preformed organic gel. Composition and morphology of the hybrid interpenetrated network (IPN) nanofilms were characterized by infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy and compared with the case of zirconia (ZrO2) hybrid IPN reported earlier. Young modulus, ultimate tensile strength, and ultimate tensile elongation were determined for different organic/inorganic molar ratios and give some insights on how the composition of the nanofilms influence their robustness and self-supporting properties.

In this study, cross-linked materials were prepared using the branched macromonomer with different CL/LA molar ratios, and feasibility studies for tissue engineering were carried out. The thermal and mechanical properties of these materials depended on the CL/LA compositions; however, there was no change in the wettability of each material. The HeLa cells adhesion and growth on the CL-LA7030c were equal to that on the commercially available polystyrene dish. The protein absorption experiment using the FBS proteins revealed that the materials with well-grown cells showed better adhesion of the proteins. [photo: see text]

The electronic structures of a series of DNA nucleobases and their dinucleotides were investigated by N 1s X-ray absorption, X-ray photoemission, and resonant X-ray emission spectroscopy. Resonant X-ray emission spectra of the guanine base and its dinucleotide indicate that it has a weak structure at the lowest binding energy; at this energy, it isolates from the main valence band and forms the HOMO state. This indicates that the HOMO state is localized in the guanine base, as claimed by valence and core photoemissions and expected from theoretical predictions. In addition, the XAS and XES profiles of the guanine dinucleotide indicate that disruption of the aromatic character of the six-membered ring results in the localization of the pi state at the imine (-N=) site of the guanine base; this may favor charge transfer among stacked guanine bases and further influence the conductivity of DNA.

In this study, magnetite nanoparticles conjugated with the temperature-responsive N-isopropylacrylamide-based functional copolymer were prepared. Observations using a transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS) spectral measurements proved that the surrounding polymer layers bind to the magnetite surfaces. The particles showed a very sensitive temperature-responsive behavior, which was confirmed by particle size analysis and investigation of retention in a hydrophobic octadecylsilane (ODS)-modified column. In the magnetic field that was induced by an alternating electric current, the nanoparticles also demonstrated a sensitive temperature-responsive behavior and this result meant that the temperature-responsive polymer layer could absorb the heat induced in the magnetite cores. The temperature-responsive magnetite nanoparticles could show effective aggregation formation or hydrophobic interaction in response to an alternating magnetic field. These interesting phenomena would be used for embolization therapy or targeted drug delivery aiming at a cancer treatment.

Identification of small-molecule ligands for a protein of interest can facilitate the analysis of the protein's functions in biological systems. Small-molecule microarrays have allowed for rapid detection of such ligand-protein interactions in a high-throughput manner, although a label on a protein is needed to observe these interactions. By combining SPR imaging technology with our recently developed photo-cross-linked small-molecule array platform, we developed a novel platform that allows in situ observation of interactions between photo-cross-linked small molecules on gold surfaces and nonlabeled proteins in solution. Interactions of estrogenic and androgenic substances with estrogen receptor alpha were observed using this platform.

Biodegradable polymers such as poly ( l -lactic acid) (PLLA) are widely used to construct cell scaffolds for tissue engineering. We previously reported that cell attachment on a PLLA surface was improved by ion-beam irradiation. In this report, we attempted to characterize the cell-adhesion surface induced by ion-beam irradiation into PLLA by means of X-ray photoemission spectroscopy (XPS), Raman scattering measurement (Raman), and a fluorescence antibody technique. The substrates used were PLLA films; Ar+ ion-beam irradiation was performed at an energy of 50 keV with fluences of 1 × 1014 and 1 × 1015 ions/cm2. The results of XPS and Raman studies indicated the formation of new carbon structures and new functional groups by ion-beam irradiation. The protein adsorption was improved by Ar+ irradiation. We concluded that the cell-adhesion surface was induced as a consequence of production of new functional groups by ion-beam irradiation.