Shin-ichi Nishimura

A 3.8-V earth-abundant sodium battery electrode.

Rechargeable lithium batteries have ushered the wireless revolution over last two decades and are now matured to enable green automobiles. However, the growing concern on scarcity and large-scale applications of lithium resources have steered effort to realize sustainable sodium-ion batteries, Na and Fe being abundant and low-cost charge carrier and redox centre, respectively. However, their performance is limited owing to low operating voltage and sluggish kinetics. Here we report a hitherto-unknown material with entirely new composition and structure with the first alluaudite-type sulphate framework, Na2Fe2(SO4)3, registering the highest-ever Fe3+/Fe2+ redox potential at 3.8 V (versus Na, and hence 4.1 V versus Li) along with fast rate kinetics. Rare-metal-free Na-ion rechargeable battery system compatible with the present Li-ion battery is now in realistic scope without sacrificing high energy density and high power, and paves way for discovery of new earth-abundant sustainable cathodes for large-scale batteries.

Structure of Li2FeSiO4

A large-scale lithium-ion battery is the key technology toward a greener society. A lithium iron silicate system is rapidly attracting much attention as the new important developmental platform of cathode material with abundant elements and possible multielectron reactions. The hitherto unsolved crystal structure of the typical composition Li2FeSiO4 has now been determined using high-resolution synchrotron X-ray diffraction and electron diffraction experiments. The structure has a 2 times larger superlattice compared to the previous beta-Li3PO4-based model, and its origin is the periodic modulation of coordination tetrahedra.

New Lithium Iron Pyrophosphate as 3.5 V Class Cathode Material for Lithium Ion Battery

A new pyrophosphate compound Li(2)FeP(2)O(7) was synthesized by a conventional solid-state reaction, and its crystal structure was determined. Its reversible electrode operation at ca. 3.5 V vs Li was identified with the capacity of a one-electron theoretical value of 110 mAh g(-1) even for ca. 1 μm particles without any special efforts such as nanosizing or carbon coating. Li(2)FeP(2)O(7) and its derivatives should provide a new platform for related lithium battery electrode research and could be potential competitors to commercial olivine LiFePO(4), which has been recognized as the most promising positive cathode for a lithium-ion battery system for large-scale applications, such as plug-in hybrid electric vehicles.

Lithium Iron Borates as High‐Capacity Battery Electrodes

www.MaterialsViews.com C O M Lithium Iron Borates as High-Capacity Battery Electrodes M U N IC By Atsuo Yamada , * Nobuyuki Iwane , Yu Harada , Shin-ichi Nishimura , Yukinori Koyama , and Isao Tanaka A IO N Lithium batteries potentially provide a solution for the future energy economy, which must be based on a low cost, environmentally friendly, and sustainable energy supply. Beyond the limited lithium storage capability of the (PO 4 ) 3 − -based compound, LiFePO 4 (170 mAh/g), which is currently recognized as the most promising electrode material for large-scale application of lithium ion batteries, such as plug-in hybrid vehicles, a compound with the lightest small triangle oxyanion unit (BO 3 ) 3 − , namely LiFeBO 3 , exhibits a larger reversible capacity of ca. 200 mAh/g under moderate current density with surprisingly small volume change of ca. 2%. The inherent activity of Li x FeBO 3 is supported by ab initio calculations and indicates potential as an electrode material with no thermodynamic limitation for approaching a theoretical capacity of 220 mAh/g. Technological evolution over the past few centuries has been fuelled mainly by variations of combustion reactions. However, this has quite possibly contributed to global climate change by the emission of large amounts of carbon dioxide. Therefore, the use of energy must be urgently reconsidered for the sake of future generations. A new energy economy must be based on a low cost and sustainable energy supply. Chemical energy storage using batteries could provide a potential solution, especially if used to store energy obtained from sustainable sources such as wind and solar power. The lithium-ion battery is the most advanced energy storage system that has conquered the portable electronics market, but it is not considered to be sustainable, because expensive cobalt (Clarke No. rank 30) used in the cathode material must be obtained from limited natural resources. [ 1 ] It also involves safety risks, because the cathode functions as a strong oxidizing agent for organic electrolytes. Thus, as a result of compromise, nickel metal hydride (Ni-MH) batteries are presently used in hybrid vehicles. Research in materials science is approaching a solution to the

Ginkgolic Acid Inhibits Protein SUMOylation by Blocking Formation of the E1-SUMO Intermediate

Protein modification by small ubiquitin-related modifier proteins (SUMOs) controls diverse cellular functions. Dysregulation of SUMOylation or deSUMOylation processes has been implicated in the development of cancer and neurodegenerative diseases. However, no small-molecule inhibiting protein SUMOylation has been reported so far. Here, we report inhibition of SUMOylation by ginkgolic acid and its analog, anacardic acid. Ginkgolic acid and anacardic acid inhibit protein SUMOylation both in vitro and in vivo without affecting in vivo ubiquitination. Binding assays with a fluorescently labeled probe showed that ginkgolic acid directly binds E1 and inhibits the formation of the E1-SUMO intermediate. These studies will provide not only a useful tool for investigating the roles of SUMO conjugations in a variety of pathways in cells, but also a basis for the development of drugs targeted against diseases involving aberrant SUMOylation.

High-voltage pyrophosphate cathode: Insights into local structure and lithium-diffusion pathways

Ion-transport paths: combined modeling and neutron diffraction studies provide atomic-scale insights into Li(2)FeP(2)O(7), a material proposed for a new lithium-battery cathode with reversible electrode operation at the highest voltage of all known Fe-based phosphates. The results indicate that Li(+) ions are transported rapidly through a 2D network along the paths shown in green in the picture.

Inhibition of protein synthesis and activation of stress-activated protein kinases by onnamide A and theopederin B, antitumor marine natural products

During the course of screening for the agents that activate transforming growth factor‐β (TGF‐β) signaling cascade, onnamide A and theopederin B, heterocyclic compounds related to mycalamides from a marine sponge, were found to induce plasminogen activator inhibitor‐1 (PAI‐1) promoter‐derived gene expression in Mv1Lu cells. The maximum induction of the PAI‐1 promoter by onnamide A and theopederin B was observed at the concentrations of 50 nM and 2 nM, respectively. These compounds strongly inhibited protein synthesis at the 50% inhibitory concentrations of 30 nM for onnamide A and 1.9 nM for theopederin B, and induced activation of p38 mitogen‐activated protein kinase and c‐Jun NH2‐terminal protein kinase (JNK). Anisomycin, a well‐known inducer of ribotoxic stress that inhibits protein synthesis and activates both p38 kinase and JNK, also activated PAI‐1 gene expression. Furthermore, PAI‐1 expression by onnamide A, theopederin B, and anisomycin was inhibited by SB202190 and SP600125, specific inhibitors of stress‐activated protein kinases. Onnamide A and theopederin B were cytotoxic to a variety of cell lines and strongly induced apoptosis in HeLa cells within 24 h, which was accompanied by the sustained activation of p38 kinase and JNK. These results suggest that onnamide A and theopedirin B trigger a ribotoxic stress‐like response, thereby inducing p38 kinase and JNK activation, the kinase‐dependent PAI‐1 gene expression, and apoptosis. (Cancer Sci 2005; 96: 357–364)

Finite difference simulation of nonlinear waves generated by ships of arbitrary three-dimensional configuration

Abstract A modified marker-and-cell method is developed in order to simulate nonlinear wave making in the near-field of ships of arbitrary three-dimensional (3D) configuration advancing steadily in deep water. The 3D Navier-Stokes equations are solved by a finite difference scheme under proper boundary conditions. Efforts are particularly focused on the treatment of the boundary conditions on the body surface and free surface which have complicated 3D configurations. An orthogonal cell system with more than 70,000 cells is used for the computation of the waves and flow field of ships. The agreement of computational results with experiment is good, and it promises effectiveness for engineering purposes.

Electrochemical Mg2+ intercalation into a bimetallic CuFe Prussian blue analog in aqueous electrolytes

Mg2+ intercalation/deintercalation is achieved by using aqueous electrolytes and Prussian blue analog electrodes. Ex situ X-ray diffraction evidenced the solid solution process of Mg2+ intercalation/deintercalation, while the 57Fe Mossbauer spectroscopy and X-ray absorption near edge structure revealed redox of both Cu and Fe.

Observation of the highest Mn3+/Mn2+ redox potential of 4.45 V in a Li2MnP2O7 pyrophosphate cathode

By exploring the pyrophosphate chemistry for rechargeable Li-ion batteries, we report the synthesis and electrochemical characterization of a Li2MnP2O7 cathode. Easily prepared by conventional solid-state synthesis (at 600 °C), the Li2MnP2O7 displays an Mn3+/Mn2+ redox potential centered at 4.45 V versus lithium. It has registered the highest voltage ever obtained for the Mn3+/Mn2+ redox couple in any Mn-based cathode material. Following the pristine and partially (Mn) substituted Li2FeP2O7 (3.5–3.9 V vs. Li) and Li2CoP2O7 (4.9 V vs. Li), which show the highest Fe3+/Fe2+ and Co3+/Co2+ redox potentials among the known cathode compounds, the highest Mn3+/Mn2+ redox voltage (ca. 4.45 V) in Li2MnP2O7 establishes ‘pyrophosphates’ as a novel family displaying the highest M3+/M2+ redox potentials among all polyanionic compounds. Fundamental study of these pyrophosphates can provide useful insights into design of high-voltage cathode materials.