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Currently, it is a great challenge to find suitable electrode materials for sodium-ion batteries (SIBs) with large capacity, long cycle life, and high rate capability. Herein, we report a new layered titanate, Na2Li2Ti5O12 (NLT), derived from K2Li2Ti5O12 (KLT) via an ion-exchange method as a SIB anode material. KLT is prepared by a low-temperature solid-state reaction and then transformed into NLT by replacing potassium with sodium in a NaCl solution at room temperature. NLT provides a sodium-ion intercalation voltage at ∼0.5 V versus Na/Na+ and a reversible capacity of 175 mA h g−1 at a current density of 100 mA g−1. It also shows a high sodium-ion diffusion coefficient of 3.0 × 10−10 cm2 s−1, ensuring a high rate capability. For NLT, extremely high discharging rate capability is achieved with a capacity of more than 80 mA h g−1 at a 60 second full discharge and even with 70 mA h g−1 at a 34 second charge. Kinetics analysis based on cyclic voltammogram reveals a typical sodium-ion intercalation behavior in NLT. Furthermore, the first-principle calculation shows a lower migration energy barrier for sodium ions in NLT than that in other layered titanates. These results suggest that NLT is a very promising anode material for high-performance SIBs, especially for fast-charging stable SIBs.

Transition metal phosphides are often studied as hydrogen evolution reaction cathode catalysts, but scarcely as oxygen evolution reaction (OER) anode catalysts for water oxidation. Herein, we report a new amorphous Co0.63Fe0.21P0.16 OER catalyst, which was prepared through a one-step solvothermal process. This catalyst exhibits extraordinary OER catalytic activity in alkaline media and is superior to the state of the art IrO2 in 1.0 M KOH, capable of yielding a current density of 10 mA cm−2 at an overpotential of only 217 mV. This newly achieved high activity outperforms most reported transition metal phosphide catalysts. During the OER, the surface layers of the Co0.63Fe0.21P0.16 nanospheres (200–500 nm) are oxidized, which show the typical Tafel slope of oxides around 40 mV dec−1. The in situ formation of surface Co oxides in the catalysts during the OER along with an optimal doping of Fe are found to be crucial for their remarkable activity. In particular, the metal-rich amorphous phosphide cores, i.e., substrates, probably contribute to OER performance of the catalysts due to their high electrical conductivity. This new type of surface oxidized amorphous transition metal phosphide would provide a new pathway for the design of high-performance OER electrocatalysts.

Highly active and durable bifunctional oxygen electrocatalysts are of pivotal importance for clean and renewable energy conversion devices, but the lack of earth-abundant electrocatalysts to improve the intrinsic sluggish kinetic process of oxygen reduction/evolution reactions (ORR/OER) is still a challenge. Fe-N-C catalysts with abundant natural merits are considered as promising alternatives to noble-based catalysts, yet further improvements are urgently needed because of their poor stability and unclear catalytic mechanism. Here, an atomic-level Fe-N-C electrocatalyst coupled with low crystalline Fe

Background Cocoon abdomen is a relatively rare abdominal disease characterized by the total or partial encasement of the small intestinal by a dense fibro-collagenous membrane. Case presentation We reported an unusual case of idiopathic cocoon abdomen with congenital colon malrotation. Laparotomy and sac release were performed on the patient. The patient was no recurrence 6 months after operation. A literature review was also performed. Conclusion Preoperative diagnosis of abdominal cocoon is difficult. A careful history, physical examination and appropriate radiology may be helpful in making a definitive diagnosis. If conservative treatment can’t relieve symptoms effectively, surgery is currently considered to be important in the management of this disease.

Prussian blue analogs (PBAs) with stable framework structures are ideal cathodes for rechargeable sodium-ion batteries. The chelating agent-assisted coprecipitate method is an effective way to obtain low-defect PBAs that can limit the appearance of too many vacancies and water molecules and achieve an optimized Na-storage performance. However, for this method, the mechanism of chelating agent-assisted synthesis is still unclear. Herein, the synthesis process of nickel hexacyanoferrate (NiHCF) has been investigated by in situ infrared spectroscopy detection. The results show that the chelating agent oxalate slows down the nucleation process and effectively inhibits the formation of the Fe-C≡N-Ni frame in the aging process, producing highly crystallized and low-defect NiHCF samples. High-quality NiHCF presents a high specific capacity of 86.3 mAh g

Metal-organic frameworks (MOFs), such as Prussian blue and its analogues (PB and PBAs) with open frameworks have attracted tremendous attentions as cathode materials for sodium-ion batteries, owing to their simple method of synthesis and high theoretical specific capacity. In this study, core-shell-structured PBAs are prepared by an in situ self-assembly method. Owing to the advantages of both constituents, the as-prepared core-shell PBAs show excellent rate and cycling electrochemical properties through a dual-level-controlled charge-discharge depth mechanism. It delivers a specific capacity of 104.3 mAh g-1 at 0.1 C, as well as a remarkably enhanced cycle performance, giving 88.3 % of its initial capacity over 1000 cycles at 300 mA g-1 . In particular, the coating strategy described herein could be extended to other MOF materials, leading to wider application in energy storage.

The commercialization of proton exchange membrane fuel cells (PEMFCs) relies on highly active and stable electrocatalysts for oxygen reduction reaction (ORR) in acid media. The most successful catalysts for this reaction are nanostructured Pt-alloy with a Pt-skin. The synthesis of ultrasmall and ordered L1

We are presenting a sol-gel method for building novel nanostructures made of nanosized F-doped Na

Manganese dioxide has been recognized as the ideal cathode for the aqueous zinc ion batteries (ZIBs). Nevertheless, the poor conductivity and infinite relative volume changes limit its further practical applications. Herein, we developed a promising cathode design by ball milling of electrolytic manganese dioxide (MnO2) in the presence of graphite nanosheets. MnO2/graphite hybrids with the increase of contact surface and interfacial interaction are beneficial to construct an interfacial 3D conductive network and improve the inherent stability, which achieve the minimum volume change. As expected, the rate and cycling performance of MnO2/graphite hybrids (230 mAh g−1 at 0.1 A g−1, 80 mAh g−1 at 1 A g−1, 80.8% after 1000 cycles at 1 A g−1) are better than that of MnO2 (113 mAh g−1 at 0.1 A g−1, 24 mAh g−1 at 1 A g−1, 51.2% after 1000 cycles at 1.0 A g−1). The reduced volume change during charging/discharging can be observed via in situ optical observations. Furthermore, the Zn ion battery delivers higher energy density of 247 Wh kg−1 at 0.27 kW kg−1 and higher power density of 11.78 kW kg−1 at 78 Wh kg−1. Our work demonstrates the successful and large-scale conversion of industrial electrolytic manganese dioxide into a high-performance cathode of ZIBs.

Prussian blue analogues (PBAs) have attracted great interests due to their stable and open framework structures as novel electrode materials in rechargeable sodium-ion batteries (SIBs). However, Na+ diffusion within electrode materials not only relates to many confined spaces formed by lattice frameworks for Na-ion storage but also highly involves with Na+ migration channel generated by lattice periodic arrangement. In this work, the correlation between PBAs crystallinity and Na+ insertion/extraction properties were systematically investigated. High-crystallized nickel hexacyanoferrate (NiHCF-h) exhibits a fast Na-ion migration process with a high diffusion coefficient of 8.1 × 10−10 cm−2 s−2, and a high capacity retention of 73.7% at 4.25 A g−1. Even crystal size is six times larger than low-crystallized nickel hexacyanoferrate (NiHCF-l), the high-crystallized NiHCF-h shows a faster Na+ insertion/extraction process. The basic structural characterization and pair distribution function (PDF) analysis show that NiHCF-h has a long-range lattice periodicity, enabling Na ions transfer more easily through migration channels. This demonstrates that the crystallinity of PBAs is an extremely important factor in ionic migration process, even with proved vacancies and H2O molecules in PBAs framework structure.

Rechargeable and affordable aqueous zinc-ion batteries (ZIBs) with high energy density are needed for large-scale energy storage systems. However, the development of ZIBs has stagnated due to the lack of stable high-capacity cathode materials. Here, a typical spinel ZnV2O4 has been investigated as a ZIB cathode, and a significant electroactivation reaction was observed during the initial electrochemical cycles. After electroactivation, ZnV2O4 exhibits a high reversible capacity of 312 mAh g−1 and retains a capacity of 206 mAh g−1 over 1000 cycles at a high rate of 10 C. The electroactivation process was then analyzed via in-situ XRD, ex-situ PDF, ex-situ HADDF-STEM, ex-situ XPS, and various electrochemical measurements. The electroactivation enhances the surface electrochemical reaction with self-adaptive adjustment of the lattice structure. This guarantees outstanding electrochemical performance. The encouraging results deepen our understanding of rechargeable aqueous batteries and offer insight into the design of high-performance electrode materials for rechargeable aqueous ZIBs.

Lithium-sulfur (Li–S) battery has aroused intensive attention due to its intrinsicly high capacity and energy density. However, the sluggish kinetics of lithium polysulfide (LiPS) redox conversion and shuttle effect severely damage the sulfur utilization, rate performance, and cycling stability of Li–S batteries. In this work, we report that Ru-doping induced phase transformation from MoP to Mo4P3 (Ru–Mo4P3) could significantly facilitate the electrocatalytic conversion of LiPS. When Ru–Mo4P3 nanoparticles (NPs) are decorated on hollow carbon spheres (HCS), the S/HCS-Ru-Mo4P3 electrode delivers high reversible capacities of 1178 mAh g−1 and 660 mAh g−1 at 0.5C and 4C in Li–S battery, respectively. The rate performance of the developed S/HCS-Ru-Mo4P3 is among the best of the reported transition metal phosphide cathodes for Li–S batteries. When the S loading is as high as 6.6 mg cm−2, S/HCS-Ru-Mo4P3 retains a reversible areal capacity of 5.6 mAh cm−2 after 50 cycles, higher than that of the commercial Li-ion battery (4 mAh cm−2). The excellent Li–S battery performance can be attributed to the intrinsically active Ru–Mo4P3 phase combining with hollow carbon structure, which significantly facilitates the electrocatalytic conversion and entrapment of LiPS.

Highly active and durable bifunctional oxygen electrocatalysts are of pivotal importance for clean and renewable energy conversion devices, but the lack of earth-abundant electrocatalysts to improve the intrinsic sluggish kinetic process of oxygen reduction/evolution reactions (ORR/OER) is still a challenge. Fe-N-C catalysts with abundant natural merits are considered as promising alternatives to noble-based catalysts, yet further improvements are urgently needed because of their poor stability and unclear catalytic mechanism. Here, an atomic-level Fe-N-C electrocatalyst coupled with low crystalline Fe3 C-Fe nanocomposite in 3D carbon matrix (Fe-SAs/Fe3 C-Fe@NC) is fabricated by a facile and scalable method. Versus atomically FeNx species and crystallized Fe3 C-Fe nanoparticles, Fe-SAs/Fe3 C-Fe@NC catalyst, abundant in vertical branched carbon nanotubes decorated on intertwined carbon nanofibers, exhibits high electrocatalytic activities and excellent stabilities both in ORR (E1/2 , 0.927 V) and OER (EJ=10 , 1.57 V). This performance benefits from the strong synergistic effects of multicomponents and the unique structural advantages. In-depth X-ray absorption fine structure analysis and density functional theory calculation further demonstrate that more extra charges derived from modified Fe clusters decisively promote the ORR/OER performance for atomically FeN4 configurations by enhanced oxygen adsorption energy. These insightful findings inspire new perspectives for the rational design and synthesis of economical-practical bifunctional oxygen electrocatalysts.

NaTi

Structural isomerism of colloidal semiconductor nanocrystals has been largely unexplored. Here, we report one pair of structural isomers identified for colloidal nanocrystals which exhibit thermally-induced reversible transformations behaving like molecular isomerization. The two isomers are CdS magic-size clusters with sharp absorption peaks at 311 and 322 nm. They have identical cluster masses, but slightly different structures. Furthermore, their interconversions follow first-order unimolecular reaction kinetics. We anticipate that such isomeric kinetics are applicable to a variety of small-size functional nanomaterials, and that the methodology developed for our kinetic study will be helpful to investigate and exploit solid–solid transformations in other semiconductor nanocrystals. The findings on structural isomerism should stimulate attention toward advanced design and synthesis of functional nanomaterials enabled by structural transformations., Few structural isomers of colloids, with identical masses but different structures, have been identified. Here, the authors observe an interesting example of structural isomerism in a pair of semiconductor magic-size clusters, which reversibly transform between one another with first-order unimolecular reaction kinetics.

A novel solid sodium-ion conductor, Na

Li-S battery technology, with high theoretical capacity and energy density, has drawn much attention in recent years as a possible replacement for current Li-ion battery technologies. A major drawback of Li-S batteries is a severe capacity fading effect which, to a large extent, stems from the dissolution and diffusion of lithium polysulfides (LiPS) that are formed during both charge and discharge cycles. The self-discharge caused by the LiPS migration during the charge process (the so-called "shuttle effect") often leads to the capacity decay of Li-S batteries. Herein, hollow structured metal oxide (Co3O4, Mn2O3, and NiO) submicro-spheres are prepared by a novel method and employed as efficient LiPS immobilizers. These Li-S batteries, based on the developed metal oxide spheres, possess outstanding rate capability and cycling stability. The best performing S/C/Co3O4 electrode delivers excellent cycling stability with only a 0.066% capacity decay per cycle during 550 cycles. Moreover, its discharge capacity is as high as 428 mA h g-1 at a 3C rate which is far superior to that of bare S/C (115 mA h g-1) at 3C. The fast kinetics of the electrocatalytic conversion of LiPS on the developed Co3O4 electrode and its unique hollow structure are the key factors that lead to its outstanding performance as a Li-S battery cathode material.

A facile H2 O2 oxidation treatment to tune the properties of metal disulfides for oxygen evolution reaction (OER) activity enhancement is introduced. With this method, the degree of oxidation can be readily controlled and the effect of surface S residues in the resulted metal (oxy)hydroxides for the OER is revealed for the first time. The developed NiFe (oxy)hydroxide catalyst with residual S demonstrates an extraordinarily low OER overpotential of 190 mV at the current density of 10 mA cm-2 after coupling with carbon nanotubes, and outstanding performance in Zn-air battery tests. Theoretical calculation suggests that the surface S residues can significantly reduce the adsorption free energy difference between O* and OH* intermediates on the Fe sites, which should account for the high OER activity of NiFe (oxy)hydroxide catalysts. This work provides significant insight regarding the effect of surface heteroatom residues in OER electrocatalysis and offers a new strategy to design high-performance and cost-efficient OER catalysts.

The Li-ion conductor “Li6.5La3Zr1.5Ta0.5O12” (LLZT) with garnet structure is prepared by solid-state reaction in an alumina crucible; its stability in water is investigated at room temperature. A Li+/H+ exchange is characterized by TGA, 7Li and 27Al MAS NMR, neutron diffraction, and TEM. In water, Li+/H+ exchange leads to a new garnet oxide “Li6.5 − xHxLa3Zr1.5Ta0.5O12” (H-LLZT) with space group Ia–3d; the lattice parameter of H-LLZT is increased by the exchanged protons. Both LLZT and a grain boundary phase LiAlO2 are unstable in water. The exchanged protons in H-LLZT displace Li from the octahedral sites bridging the 24d tetrahedral sites; they form a strong O H bond that distorted the site. The amorphous phase LiAlO2 in the grain boundary dissolves on exposure to water, which inhibits Li-ion transport across the grain boundary.

Double-perovskite Sr-deficient Sr 2− x MgMoO 6− δ ( x = 0–0.15) samples were prepared via a sol–gel route and evaluated as anode materials for solid-oxide fuel cells. The effects of Sr-site deficiency on lattice structure, electrical conductivity, thermal expansion coefficient (TEC) and electrochemical performance were systematically investigated. It is found that Sr-site deficiency within 0 x x and reaches the maximum at x = 0.10. The Sr-site deficiency also increases the ratio of Mo 6+ , leading to enhanced oxygen vacancy concentration and reduced polarization resistance. With La 0.8 Sr 0.2 Ga 0.83 Mg 0.17 O 3− δ as electrolyte and Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3− δ as cathode, the single cells with Sr 2− x MgMoO 6−δ ( x = 0, 0.05, 0.10 and 0.15) anodes show the maximum power densities of 527, 551, 659 and 573 mW cm −2 , respectively, in H 2 at 800 °C. The x = 0.10 anode exhibits the highest power density due to its high conductivity, low overpotential and good catalytic activity. Single-cell tests indicate the potential application of the deficiency in Sr-site for Sr 2− x MgMoO 6−δ as SOFC anode material.

Here, a P2-type layered Na

Sodium-ion batteries (SIBs) have shown extensive prospects as alternative rechargeable batteries in large-scale energy storage systems, because of the abundance and low cost of sodium. The development of high-performance cathode and anode materials is a big challenge for SIBs. As is well known, TiNb

Although sodium-ion batteries (SIBs) are considered as alternatives to lithium-ion batteries (LIBs), the electrochemical performances, in particular the energy density, are much lower than LIBs. A metal–organic compound, cuprous 7,7,8,8-tetracyanoquinodimethane (CuTCNQ), is presented as a new kind of cathode material for SIBs. It consists of both cationic (CuII↔CuI) and anionic (TCNQ0↔TCNQ−↔ TCNQ2−) reversible redox reactions, delivering a discharge capacity as high as 255 mAh g−1 at a current density of 20 mA g−1. The synergistic effect of both redox-active metal cations and organic anions brings an electrochemical transfer of multiple electrons. The transformation of cupric ions to cuprous ions occurs at near 3.80 V vs. Na+/Na, while the full reduction of TCNQ0 to TCNQ− happens at 3.00–3.30 V. The remarkably high voltage is attributed to the strong inductive effect of the four cyano groups.

In this work, we investigated the systems of (Li, Ca)–O–(Cl, Br) under high pressure and temperature for the synthesis of lithium-rich anti-perovskite (LiRAP) halides. We successfully synthesized Li3 − xCax/2OCl anti-perovskite with x = 0.0, 0.1, 0.2 near 0.5 GPa and temperatures of 400–425 K and Li3OBr anti-perovskite at 3.0 GPa and 450 K. Different from the synthetic route previously reported at ambient pressure, LiA + 2LiOH → Li3OA + H2O, the LiRAP halides under high P–T conditions are formed by dehydration of end-member and Ca-doped halide hydrates with a general formula of Li2x + 1A(OH)2y, where A can be Cl or Br and x must be equal to y. This proposed formula predicts several new halide hydrates including Li3Cl(OH)2, Li5Cl(OH)4, Li3Br(OH)2, and Li5Br(OH)4, indicating that halide hydrates are structurally flexible to accommodate a range of lithium and hydroxide occupancies in the puckered layers of [Li2x + 1(OH)2y+].

Significance Clathrate hydrates have ice-like crystalline structures typically stabled under low-temperature and high-pressure conditions. They are of great importance as potential materials for energy storage and production and carbon dioxide sequestration. Here the first structural refinement data of neon hydrate, to our knowledge, are presented. Both the experimental observations by in situ neutron diffraction and molecular dynamics simulations demonstrate that neon atoms can be enclathrated to form ice II-structured hydrates. The guest Ne atoms occupy the center of ice channels and have substantial freedom of movement owing to the lack of strong bonding between guest molecules and host lattices. The framework of Ne hydrate can be self-stabilized without the encapsulation of guest atoms, which is very special in the hydrate family.

A facile polymer-assisted method is developed to prepare LiNi 2/3 Mn 1/3 O 2 cathode material with polyethylene glycol (PEG400) as the sacrificial template. The structure, morphology, cationic ordering and oxidation state of transition metal ions have been investigated. With assistance of proper amount of PEG, the obtained sample shows improved cyclic performance and rate capability. Initial discharge capacity of 172 mA h g −1 at 0.1 C is attained. The improvement in electrochemical performance can be ascribed to the low Li/Ni cation disorder, good crystallization and uniform morphology promoted by PEG assistance.

Ba2Mg ( B3O6 )( 2 ) (BMBO) is a potential stimulated Raman scattering (SRS) crystal . In this work, a colorless transparent BMBO single crystal with a dimension of 32x23x7 mm(3) has been grown by the Kyropoulos method. A spontaneous Raman spectrum of the crystal was recorded at room temperature. Site group analysis and first-principles calculations were employed to interpret the Raman spectrum . The site group analysis results show that the total lattice modes are 10A(g)+11A(u)+10E(g)+11E(u), of which 10A(g)+10E(g) are Raman -active. The crystal Raman spectrum was computed in CASTEP (Cambridge Sequential Total Energy Package) using a hybrid method combining density functional perturbation theory with the finite displacement method. All of the Raman -active modes have been identified. The internal modes of the B3O6 ring in the crystal give rise to vibrations with Raman shifts above 220 cm(-1); the translations and the librations of the rings, as well as the translations of the Ba2+ cations, give rise to vibrations with Raman shifts below 220 cm(-1). The strongest peak at 645 cm(-1) in the experimental spectrum is assigned to the breathing mode of the B3O6 ring.

Direct methanol fuel cells (DMFCs) hold great promise for applications ranging from portable power for electronics to transportation. However, apart from the high costs, current Pt-based cathodes in DMFCs suffer significantly from performance loss due to severe methanol crossover from anode to cathode. The migrated methanol in cathodes tends to contaminate Pt active sites through yielding a mixed potential region resulting from oxygen reduction reaction and methanol oxidation reaction. Therefore, highly methanol-tolerant cathodes must be developed before DMFC technologies become viable. The newly developed reduced graphene oxide (rGO)-based Fe-N-C cathode exhibits high methanol tolerance and exceeds the performance of current Pt cathodes, as evidenced by both rotating disk electrode and DMFC tests. While the morphology of 2D rGO is largely preserved, the resulting Fe-N-rGO catalyst provides a more unique porous structure. DMFC tests with various methanol concentrations are systematically studied using the best performing Fe-N-rGO catalyst. At feed concentrations greater than 2.0 m, the obtained DMFC performance from the Fe-N-rGO cathode is found to start exceeding that of a Pt/C cathode. This work will open a new avenue to use nonprecious metal cathode for advanced DMFC technologies with increased performance and at significantly reduced cost.

In this work, we present a synthesis approach for nitrogen-doped graphene-sheet-like nanostructures via the graphitization of a heteroatom polymer, in particular, polyaniline, under the catalysis of a cobalt species using multiwalled carbon nanotubes (MWNTs) as a supporting template. The graphene-rich composite catalysts (Co-N-MWNTs) exhibit substantially improved activity for oxygen reduction in nonaqueous lithium-ion electrolyte as compared to those of currently used carbon blacks and Pt/carbon catalysts, evidenced by both rotating disk electrode and Li-O(2) battery experiments. The synthesis-structure-activity correlations for the graphene nanostructures were explored by tuning their synthetic chemistry (support, nitrogen precursor, heating temperature, and transition metal type and content) to investigate how the resulting morphology and nitrogen-doping functionalities (e.g., pyridinic, pyrrolic, and quaternary) influence the catalyst activity. In particular, an optimal temperature for heat treatment during synthesis is critical to creating a high-surface-area catalyst with favorable nitrogen doping. The sole Co phase, Co(9)S(8), was present in the catalyst but plays a negligible role in ORR. Nevertheless, the addition of Co species in the synthesis is indispensable for achieving high activity, due to its effects on the final catalyst morphology and structure, including surface area, nitrogen doping, and graphene formation. This new route for the preparation of a nitrogen-doped graphene nanocomposite with carbon nanotube offers synthetic control of morphology and nitrogen functionality and shows promise for applications in nonaqueous oxygen reduction electrocatalysis for Li-O(2) battery cathodes.

Among transition metal nitrides, tungsten nitrides possess unique and/or superior chemical, mechanical, and thermal properties. Preparation of these nitrides, however, is challenging because the incorporation of nitrogen into tungsten lattice is thermodynamically unfavorable at atmospheric pressure. To date, most materials in the W–N system are in the form of thin films produced by nonequilibrium processes and are often poorly crystallized, which severely limits their use in diverse technological applications. Here we report synthesis of tungsten nitrides through new approaches involving solid-state ion exchange and nitrogen degassing under pressure. We unveil a number of novel nitrides including hexagonal and rhombohedral W2N3. The final products are phase-pure and well-crystallized in bulk forms. For hexagonal W2N3, hexagonal WN, and cubic W3N4, they exhibit elastic properties rivaling or even exceeding cubic-BN. All four nitrides are prepared at a moderate pressure of 5 GPa, the lowest among high-press...

The garnet-related oxide with nominal formula Li 7 La 3 Zr 2 O 12 prepared by the sol–gel method is cubic, space group Ia-3d with lattice parameter a = 12.9720 A at room temperature. The occupancies of three lithium positions (24 d , 48 g , 96 h ) and the position of a small amount of Al 3+ (ca 0.61 wt%) inside the grains were determined by neutron diffraction. The occupancy of the 24 d Li sites was reduced to 36.0% by the Al 3+ occupying the 48 g sites. The bulk and total Li + -ion conductivity at 25 °C was 3.1 × 10 −4 S cm −1 and 1.4 × 10 −4 S cm −1 with an activation energy 0.34 eV in the temperature range 25–160 °C.

In order to investigate the influence of covalent bonding within the garnet framework on the conductivity of Li+ in the interstitial space, the Li+ conductivities in the family of Sn-based compounds Li6La3 SnMO12 (M = Sb, Nb, Ta) have been obtained and are compared with those of Li6La3ZrMO12. Refinement of the neutron diffraction pattern of Li6La3 SnNbO12shows that the interstitial tetrahedral sites (24d ) are about half-occupied and most of the Li in the interstitial bridging octahedral sites are displaced from the center position (48g ). The Sb-based compound has the largest lattice parameter while the Ta-based compound has the highest Li+-ion conductivity of 0.42 10 4 Scm 1.

Single crystals of KCuF 3 have been grown by the solution method. We report neutron diffraction under high pressure up to 8 GPa on a powder sample pulverized from KCuF 3 crystals. The type-A spin ordering structure found in KCuF 3 can be well-explained based on the orbital ordering resolved from this structural study. In comparison with perovskite oxides, the fluoride exhibits a much reduced bulk modulus. Our results also reveal the change of local structural distortion as a function of pressure; the magnitude of Jahn–Teller distortion at ambient condition is dramatically suppressed under high pressure. Extensive comparison of the pressure dependence of the Jahn–Teller perovskite fluoride with that of analogous perovskite oxides has also been made.

The anode TiNb2O7, which has a framework structure for reversible Li insertion, was combined with the spinel LiNi0.5Mn1.5O4 as cathode to give a voltage V ≈ 3.0 V. The anode-limited cell was shown to give a better performance than the cathode-limited cell.

Among transition-metal nitrides, the mononitride γ-MoN with a rock-salt structure has drawn particular attention because it has been predicted to possess excellent mechanical and electronic properties, especially the high superconducting temperature around 30 K. However, synthesis of bulk γ-MoNx with the nitrogen concentration, x, more than 0.5 is still challenging, leading to contradictions on its phase stability and properties. In this work, we formulated a high-pressure synthesis reaction for the formation of single-crystal γ-MoNx with a remarkably high nitrogen concentration value of x ≈ 0.67. This nitride possesses a high asymptotic hardness of ∼24 GPa, which is so far the second hardest among metal nitrides. Impressively, the expected superconductivity is absent in the as-synthesized product. We further performed density functional theory calculations to clarify the structural stability and the absence of superconductivity in stoichiometric γ-MoN. We find that the ground state of γ-MoN is theoretically explored to be a Mott insulator with an antiferromagnetic phase, while a paramagnetic configuration is adopted at the ambient conditions. Such magnetic properties would explain the structural stability and the absence of superconductivity in the as-synthesized γ-MoNx with a high nitrogen concentration.

The cathode materials Li1−x[Ni0.5Mn1.5]O4 prepared by coprecipitation from acetate solution by oxalic acid and annealing at 900 °C in air had the preferred disordered Ni and Mn on the 16d octahedral sites of a spinel F d 3 ¯ m structure. The coprecipitation method provides better crystallinity than the F d 3 ¯ m phase previously obtained by quenching from the melt. Polycrystalline octahedral-shaped particles with smooth surfaces contained trace amounts of a LiyNi1−yO impurity that introduced some Mn(III) into the spinel phase. Half-cells cycled at 0.2 C rate between 3.5 and 4.8 V versus Li exhibited a flat voltage V ≈ 4.7 V with a small step at x ≈ 0.5 and a capacity at room temperature of 130 mAh g−1 that showed no fade after 50 cycles. A small capacity fade was initiated with a cut-off voltage ≥4.9 V; a significant capacity loss between 2 and 5 C cycling rates was reversible to 134 mAh g−1 on returning to 0.1 C after 50 cycles at 10 C between 3.5 and 5.0 V.

Orexins are neuropeptides involved in multiple neurophysiological functions such as reward and motivation. However, it is not clear whether orexins are implicated in sexual motivation. This study aims to evaluate the effects of orexin A and the OX(1)R antagonist SB334867 on unconditioned sexual motivation. Forty-five male Wistar rats are divided into four groups. The four groups are respectively administered intracerebroventricularly with saline, orexin A (1, 10 mu g), 10% DMSO (cyclodextrin) and SB334867 (5, 15 mu g) 10- 15 min before sexual motivation tests. The preference for a receptive female to a male in in open arena with two tethered animals is designated as unconditioned sexual motivation. The results show that orexin A reduces the female preference (reducing time in the female zone and/or increasing time in the male zone). the number of visits for the female zone and the total distance traveled in sexually high-motivated males. SB334867 has no effect on the female preference, the number of visits and the distance traveled in either sexually high-motivated or low-motivated males. Our experiments reveal that centrally administered orexin A attenuates sexual motivation in high-motivated males although endogenous orexin A might not play an important role in the expression of unconditioned sexual motivation. (c) 2008 Elsevier Inc. All rights reserved.

Uniform submicron BiMn 2 O 5 particles were prepared via a facile one-step hydrothermal route at low temperature. Bi(NO 3 ) 3 , MnCl 2 ·4H 2 O and KMnO 4 were used as starting materials; KOH as a pH adjustor and also as a mineralizer. Single-crystalline orthorhombic BiMn 2 O 5 sample with controllable morphology was obtained. The microstructure strongly depends on the molar ratio of the starting materials, KOH concentration and reaction temperature. X-ray photoelectron spectroscopy shows the existence of Mn 4+ state. Magnetic measurement indicates Neel temperature T N at 44 K. The susceptibility above T N obeys the Curie–Weiss law, χ = C /( T − θ ), with θ = −350 K. The effective paramagnetic moment μ eff = 4.66 μ B /Mn, demonstrating the coexistence of mixed Mn 3+ and Mn 4+ valences.