锂离子电池用“三明治”型Si/Fe/Si薄膜负极材料的制备及其性能

采用磁控溅射法在铜箔集流体上沉积得到了具有“三明治”结构的Si/Fe/Si薄膜. 高分辨率透射电镜(HRTEM)和选区电子衍射(SAED)分析表明, 该薄膜为非晶态. 扫描电镜(SEM)和能量散射X射线能谱(EDXS)结果表明, 该薄膜循环前总厚度为3.2 μm, 循环200 周后体积膨胀率为265%. 在1.5-0.005 V(vs Li+/Li)和0.1 mA·cm-2条件下, 该薄膜电极首次吸锂量为1.85 mAh·cm-2, 70周后放锂量达最大值0.84 mAh·cm-2, 200周后放锂量仍维持在0.55 mAh·cm-2, 为最高放锂量的66%. 惰性材料铁的加入一方面提高了薄膜的导电性和电极的面积比容量, 有效抑制了电压滞后效应; 另一方面有效抑制了活性物质硅的体积膨胀, 保持了薄膜较好的循环充、放电性能.     

Membrane potential of a bipolar membrane: the effect of concentration perturbation of the intermediate phase around a certain value

A new model of a sandwich-type bipolar membrane potential was constructed by assuming the potential behavior of a bipolar membrane as a combination of each layer potential between two different states, i.e. the different concentrations of the bulk solution. Hence, we introduced the coion exclusion parameter that is derived from the Donnan equilibrium as a combinatorial function, which combined all the potential equations involved in our system. We assumed that the existence of the intermediate phase due to its volume would allow the Donnan equilibrium to play an important role, i.e. the vanishing of the coion exclusion effect of the membrane layer facing the bulk solution phase in high concentration. Sandwich-type bipolar membranes, which consist of a cation- (K-501) and an anion-exchange layer (A-501) were used in this study. A series of concentration perturbations of the intermediate phase was performed to examine the membrane potential behavior of the bipolar membrane experimentally. The experimental results showed a good agreement with the theoretical results, which led to the conclusion that explained the contribution of the intermediate phase to the membrane potential behavior through its volume and electrochemical properties.     

Sandwich-type Uranium-Substituted of Bismuthotungstate: Synthesis and Structure Determination of [Na(UO2)2(H2O)4(BiW9O33)2]13?

The sandwich-type [Na(UO₂)₂(H₂O)₄(BiW₉O₃₃)₂]¹³⁻ uranium (VI) has been synthesized by reacting the trivacant species of B-α-[BiW₉O₃₃]⁹⁻ with and investigated by IR and UV–Vis spectroscopy, and elemental analysis. The X-ray single crystal analysis was carried out on Na₁₃[Na(UO₂)₂(H₂O)₄(BiW₉O₃₃)₂] · 33H₂O (I) which crystallizes in the orthorhombic system, space group Pna2₁ with a = 33.8454(19) ?, b = 21.1484(12) ?, c = 13.2403(7) ?, α = 90°, β = 90°, γ = 90°, and Z = 4. The polyanion consists of two lacunary B-α-[BiW₉O₃₃]⁹⁻ groups which sandwich two uranyl cations and one sodium cation. The uranium atoms adopt distorted pentagonal–bipyramidal coordination, achieved by two equatorial bonds to each BiW₉O₃₃ unit and one external water ligand. The coordination of each uranium atom is evident by the shift of ν_as(W–O_b–W) and ν_as(Bi–O) stretching vibrational bonds. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Subordination properties for meromorphic multivalent functions associated with the multiplier transformation

The purpose of the present paper is to obtain some sandwich-type theorems, which are combined by subordination and superordination preserving properties associated with a certain family of multiplier transformations for meromorphic multivalent functions in the punctured open unit disk.     

Disposable Sandwich‐type Electrochemical Sensor for Selective Detection of Glucose Based on Boronate Affinity

A disposable sandwich‐type electrochemical sensor for selective detection of glucose was established. The primary receptor, 3‐aminophenylboronic acid was grafted covalently onto the surface of screen‐printed carbon electrodes through an in situ‐generated diazo‐reaction. Glucose was first captured by boronic acid group on the electrode, followed by captureing an electroactive ferroceneboronic acid (FcBA) as the secondary receptor to form bidentate glucose‐boronic complex. Electrochemical impedance spectroscopy was applied to characterize the construction of sandwich‐type disposable sensor. In the sandwich assay, current response of captured FcBA on the electrode was dependent on the concentration of glucose. The sandwich assay showed higher selectivity for glucose than that for fructose, mannose, galactose and other electroactive interferences including uric acid, ascorbic acid and dopamine, and exhibited a dynamic concentration range of glucose from 0.5 to 20.0 mmol L⁻¹. The disposable sensor demonstrated a good reproducibility with 2.2 % relative standard deviation (RSD). In addition, the disposable glucose sensor was used in detection of the trace glucose in the clinical urine samples.     

A sandwich-type DNA biosensor based on electrochemical co-reduction synthesis of graphene-three dimensional nanostructure gold nanocomposite films

A novel electrochemical DNA biosensor based on graphene-three dimensional nanostructure gold nanocomposite modified glassy carbon electrode (G-3D Au/GCE) was fabricated for detection of survivin gene which was correlated with osteosarcoma. The G-3D Au film was prepared with one-step electrochemical coreduction with graphite oxide and HAuCl₄ at cathodic potentials. The active surface area of G-3D Au/GCE was 2.629 cm², which was about 3.8 times compared to that of a Au-coated GCE under the same experimental conditions, and 8.8 times compared to a planar gold electrode with a similar geometric area. The resultant nanocomposites with high conductivity, electrocatalysis and biocompatibility were characterized by scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). A “sandwich-type” detection strategy was employed in this electrochemical DNA biosensor and the response of this DNA biosensor was measured by CV and amperometric current–time curve detection. Under optimum conditions, there was a good linear relationship between the current signal and the logarithmic function of complementary DNA concentration in a range of 50–5000 fM with a detection limit of 3.4 fM. This new biosensor exhibited a fast amperometric response, high sensitivity and selectivity and has been used in a polymerase chain reaction assay of real-life sample with a satisfactory result.     

A novel 2D layer structure constructed from sandwich-type transition metal substituted tungstates and nickel coordination fragments: {[Ni(enMe)2]2[Ni(enMe)2(H2O)]2[As2W18Ni4(enMe)2O68]}·2H3O·2H2O

A novel polyoxometalate {[Ni(enMe)₂]₂[Ni(enMe)₂(H₂O)]₂[As₂W₁₈Ni₄(enMe)₂O₆₈]}·2H₃O·2H₂O (1) (enMe = 1,2-propylenediamine) has been synthesized and characterized, which is the first high-dimensional structure constructed from sandwich-type transition metal substituted tungstates and transition metal coordination groups.     

Structurally original oxathioethers macrocycles containing an exocyclic double-bond: synthesis,characterization, reactivity,and coordination

New oxathioethers macrocycles have been synthesized and characterized. Each macrocycle consists in structurally defined ether and thioether moieties and an exocyclic double-bond (2a–c) or a hydroxymethyl group (3a–c). Macrocycles (2a–c) have been synthesized by reaction of dianions of thioethers diols (1a–c) with 3-chloro-2-chloromethylprop-1-ene. Their hydroboration/oxidation led to corresponding primary alcohols (3a–c). Structures of compounds (2b) and (3a) have been determined by X-ray diffraction. The reactivity of the hydroxyl group allowed the preparation of oxathioethers macrocycles bearing a polyether chain or a benzyl group (4a,b) and the synthesis of new bicyclic sandwich-type compounds (5a,b). The ability of these functionalized macrocycles to coordinate to palladium has been investigated.     

Hydrothermal synthesis and crystal structure of a heteropolyoxotungstate formed by sandwich-type heteropolyanion [Gd(PW11O39)2]11− and reduced [Cu(en)2] + cations

A heteropolyoxotungstate, [Cu(en)₂]₂H₈[Gd(PW₁₁O₃₉)₂] ·?(H₂en)_0.5 ·?3H₂O (1), has been hydrothermally synthesized and characterized by IR, XPS, TGA and single-crystal X-ray diffraction. Compound 1 crystallizes in the triclinic system, space group P 1, with a =?12.651(2) ų, b =?20.559(3) ų, c =?21.729(3) ų, α =?71.379(2), β =?82.829(2), γ =?75.532(2)°, V =?5179.5(14) ų, Z =?2, R ₁ =?0.0702 and ωR ₂ =?0.1479. The heteropolyanion is composed of two monovacant [α-PW₁₁O₃₉]^7? Keggin moieties linked via a Gd atom leading to a sandwich-type structure. The Gd center is in a distorted square antiprismatic coordination environment with eight oxygen atoms, four from each of the two [α-PW₁₁O₃₉]^7?moieties.     

Hydrothermal synthesis and structural characterization of two inorganic–organic composite sandwich-type tungstogermanates

Two new inorganic–organic hybrid polyoxotungstates [enH₂][C₈N₄H₂₂]₃H₂[Co₄(enH)₂(GeW₉O₃₄)₂] · 6H₂O (1) and [Co(en)₃]₂H₆[Co₄(enH)₂(GeW₉O₃₄)₂] · 14H₂O (2) (en = ethylenediamine) have been synthesized by hydrothermal methods and characterized by IR, TG, XRD, XPS, elemental analysis, and single-crystal X-ray analysis. The polyoxoanion frameworks of the two compounds consist of two classical tetra-Co sandwiched polyoxoanions [Co₄(H₂O)₂(GeW₉O₃₄)₂] in which two organic ligands substitute two water molecules. The tetra-Co clusters in 1 and 2 exhibit the familiar structural type of a β-junction at the sites of metal incorporation. Compound 1 is of interest owing to its C₈N₄H₂₀ ligands resulting from the reaggregation of triethylenetetramine which occurs under 160°C.