Design,preparation,application of advanced array structured materials and their action mechanism analyses for high performance lithium-sulfur batteries

Lithium-sulfur battery(LSB)has brought much attention and concern because of high theoretical specific capacity and energy density as one of main competitors for next-generation energy storage systems.The widely commercial application and development of LSB is mainly hindered by serious“shuttle effect”of lithium polysulfides(Li PSs),slow reaction kinetics,notorious lithium dendrites,etc.In various structures of LSB materials,array structured materials,possessing the composition of ordered micro units with the same or similar characteristics of each unit,present excellent application potential for various secondary cells due to some merits such as immobilization of active substances,high specific surface area,appropriate pore sizes,easy modification of functional material surface,accommodated huge volume change,enough facilitated transportation for electrons/lithium ions,and special functional groups strongly adsorbing Li PSs.Thus many novel array structured materials are applied to battery for tackling thorny problems mentioned above.In this review,recent progresses and developments on array structured materials applied in LSBs including preparation ways,collaborative structural designs based on array structures,and action mechanism analyses in improving electrochemical performance and safety are summarized.Meanwhile,we also have detailed discussion for array structured materials in LSBs and constructed the structure-function relationships between array structured materials and battery performances.Lastly,some directions and prospects about preparation ways,functional modifications,and practical applications of array structured materials in LSBs are generalized.We hope the review can attract more researchers'attention and bring more studying on array structured materials for other secondary batteries including LSB.

Structural, Optical and Luminescence Properties of ZnO Thin Films Prepared by Sol-Gel Spin-Coating Method： Effect of Precursor Concentration

Transparent zinc oxide（ZnO） thin films are fabricated by a simple sol-gel spin-coating technique on glass substrates with different solution concentrations（0.3-1.2 M） using zinc acetate dehydrate [Zn（CH_3COO）_2·2H_2O] as precursor and isopropanol and monoethanolamine（MEA） as solvent and stabilizer, respectively. The molar ratio of zinc acetate dehydrate to MEA is 1.0. X-ray diffraction, ultraviolet-visible spectroscopy and photoluminescence spectroscopy are employed to investigate the effect of solution concentration on the structural and optical properties of the ZnO thin films. The obtained results of all thin films are discussed in detail and are compared with other experimental data.

THE PREPARATION,STRUCTURE AND PROPERTES OF Sr_(0.5)Ca(0.5)CuO_2

Sr_(0.5)Ca_(0.5)CuO_2 has been synthesized by the solid state reaction.The compound crystallizes in an orthorhombic unit cell,space group D_(2h)^(17)-Cmcm with a=3.444 ,b=16.11 ,c=3.868 .It decomposes shove 1038℃. Sr_(0.5)Ca_(0.5)CuO_2 is s black p-type semiconductor with resistivity 53Ω.cm at room tempersture.

PREPARATION AND CRYSTAL STRUCTURE OF TETRAMETHYLETHENE-BRIDGED DICYCLOPENTADIENYLSAMARIUM (Ⅲ) COMPLEX

(CH_3)_4C_2(C_5H_4)_2Sm(C_5H_5)OC_4H_, Mr=499.4, orthorhombic, Cc2a, a=11.696(6), b=12.539(5), c=29.432(15), V=4316(4)~, Z=8, Dc=1.54g. cm^(-3), μ (MoKα)=27.8cm^(-1), F(000)=2024, R=0.077 for 1833 observed reflections. In the molecule the samarium atom is bonded to three cyclopentadienyl rings and an oxygen of tetrahydrofuran(THF). The three centroids of the cyclopentadienyl rings and the oxygen form a tetrahedral configuration around the Sm(Ⅲ) atom, The average Sm-C(η~) bond distances for the three cyclopentadienyl groups are 2.72(3), 2.76(3), 2.78(8) respectively, and Sm-0 bond is 2.53(1).

INDUCTION—POLYMERIZATION OF PREPARING POLYMERS OF REGULAR STRUCTURE

Induction-Polymerization is a novel method for preparing polymers of regular structure. In the presence of a special macromolecular compound, monomer molecules are aggregeted regularly around one or more growth points and polymerized to polymer of regular structure. Regularity of structure of the polyacrylamide prepared by this means has been verified with electron diffractograms, DSC curve and IR spectrum of the polymer.

Structure and Magnetic Properties of Fe-N Films Prepared by Dual Ion Beam Sputtering

Fe-N films were prepared on Si substrate by dual ion beam sputtering (DIBS). It is found that the crystal structure of the films varies from α-Fe, to ε-Fe2-3N, ε-Fe2-3N +γ-Fe4N, and finally γ'-Fe4N with the increase in substrate temperature (TS). The magnetic properties of the films were investigated by a vibrating sample magnetometer (VSM). The structure of the films is insensitive to the ratios of N2/Ar in main ion source(MIS), and is mainly influenced by the substrate temperature (Ts).

Synthetic and structural chemistry of hexacobalt cluster compounds——Ⅱ. Preparation and structure of Co_6(μ_3-S)_8(Ph_2PCH_2P(O)Ph_2)_6

Co_6(μ_3-S)_8(Ph_2PCH_2P(O)Ph_2)_6, MW=3012.5, space group R, has the hexagonal parameters, a=26.764(10), c=16.979 (10), V=10532.8~3, Z=3. Mo Kα radiation, λ= 0.71069, Dc=1.425 g/cm^3, μ=9.94 cm^(-3), F(000)=4650, R=0.073 and Rw=0.077 for 1965 observed unique reflections with I>3σ(I). The molecular structure consists of a distorted octahed- ral Co_6-core. The Co-Co and Co-S distances fall in the range of 2.805-2.838 and 2.213-2.253, respectively.

Synthetic and structural chemistry of nickel(Ⅱ) complexes containing dithiolato and phosphine ligands Ⅰ. Preparation and crystal structure of Ni_2(PPh_3)_2(edt)_2

A nickel(Ⅱ) complex containing both dithiolato and phosphine ligands, Ni_2(PPh_3)_2(edt)_2 (edt = SCH_2CH_2S^(2-)), has been prepared and characterized by X-ray diffration. The complex crystallizes in the triclinic system, space group P-1, with a = 10.693(3), b = 17.457 (6), c = 10.606 (3)A, α= 102.84(2), β = 96.49 (2), γ = 82.56(3)°; V = 1906.8 A^3; D_c = 1.439g.cm^(-3) for Z=2; the final con- ventional R was 0.052 based on 3338 observed reflections. Nickel atoms are linked by two sulfur atoms from two edt ligands with the Ni--Ni distance of 2.893 A, and each Ni atom is coordinated by one phosphorus atom and three sulfur atoms with a square-planar geometry, where the average: length of Ni--S bond is 2.180 A and Ni--P bond 2.188 A. The UV-Vis and ~1H NMR spectra have also been recorded.

Preparation,Crystal Structure and Fungicidal Activity of N-(5-(benzofuranol-7-oxymethyl)-1,3,4-thiadiazol-2-yl)amide Compounds

A variety of new N-(5-(benzofuranol-7-oxymethyl)-1,3,4-thiadiazol-2-yl)amide compounds(8a-i)were synthesized through four steps from benzofuranol as raw materials.The crystal structure of compound 8a(C17H21N3O3S,Mr=347.43)was measured by X-ray diffraction,which was classified as monoclinic system,Z=4,V=1742.72(8)Å3,Dc=1.324 Mg/m3,F(000)=736,S=1.03,μ=0.21 mm-1,space group P21 with a=9.9177(3),b=8.9519(2),c=19.8679(5)Å,the final R=0.035 and wR=0.105 for 3873 observed reflections(I>2σ(I)).The X-ray structure presented N(3)-H(3)···N(2)and C(6)-H(6)···O(3)intermolecular hydrogen bonds,which acted as an important role in stabilizing the crystal structure.Additionally,preliminary biological assay on compound 8a showed good fungicidal activity in vivo,with the inhibition of 75%against Pseudoperonospora cu-bensis at 200 mg/L.

A cobalt-selenium cluster with triethylphosphine: preparation and structure of Co_6(μ_3-Se)_8(PEt_3)_6·THF

Co_6 (μ_3-Se)_8 (PEt_3)_6·THF, MW=1766.4, space group R, has the trigonal parameters, a=11.890(2)°, α=92.72(2)°, V=1670.4~3, Z=1. Mo Kα radiation, λ=0.71073, Dc=1.749 g/cm^3, μ= 59.18 cm^(-3), F(000)=870, R=0.058 and Rw=0.067 for 1529 observed unique reflections with I>3σ(I). The molecular structure consists of an idealized octahedral Co_6-core. The Co-Co distances fall in the range of 2.909-2.9122.

Improving photoelectrochemical activity of dye sensitized solar cell by a bilayered electrode with an overlayer of mesoporous anatase TiO_2

For better performance of dye sensitized solar cells （DSSCs）, a bilayer structured electrode was constructed by employing a mesoporous anatase TiO2 overlayer above a commercial P25 TiO2 nanoparticles underlayer. The mesoporous anatase TiO2, prepared through a facile surfactant-assisted sol-gel process, possessed large pore size and well inter-connected network structure, both beneficial for dye adsorption and electron transfer. The dye adsorption capability of the mesoporous TiO2 was nearly twice that of the P25 counterpart. In the electrode, the mesoporous TiO2 film enhanced both dye adsorption and lightharvest, to increase photocurrent （Jsc） from 12.32 to 14.78 mA/cm^2. Compared to the single P25 TiO2 film, the synergy of the mesoporous TiO2 and the P25 TiO2 nanoparticle films in the electrode resulted in a 24% improvement in light-to-electricity conversion efficiency （η）. This bilayered electrode provides an alternative approach for further developing a photovoltaic device with better cell performance.

Advances in research of intracranial vascular stent

In recent years, China's population has shown an obvious aging trend. This trend has been accompanied by an increased incidence of cardiovascular disease and death.Intracranial stenting has become an important treatment modality for intracranial vascular disease because it is effective, safe, and widely approved. In this paper,we review the literature concerning the classification, structure, preparation, and performance of intracranial stents. We also summarize problems and future prospects in the context of intracranial stents. This paper will serve as a reference for the future research and development of intracranial stents.