Loosely coordinating diluted highly concentrated electrolyte toward -60℃ Li metal batteries

Lithium metal batteries(LMBs) promise energy density over 400 Wh kg^(-1).However,they suffer severe electrochemical performance deterioration at sub-zero temperatures.Such failure behavior highly correlates to inferior lithium metal anode(LMA) compatibility and sluggish Li^(+) desolvation.Here,we demonstrate that cyclopentylmethyl ether(CPME) based diluted high-concentration electrolyte(DHCE)enables-60℃ LMBs operation.By leveraging the loose coordination between Li^(+) and CPME,such developed electrolyte boosts the formation of ion clusters to derive anion-dominant interfacial chemistry for enhancing LMA compatibility and greatly accelerates Li^(+) desolvation kinetics.The resulting electrolyte demonstrates high Coulombic efficiencies(CE),providing over 99.5%,99.1%,98.5% and 95% at 25,-20,-40,and-60℃respectively.The assembled Li-S battery exhibits remarkable cyclic stability in-20,and-40℃ at 0.2 C charging and 0.5 C discharging.Even at-60℃,Li-S cell with this designed electrolyte retains> 70% of the initial capacity over 170 cycles.Besides,lithium metal coin cell and pouch cell with10 mg cm^(-2) high S cathode loading exhibit cycling stability at-20℃.This work offers an opportunity for rational designing electrolytes toward low temperature LMBs.

Simulating the Dynamics of Bimetallic Clusters Deposited onto a Surface Using Molecular Dynamics

This paper examines the interface development between a single crystalline Ag matrix and core-shell AgnCom nanoclusters that have been deposited with energies varying between 0.25 eV and 1.5 eV per atom using computer modeling techniques. Clusters undergo deformation as a result of the slowing down;they may also become epitaxial with the substrate and maintain their core-shell structure. A detailed analysis of the effects of the cluster-surface interaction is conducted over a realistic size and energy range, and a model is created to show how clusters accumulate. It is discovered that both the silver shells and the cobalt cluster cores exhibit limited epitaxy with the substrate, and that the contact produced is only a few atomic layers thick. The effect is higher for Ag shells than for Co cores, and it is not very energy dependent.

Third-Order Nonlinear Optical Responses of Bis(15-crown-5)-stilbenes Binding to One-or Two-Alkali Metal Cation(Li^(+),Na^(+)and K^(+))

Bis(15-crown-5)-stilbenes containing crown ether parts have been widely used in a variety of chemical applications,such as cation detectors,because of their ability to selectively bind to alkali metal cations,Bis(15-crown-5)-stilbenes and its derivatives with complexation of one-or two-alkali metal cation(Li^(+),Na^(+)and K^(+))have been theoretically investigat-ed by quantum chemistry methods.The coordination of alkali cations results in partial shrinkage of crown ethers,which directly affected natural distribution analysis charges and molecular orbital energy levels.The number of alkali metal ions has significant effects on absorption spectra and mean second hyperpolarizability.When one alkali metal ion was added to the anticonformer of bis(15-crown-5)-stilbene,the absorption spectra were obvious-ly redshifted and the mean second hyperpolarizability values were slightly increased;while two alkali metal ions were added to bis(15-crown-5)-stilbene,the absorption spectra were ob-viously blue shifted and the mean second hyperpolarizability values decreased.On the other hand,as the radius of the alkali ions increased,the mean second hyperpolarizability values of the compounds increased gradually.It is indicated that the mean second hyperpolarizability value is sensitive to the number and radius of the alkali metal cations,thus the third order nonlinear optical response can be used as a signal to detect the number and type of alkali met-al ions.

Cu-Co bi-metal catalyst prepared by perovskite CuO/LaCoO_3 used for higher alcohol synthesis from syngas

Cu-Co bi-metal catalysts derived from CuO/LaCoO3 perovskite structure were prepared by one-step citrate complexing method, and the structure evolution reaction from CuO/LaCoO3 to Cu-Co2C/La202CO3 under 1-12 pretreatment was investigated by techniques of XRD, TPR and TEM. The results suggest that a much higher dispersion of copper significantly enhanced the reduction of cobalt, and a stronger interaction between copper and cobalt ions in LaCoO3 particles led to the formation of bi-metallic Cu-Co particles in the reduced catalysts and the enrichment of Co on the surface of bimetallic particles. The prepared catalysts were highly active and selective for the alcohol synthesis from syngas due to the presence of copper-modified C02C species.

PO_(4)^(3-)掺杂Bi_(2)O_(2)CO_(3)/Bi^(0)的制备及其可见光催化性能

构建氧空位以及附着金属单质Bi(Bi^(0))是增强半导体材料光吸收性能、促进半导体光生载流子分离的有效方法。通过简单的共沉淀法及氢气热还原成功制备了PO_(4)^(3-)掺杂Bi_(2)O_(2)CO_(3)附着Bi^(0)(Bi-P-BOC)的可见光催化剂,并对其在可见光下催化降解氧氟沙星(OFX)的性能及机理进行了研究。材料表征结果表明BOC随着PO_(4)^(3-)的均匀掺杂,可见光吸收能力增强,表面缺陷增多,比表面积增大。而随着氢气热还原,BOC表面形成Bi^(0)的同时也原位构建了大量的氧空位。可见光催化性能测试表明,Bi-P-BOC可以在180 min内降解约85%的OFX,降解速率为0.013 0 min^(-1),是BOC降解速率的8倍。Bi-P-BOC光催化降解机理表明其具有更好的可见光吸收能力,Bi^(0)以及氧空位的存在促进了光生载流子的分离,h+是其光催化降解过程中的主要的活性氧物种(ROS),此外,^(1)O_(2)和·O_(2)-也对降解有一定贡献。

Bi-phasic Simulation of Metal Injection Moulding:Constitutive Determinations

To predict the segregation effect in metal injection moulding (MIM) injection, a bi-phasic model based on mixture theory is adopted in simulation. An explicit algorithm is developed and realized by the authors, which conducts the simulation to be a cost-effective tool in MIM technology. In case of the bi-phasic simulation, the viscosity behaviours are necessary to be determined for the flows of each phase while only the viscosity of mixture is measurable by tests. It is a crucial problem for application of the bi-phasic simulation of MIM injection. A reasonable method is hence analysed and proposed to determine the viscosity behaviours of each phase. Even though this method may be furthermore modified in the future, it results in the practical simulation of segregation effects with reasonable parameters. The simulation results are compared with the measurements on injected specimens.

A Three-dimensional Porous Metal-organic Framework Based on Cyano Unit and 1,4-Bis(1,2,4-triazol-1-yl)butane(btb):{[Cu_8(btb)_2(CN)_8].3H_2O}_n

The title coordination polymer 1,{[Cu8（btb）2（CN）8].3H2O}n（btb = 1,4-bis（1,2,4-triazol-1-yl）butane）,has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction.Complex 1 crystallizes in monoclinic,space group C2/c with a = 1.2938（3）,b = 1.9422（5）,c = 0.9406（2） nm,β = 121.891（4）°,V = 2.0066（9） nm3,C24H30Cu8N20O3,Mr = 1155.00,Dc = 1.912 g/cm3,μ（MoKα） = 4.209 mm？1,F（000） = 1140,GOF = 1.184,Z = 2,the final R = 0.0634 and wR = 0.1503 for I 2σ（I）.In complex 1,one-dimensional CuCN zigzag chains are linked by triazolyl groups of btb ligands to form two-dimensional networks,which are further bridged by 1,4-butyl moieties of btb ligands to fabricate a three-dimensional order framework,in which one-dimensional ellipsoid-like channels are observed.

An Exploratory Study of Tridentate Amine Extractants: Solvent Extraction and Coordination Chemistry of Base Metals with <i>Bis</i>((1<i>R</i>-benzimidazol-2-yl)methyl)amine

Solvent extraction of base metals using bis((1-decylbenzimidazol-2-yl)methyl)amine (BDNNN) showed a lack of pH-metric separation of the metals. The extraction system was described quantitatively using the equilibria involved to derive the mathematical explanation for the two linear log D vs pHe plots for each metal ion extraction curve, and coordination numbers could also be extracted from the two slopes. The lack of separation was attributed to the absence of stereochemical “tailor making” since the complexes isolated from the reaction of the ligand, bis((1H-benzimidazol- 2-yl)methyl)amine (NNN), with base metals suggested the formation of similar octahedral complex species from spectral and crystal structure evidence. The bis tridentate coordination observed was in agreement with information extracted from the extraction data. This investigation opens up an opportunity and an approach for the evaluation of amines as extractants but cautions against tridentate ligands.

Phase Behaviors in Bi-phase Simulation of Powder Segregation in Metal Injection Molding

Powder segregation induced by mold filling is an important phenomenon that affects the final quality of metal injection molding （MIM）. The prediction of segregation in MIM requires a bi-phase flow model to describe distinctly the flows of metallic powder and polymer binder. Viscous behaviors for the flows of each phase should hence be determined. The coefficient of interaction between the flows of two phases should also be evaluated. However, only viscosity of the mixed feedstock is measurable by capillary tests. Wall sticking is supposed in the traditional model for capillary tests, while the wall slip is important to be taken into account in MIM injection. Objective of the present paper is to introduce the slip effect in bi-phase simulation, and search the suitable way to determine the viscous behaviors for each phase with the consideration of wall slip in capillary tests. Analytical and numerical methods were proposed to realize such a specific purpose. The proposed method is based on the mass conservation between the capillary flows in mono-phase model for the mixed feedstock and in bi-phase model for the flows of two phases. Examples of the bi-phase simulation in MIM were realized with the software developed by research team. The results show evident segregation, which is valuable for improving the mould designs.

Bi掺杂对溶胶-凝胶法制备Cu_(2)ZnSnS_(4)薄膜性能影响的研究

Cu_(2)ZnSnS_(4)(CZTS)薄膜太阳电池因其具有较佳带隙、组成元素丰富、理论转换效率高等优点,而被广泛研究。采用溶胶-凝胶法制备了Bi掺杂的CZTS薄膜,研究了Bi掺杂量对薄膜的微观形貌、物相结构和光电性能的影响。研究结果表明,所制备的薄膜为锌黄锡矿结构的CZTS。Bi元素的掺入对薄膜形貌影响很大,晶粒尺寸先增大后减小,薄膜更致密、更均匀。随着Bi掺杂含量增加,CZTS薄膜的光学带隙呈上升趋势,光电流响应先增大后减小。当Bi掺杂浓度为1%时,CZTS薄膜综合性能最佳。

NiAl催化剂催化5-羟甲基糠醛加氢制备2,5-二羟甲基四氢呋喃

[目的] 5-羟甲基糠醛(HMF)是最重要的生物质基平台化学品之一,可以通过催化加氢途径制备许多高附加值化学品.本文为设计在更加温和的条件下达到高效催化HMF加氢的非贵金属催化剂进行了一系列研究.[方法]通过尿素共沉淀法制备了一种NiAl催化剂,考察了NiAl催化剂催化HMF加氢制备2,5-二羟甲基四氢呋喃(BHMTHF)的性能,并利用X射线衍射(XRD)、氢气程序升温还原(H_(2)-TPR)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、氨气程序升温脱附(NH_(3)-TPD)、X射线光电子能谱(XPS)等表征方法系统地研究了不同Ni/Al比、不同煅烧温度和还原温度对催化剂理化性质的影响.[结果] Ni和Al的投料原子比为3∶1,在350℃下煅烧、650℃下还原制备的催化剂Ni_(3)Al-350-650在100℃、氢气压力2.5 MPa的条件下反应1 h,HMF的转化率和BHMTHF产率分别高达99.5%和87.5%.过高的Ni/Al比制备的催化剂比表面积较小,导致暴露的活性位点较少从而降低了催化活性,通过煅烧温度可以调节NiAl催化剂的可还原性.[结论]本研究实现了在温和条件下HMF的高效催化加氢转化.该结果可为用于HMF定向转化的非贵金属催化剂的设计提供参考.

Doping dependent metal to insulator transition in the(Bi,Pb)-2212 system:The evolution of structural and electronic properties with europium substitution

The present work investigates the effect of europium substitution on the （Bi, Pb）-2212 system in the concentration range 0.5 ≤ x ≤1.0. Phase analysis and lattice parameter calculations on the powder diffraction data and the elemental analysis of EDX show that the Eu atoms are successfully substituted into the （Bi, Pb）-2212 system. Resistivity measurements （64-300 K） reveal that the system exhibits superconductivity at x ≤ 0.5 and semiconductivity at x 〉 0.5. With the complete suppression of superconductivity which is known to be a quasi-two dimensional phenomenon in these materials, a metal to insulator transition takes place at x = 0.6 and the predominant conduction mechanism is found to be variable range hopping between localized states, resulting in macroscopic semiconducting behaviour. The results of electrical and structural properties of the doped （Bi, Pb）-2212 compounds suggest that the decrease of charge carrier concentration and the induced structural disorder are the more effective and dominant mechanisms in the origin of the metal to insulator transition and suppression of superconductivity due to Eu substitution at its Sr site.

Synthesis,Crystal Structure and Blue Photoluminescence of a Metal-organic Framework Constructed from Triangular [Zn_3(μ_3-OH)] Clusters with Bis(tetrazole)amine Ligands

A new metal-organic framework, {Zn[Zn3（BTA）3（μ3-OH）（H2O）3]2}n 1, has been synthesized under hydrothermal reaction of ZnCl2 and bis（5-tetrazolyl）amine （H2BTA）, and characterized by elemental analysis, FT-IR, Raman spectrum, X-ray single-crystal diffraction, TGA and photoluminescence measurements. Compound 1 crystallizes in the trigonal system, space group P-3cl, a = 13.667（3）, c = 12.981（3） A, V = 2099.6（8） A3 and Z = 2. The BTA2- ligand in 1 assumes theμ3 tetradentate mode with both 1,2- and 1,4-tetrazole bridges, generating an unusual 2-D layer, in which the [Zn3（μ3-OH）] triangular motifs act as three-connecting nodes and the mononuclear Zn atoms as six-connecting nodes that are inter-linked by organic ligands. Adjacent 2-D metal-organic layers are linked by strong hydrogen bonds to form a novel 3-D supramolecular framework. Complex 1 exhibits blue fluorescence emission in the solid state at ambient temperature.

Dioxygen Affinities and Biomimetic Catalytic Oxidation Performance of Transition-metal Complexes with Unsymmetrical Bis-Schiff Bases

The oxygenation constants and thermodynamic parameter (ΔHo, ΔSo) of Co (II) complexes with unsymmetrical bis-Schiff baeses were measured and their Mn(III) complexes as models of mimicking monooxygenase were employed to catalyze epoxidation of styrene. The effect of substituent R in a salicylidene of ML1~ML4 [ M = Co (II), Mn (III)Cl ] on the dioxygen affinities and biomimetic catalytic oxidation performance were also investigated. Among them, the MnL4Cl containing a pendant benzoaza crown ether ring showed highest conversion and selectiviy up to 54.9% and 96.9% respectively.

Dual-function protective layer for highly reversible Zn anode

The thermodynamic instability of zinc anodes in aqueous electrolytes leads to issues such as corrosion,hydrogen evolution reactions(HER), and dendrite growth, severely hindering the practical application of zinc-based aqueous energy storage devices. To address these challenges, this work proposes a dualfunction zinc anode protective layer, composed of Zn-Al-In layered double oxides(ILDO) by rationally designing Zn-Al layered double hydroxides(Zn-Al LDHs) for the first time. Differing from previous works on the LDHs coatings, firstly, the ILDO layer accelerates zinc-ion desolvation and also captures and anchors SO_(4)^(2-). Secondly, the in-situ formation of the Zn-In alloy phase effectively lowers the nucleation energy barrier, thereby regulating zinc nucleation. Consequently, the zinc anode with the ILDO protective layer demonstrates long-term stability exceeding 1900 h and low voltage hysteresis of 7.5 m V at 0.5 m A cm^(-2) and 0.5 m A h cm^(-2). Additionally, it significantly enhances the rate capability and cycling performance of Zn@ILDO//MnO_(2) full batteries and Zn@ILDO//activated carbon zinc-ion hybrid capacitors.This simple and effective dual-function protective layer strategy offers a promising approach for achieving high-performance zinc-ion batteries.

基于多区多求解器的金属-介质复合目标电磁散射特性分析

在导弹类金属-介质复合目标电磁散射特性求解过程中,采用常规迭代求解方法存在难以收敛以及内迭代边界积分区域重复求解的问题。针对该问题,在传统有限元边界积分区域分解法(finite element boundary integral domain decomposition method,FE-BI-DDM)的基础上,采用了更为灵活的多区多求解器的方法(multi domain multi solver method,MDMSM)。该方法对导弹类金属-介质复合目标中难以收敛的金属区域,使用快速直接求逆的方法求解,由于可以使用独立的网格模型进行电磁建模,避免了内迭代部分的模型重复建立过程,从而大幅减少了整体模型求解时间。实验结果表明:所提方法可以在相同计算精度的条件下,以不过多增加内存空间为前提,大幅缩短了导弹类目标的金属-介质复合模型的电磁求解时间。该方法为开展导弹类目标特性分析提供了一条可行的技术途径。

Spectral, Thermal and Antibacterial Studies for Bivalent Metal Complexes of Oxalyl, Malonyl and Succinyl-bis-4-phenylthiosemicarbazide Ligands

The thermogravimetry (TG) and derivative thermogravimetry (DTG) have been used to study the thermal decomposition of some oxalyl (H4OxTSC), malonyl (H4MaTSC) and succinyl-bis-4-phenyl- thiosemicarbazide (H4SuTSC) ligands and their metal complexes using Horowitz-Metzger (HM) and Coats-Redfern methods. The kinetic thermodynamic parameters such as: E*, ΔH*, ΔS*and ΔG* are calculated from the DTG curves. The isolated complexes have the general composition [M2(L) (H2O)6], where M=Cu(II), Zn(II), L=MaTSC and M=Co(II), Cu(II) or Sn(II) and L=Su TSC and [M2(L) (H2O)n]·nH2O where M=Cu(II), Co(II) or Sn(II), L=OxTS or Ma TSC. The tested compounds show a good activity against four strains of bacteria Gram negative Escherichia coli, Pseudomonas aeruginosa species and gram-positive Bacillus cereus and Staphylococcus aureus.

Sn-0.3Ag-0.7Cu-xBi低银无铅钎料的润湿性

以Bi为添加剂对低银型Sn-0.3Ag-0.7Cu无铅钎料进行改性,应用SAT—5100型润湿平衡仪对Sn-0.3Ag-0.7Cu-xBi(x=0,1,3和4.5)钎料的润湿性能作了对比分析。结果表明:适量Bi元素的加入可以改善Sn-0.3Ag-0.7Cu钎料合金的润湿性能,且在240℃下Sn-0.3Ag-0.7Cu-3.0Bi无铅钎料具有最佳的润湿性能,在250℃其润湿力达到最大值3.2×10–3N/cm。

Sn-Zn-Bi无铅焊料表面张力及润湿性研究

采用气泡最大压力法对Sn-9Zn-XBi焊料进行了表面张力测试,用平衡法测试焊料的润湿性。结果表明:Bi的添加大大降低了Sn-Zn系焊料熔体的表面张力;然而焊料暴露在空气环境下1min后,表面形成ZnO导致其表面张力增大;Bi的增加提高了焊料在铜片上的润湿力,缩短了润湿时间;Sn-9Zn-XBi焊料润湿力仍低于Sn-40Pb,其原因是焊料–铜界面能偏高。

强磁场对Bi-Mn合金半固态凝固过程中MnBi析出相组织的影响

在Bi 6%Mn合金从高于355℃(升温过程中MnBi化合物磁性转变温度)的固液两相区凝固过程中,研究了MnBi析出相组织在无磁场和强磁场条件下的演化过程。结果表明:在无磁场条件下MnBi析出相形态在340℃(MnBi相顺磁铁磁转变温度)附近发生突变,由较规则的六方块状变为沿ab面长大的不规则片状;10T磁场条件下析出相形态突变的温度提高到355℃左右。另外,10T磁场能够控制析出相晶粒以c轴平行磁场取向、定向聚合和熔合长大,使析出相的最终形态又趋向较规则的六方块状。