Novel electrospun polymer electrolytes incorporated with Keggin‐type hetero polyoxometalate fillers as solvent‐free electrolytes for lithium ion batteries

In this study, solvent‐free nanofibrous electrolytes were fabricated through an electrospinning method. Polyethylene oxide (PEO), lithium perchlorate and ethylene carbonate were used as polymer matrix, salt and plasticizer respectively in the electrolyte structures. Keggin‐type hetero polyoxometalate (Cu‐POM@Ru‐rGO, Ni‐POM@Ru‐rGO and Co‐POM@Ru‐rGO (POM, polyoxometalate; rGO, reduced graphene oxide)) nanoparticles were synthesized and inserted into the PEO‐based nanofibrous electrolytes. TEM and SEM analyses were carried out for further evaluation of the synthesized filler structures and the electrospun nanofibre morphologies. The fractions of free ions and crystalline phases of the as‐spun electrolytes were estimated by obtaining Fourier transform infrared and XRD spectra, respectively. The results showed a significant improvement in the ionic conductivity of the nanofibrous electrolytes by increasing filler concentrations. The highest ionic conductivity of 0.28 mS cm^?1 was obtained by the introduction of 0.49 wt% Co‐POM@Ru‐rGO into the electrospun electrolyte at ambient temperature. Compared with solution‐cast polymeric electrolytes, the electrospun electrolytes present superior ionic conductivity. Moreover, the cycle stability of the as‐spun electrolytes was clearly improved by the addition of fillers. Furthermore, the mechanical strength was enhanced with the insertion of 0.07 wt% fillers to the electrospun electrolytes. The results implied that the prepared nanofibres are good candidates as solvent‐free electrolytes for lithium ion batteries. © 2020 Society of Chemical Industry     

β-B-BiW9O33夹心型铋（III）钨酸盐的合成、结构及光谱性质

用常规法合成了一种新的一维链状结构的夹心型多酸Na10{[(Cu(H2O)3)2(WO2)2(BiW9O33)2]}·23.5H2O(1),并对其进行X射线单晶结构分析、元素分析、红外光谱和紫外光谱表征。结果显示,该多酸阴离子属于单斜晶系, P2(1)/n空间群,晶胞参数a=1.2865(26) nm, b=2.52563(49) nm, c=1.62185(41) nm,β=94.03(4)°, V=5.20836(1093) nm3, Z=2, R1=0.0539,ωR2=0.1189, Dc=3.36 g/cm3。紫外光谱在236和293 nm有两个多酸特征的吸收峰。     

[PW12O40]（C2N3H4）3·6H2O的水热合成和晶体结构

在水热条件下,合成出一例新的具有Keggin型结构的杂多酸化合物[PW12O40]（C2N3H4）3·6H2O（1）。利用单晶X-射线衍射分析了该化合物的结构,结果表明该化合物属于三方晶系,R-3空间群,晶胞参数为a=1.79590（3）nm,b=1.79590（3）nm,c=2.43480（5）nm,α=90°,β=90°,γ=120°,V=6.8008（2）nm3,Z=6,R1=0.0458,ωR2=0.1116。在该化合物中,质子化的1,2,4-三氮唑与[PW12O40]3-通过氢键作用形成三维超分子结构。     

Polyoxometalate-Incorporated Supramolecular Self-Assemblies: Structures and Functional Properties

As a family of functional inorganic clusters, polyoxometalates (POMs) were introduced into hybrid self-assemblies with the assistance of the supramolecular interaction with diverse organic cationic molecules, which reinforced both the processibility and functionality of the POMs. This method not only improved the surface properties of the POMs, but also provided excellent amphiphilic building blocks for the construction of advanced self-assembled nanostructures. In this review, we summarize the fundamental aspects of surfactant-encapsulated POMs (SEPs) and the most recent progress in potential applications of SEPs and the related POM-containing systems (hybrids composed of POMs and polymers and other cationic molecules beyond surfactants). The functionalization of such organic/inorganic hybrids in self-assembled systems is also described. Furthermore, perspectives regarding self-assemblies and possible applications of POM complexes with synergetic interactions between organic and inorganic components are outlined.     

Synthesis and anticancer properties of tungstosilicic polyoxometalate containing 5-fluorouracil and neodymium

A novel tungstosilicic polyoxometalate containing 5-fluorouracil and Nd,K26(C4H4FN2O2)8Nd(SiW11O39)4·SH2O(FNSW)was synthesized and its structure was characterized by using elemental analysis,FT-IR spectra,X-ray powder diffraction,UV-vis spectra and TG.The results indicated that the compound FNSW had Keggin structure of heteropolyanion and ring structure of 5-fluorouracil,and it had a good thermal stability.With 5-fluorouracil for the positive control group,the cytotoxicity tests in human renal embryonic cell HEK293 and the antitumor activity tests in hepatocellular carcinoma cell HepG-2 were carried out by the methyl thiazolyl tetrazolium method.The toxicity of the compound FNSW was lower than that of 5-fluorouracil,and compared with 5-fluorouracil the compound FNSW could inhibit HepG-2cell in vitro with significant difference.The rare earth clement Nd increased the biological activity of polyoxometalate significantly.     

Noble Metal Nanocrystal‐Incorporated Fullerene‐Like Polyoxometalate Based Microspheres

Monodisperse fullerene‐like polyoxometalate‐based microspheres are synthesized using a single‐phase approach which is quick, easier to control surfactant to polyoxometalate (POM) molar ratios and result in better control over the size‐distribution range. Noble‐metal nanocrystals are successfully incorporated in the surfactant encapsulated complex multilayered spherical assemblies without any change in their layered morphology. Combining the merits of fullerene‐like POMs and monodisperse noble metal nanocrystals, these monodisperse hybrid spheres show interesting composition‐ and size‐dependent photochemical properties.     

Organized Nanostructured Complexes of Polyoxometalates and Surfactants that Exhibit Photoluminescence and Electrochromism

A variety of functional nanostructured organic/inorganic hybrid materials from the europium‐exchanged derivative of a Preyssler‐type polyoxometalate (POM), [EuP₅W₃₀O₁₁₀]^12?, and functional organic surfactants were prepared by the ionic self‐assembly (ISA) route. The effect of organic surfactants on the structure, photoluminescent, electrochemical and electrochromic properties of the POM anions was investigated in detail. All obtained hybrid materials are amphotropic, i.e., exhibit both thermotropic and lyotropic liquid‐crystalline phase behaviour. Investigations of their photophysical properties have shown that the interactions of the various surfactants with the polyanions influence the coordination environments and site symmetry of Eu³⁺ in different ways. The functional groups in the organic surfactants significantly influence the electrochromic properties and photoluminescence of POMs. Different from normal and pyridine‐containing complexes, no photoluminescence and no electrochromism were observed from the ferrocene‐containing complexes. This may be explained in view of charge transfer between the POM anion and the ferrocenyl group.     

A Decade of Oxothiomolybdenum Wheels: Synthesis,Behavior in Solution,and Electrocatalytic Properties

The last decade has see the development of sulfur-containing polyoxometalates (POTMs) as a subclass of the polyoxometalate family. The structural and physico-chemical properties of this emerging class of compounds is dominating by the striking coordination properties of the [Mo₂O₂S₂(OH₂)₆]²⁺ oxothio cation, used as a building block. The cyclic topology of this arrangement corresponds to the main feature of the {Mo₂O₂S₂}-based compounds, able to develop cycle-based chemistry. The control of the linear oligomerization of the {Mo₂O₂S₂} core is achieved by the presence of the anionic component, which acts as a template. Here, we report on recent examples which illustrate how the use of various template ions such as halide, sulfate, polyphosphate, and polycarboxylate anions allows to tune the nuclearity of the inorganic host from {Mo₈} to {Mo₁₈}. A special focus on behavior in solution is given, highlighting the dynamic and fluxional character of these host–guest systems. The Diffusion Ordered Spectroscopy (DOSY) ¹H NMR, carried out on a large series of cycle-based and capsule-like compounds, demonstrates that such a method can be applied for the speciation of POM anions in solution. Finally, electrocatalytic behavior of the {Mo₂O₂S₂}-based compounds is presented. Preliminary results show that the electrocatalytic reduction of protons into hydrogen (HER) could constitute one of the most relevant applications for this class of molecular compounds.     

Counterion Interaction and Association in Metal-Oxide Cluster Macroanionic Solutions and the Consequent Self-Assembly

The interaction between large metal-oxide polyanions and their counterions is unique. Owing to their size disparity, there is a moderate ion-pairing effect and loose distribution of counterions around macroions, which leads to the unique solution behavior and the self-assembly of the macroions in polar solvents, and the counterion exchange capability around macroions. Furthermore, the macroion–counterion interaction also affects the catalytic behavior of the polyoxometalate (POM) clusters. Replacement of functionalized cations helps to modify the POM anions through static charge attraction. At the same time, the strong POM–counterion interaction can also lead to counterion-dependent synthesis. Recent developments on theoretical simulations help to understand this interaction at the molecular scale. This review summarizes the chronological progress of the exploration of macroion–counterion interaction (both theoretically and experimentally) and its impact on related research fields.     

含稀土多金属氧酸盐的杂化)自组装膜的制备和光学性质研究

用自组装方法构建含稀土多金属氧酸盐和聚丙烯胺的有机-无机杂化多层膜.用紫外可见光谱、原子力显微镜、X射线衍射等测试手段表征了膜的结构.计算了此杂化多层膜上分子的密度和独特的排列状态,以及分子在膜上逐层按比例的增长,用荧光光谱检测了自组装膜发光性能.指出在杂化自组装膜上,稀土的发光特性依然得到保持.