Ionic liquid crystal-based electrolyte with enhanced charge transport for dye-sensitized solar cells

A room temperature ionic liquid crystal,1-dodecyl-3-ethylimidazolium iodide(C12EImI),and an ionic liquid,1-decyl-3-ethylimidazolium iodide(C10EImI),have been synthesized,characterized and employed as the electrolyte for dye-sensitized solar cells(DSSC).The physicochemical properties show that a smectic A(SmA)phase with a lamellar structure is formed in C12EImI.Both C12EImI and C10EImI have good electrochemical and thermal stability facilitating their use in DSSC.The steady-state voltammograms reveal that the diffusion coefficient of I3–in C12EImI is larger than that in C10EImI,which is attributed to the existence of the SmA phase in C12EImI.Because the iodide species are located between the layers of imidazolium cations in C12EImI,exchange reaction-based diffusion is increased with a consequent increase in,the overall diffusion.The electrochemical impedance spectrum reveals that charge recombination at the dyed TiO2/electrolyte interface of a C12EImI-based DSSC is reduced due to the increase in I3–diffusion,resulting in higher open-circuit voltage.Moreover,both short-circuit current density and fill factor of the C12EImI based DSSC increase,as a result of the increasing transport of I3–in C12EImI.Consequently,the photoelectric conversion efficiency of C12EImI-based DSSC is higher than that of the C10EImI–based DSSC.

Mesomorphous structure change by tail chain number in ionic liquid crystalline complexes of linear polymer and amphiphiles

Three polymer-amphiphile complexes were prepared by combining poly（allylamine hydrochloride）（PAH） with the potassium salt of mono-,di-,and trisubstituted benzoic acid dendrons（4-octyloxybenzoic acid,3,5-dioctyloxybenzoic acid,and 3,4,5- trioctyloxybenzoic acid）.The solid structure and properties were monitored with FT-IR,XRD,TG,DSC,and polarized optical microscope（POM）.Difference in the tail chain number of the dendritic amphiphile induced two different mesomorphous structures： lamella for the mono-,disubstituted dendron containing complexes and hexagonal column for the trisubstituted dendron containing complexes.These corresponded to the ionic thermotropic liquid crystal SmA andΦ_h phases,respectively.This finding is significant for design of functional nanostructures based on the ionic complexation of polymers and amphiphiles.

Solvent-free Synthesis,Crystal Structure and Thermal Stability of Ionic Liquid 1-Hexadecyl-3-methylimidazolium Bromide

Ionic liquid 1-hexadecyl-3-methylimidazolium bromide [C16mim]Br was synthesized by solvent-free alkylation of N-methylimidzole with hexadecyl bromide. A large transparent single crystal of 1-hexadecyl-3-methylimidazolium bromide monohydrate （[C16mim]Br·H2O）, 4 mm in length, was firstly obtained in the water-trichloromethane-toluene growth system （Vwater＇Vtrichloromethane＇Vtoluene = 0.1：1：2）. The crystal structure was determined by single-crystal X-ray diffraction method. It crystallizes in the triclinic system, space group P1, with a = 5.4962（15）, b = 7.839（2）, c = 27.279（8） A, α = 94.375, β = 91.500, γ = 101.999°, Z = 2, V = 1145.2（5） A3, C20H41BrN2O, Mr = 405.46, Dc = 1.176 Mg/m3, μ = 1.804 mm^-1, F（000） = 436, the final R = 0.0523 and wR = 0.1345. The 3D supramolecular structure is constructed through weak interactions between imidazolium cations, Br- anions and lattice water molecules. The long alkyl chain to the imidazolium ring and lattice water molecules play an important role in the self-assembly process. Moreover, it is proposed that [C16mim]Br in water has aggregation behavior and the possible self-assembled structure is the interdigitated pattern. Finally, thermal stability of [C16mim][Br]·H2O was also studied by DSC and TGA analysis.

The Effect of Ionic Liquids on the CaCO_3 Crystal Growth

In this paper, the effect of ionic liquids on the CaCO3 crystal growth has been studied for the first time. The obtained CaCO3 crystals were charactered by the X-ray diffraction and scanning electron micrographs. The results showed that the control ability of ionic liquids for CaCO3 crystals growth was dependent on the counter anion very much.

Aminopropyl-containing ionic liquid based organosilica as a novel and efficient adsorbent for removal of crystal violet from wastewaters

Herein a novel aminopropyl-containing ionic liquid based organosilica(ILOS-NH_2) is prepared, characterized and applied as effective adsorbent for removal of crystal violet(CV) dye from wastewater. The ILOS-NH2 material was synthesized by hydrolysis and co-condensation of 1,3-bis-(3-trimethoxysilylpropyl)-imidazolium chloride(BTMSPIC) under acidic conditions followed by treatment with 3-aminopropyl-trimethoxysilane in toluene under reflux conditions. This material was characterized using scanning electron microscopy(SEM), diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS), thermal gravimetric analysis(TGA) and energy dispersive X-ray analysis(EDAX). The material was effectively used in the removal of crystal violet at ambient temperature and showed high capacity and stability under applied conditions. The efficacy of p H, contact time, adsorbent dose, initial dye concentration, temperature, and isotherm studies and the applicability of pseudo-first, second order and Elovich kinetic models have also been investigated.

Oscillating Frequency Response of a Langasite Crystal Microbalance in Liquid Phase

The frequency responses of a langasite crystal microbalance （LCM） in liquid phase were investigated. It was shown that the LCM possessed much stronger oscillating ability in liquid phase than that of the commonly used quartz crystal microbalance （QCM）. The frequency shifts of the LCM to the changes in mass loading, as well as viscosity and density of the liquid were measured. The LCM was applied to monitor the adsorption process of an ionic liquid film to ethanol vapor.

Correlation between Structure and Thermal Properties of N-vinyl-3-alkylimidazolium Magnetic Ionic Liquids

Influence of structural variations of N-vinylimidazolium tetrahalogenidoferrate(III) magnetic ionic liquids(MILs) on thermal properties was investigated. Using Gaussian09/B3 PW91/6-311 G(2d, p) density functional methods, the microstructure of the MILs were analyzed. With differential scanning calorimeter(DSC) and thermogravimetric analysis(TGA), the thermal properties of the MILs were performed. The results showed that the interaction energies of ion pairs decreased, the crystallization temperature increased first and then decreased, and the surfusion first decreased and then increased with the elongation of the alkyl chain length on cation;with the increase of Br atom, the interaction energies of ion pairs increased;the interaction energies of ion pairs increased in the MILs with the same cation or anion, the nature of polarity of MILs increased and the melting point rose;as the cation or anion in MILs had a smaller size, it could have the solidsolid transition temperature. The results indicated that the decomposition temperature with the same type of MILs increased with the interaction energies of ion pairs. The interaction energy of ion pairs can be used to illuminate the correlation between the thermal properties and the structure of MILs. ILs possesses the properties of macromolecular.

液晶电解质在锂离子电池中的研究进展

液晶电解质作为新型电解质材料,具有高离子导电性、优异的力学性能和热稳定性等优点,成为近年来锂离子电池领域研究的热点之一。液晶电解质可以通过自组装形成柱状相、近晶相或双连续立方相等结构,为锂离子的传输提供高效的离子传输通道。综述了液晶电解质在锂离子电池中的应用及研究进展,主要包括液晶电解质的基本概念和在锂离子电池中的研究进展,主要从离子电导率、电化学稳定性和充放电循环这3个方面来叙述。最后,对液晶电解质在锂离子电池领域未来的发展进行了展望。

Crystal structure and thermal decomposition kinetics of1-(pyridinium-1-yl)propane-(1-methylpiperidinium)bi[bis(trifluoromethanesulfonyl)imide], [PyC_3Pi][NTf_2]_2

The structure of a room temperature asymmetrical dicationic ionic liquid(ADIL), 1-(pyridinium-1-yl) propane-(1-methylpiperidinium) bi[bis(trifluoromethanesulfonyl)imide]([PyC 3Pi][NTf2]2), was studied by the X-ray diffraction method. Meanwhile, thermal analysis of [Py C3Pi][NTf2]2was also studied using non-isothermal thermogravimetric analysis(TGA). The title crystal belongs to the triclinic with space group Pī and unit-cell parameters a = 0.95217(8) nm, b = 1.05129(11) nm, c = 1.70523(14) nm, α = 89.759(8)°, β = 80.657(7)°, γ = 68.007(9)°, and F(000) = 792. Thermal stability and thermal decomposition kinetics of the title compound were also investigated using TGA under the atmosphere of highly pure nitrogen. Heating curves at different rates were correlated with kinetic equations Friedman and ASTM(also called iso-conversion method). The values of average activation E(k J·mol-1) and pre-exponential constant lg A are 149.58 k J·mol-1and 8.83, respectively, which were obtained by the two methods. The kinetic model function, activation energy and pre-exponential constant of this reaction using the multivariate non-linear-regression method were f(α) =(1- α)(1 + 4.1870α), 151.04 k J·mol-1and 8.81, respectively, which were basically consistent with iso-conversion methods.

Synthesis and Crystal Structure of 2-(1-Naphthalenylamino)-4-thiazolidinone

The compound 2-（1-naphthalenylamino）-4-thiazolidinone was synthesized by the reaction of 1-（naphthalene-1-yl）thiourea with ethyl chloroacetate in an ionic liquid, and its structure was characterized by IR, 1H NMR and single-crystal X-ray diffraction. The crystal of the title compound belongs to monoclinic, space group P21 /c with a=10.0081（3）, b=14.5312（4）, c=7.8739（2） , β=99.425（3）°, Z=4, V=1129.64（5）3 , Dc=1.425 g/cm3 , μ=0.269 mm-1 , F（000）=504, the final R=0.0519 and wR=0.1507. X-ray analysis indicated that the five-membered ring is essentially planar in this molecule, and intermolecular hydrogen bonds N（1）-H（1）…N（2）, C（3）-H（3）…O（1）, C（4）-H（4）…O（1） and C（12）-H（12a）…O（1） were observed. π-π Stacking interactions contribute to the stability of the structure. DSC-TG analysis showed that the title compound experienced a phase change at 190 ℃ and began to decompose above 240 ℃.

离子液体对溶菌酶晶体形态和活性的影响

以鸡蛋清溶菌酶为模型蛋白,采用冷却结晶法结晶以及浊度法测定酶活性,研究了分别添加4种亲水性离子液体(1-丁基-3-甲基咪唑四氟硼酸盐([C_(4)mim]BF_(4))、1-丁基-3-甲基咪唑氯盐([C_(4)mim]Cl)、1-丁基-3-甲基咪唑溴盐([C_(4)mim]Br)和1,3-二甲基咪唑碘化物([dmim]I))条件下溶菌酶晶体形态和晶体活性的变化。利用光学显微镜对溶菌酶结晶过程的晶体形态进行分析,结果表明添加离子液体会影响溶菌酶的晶体形态和尺寸。离子液体[C_(4)mim]BF_(4)介导的溶菌酶形成棒状晶体。与未添加离子液体相比,[C_(4)mim]Cl和[C_(4)mim]Br均未改变溶菌酶晶体形态,均呈块状晶体,但[C_(4)mim]Cl和[C_(4)mim]Br促进溶菌酶晶体生长,晶体尺度均增加。而添加[dmim]I,溶菌酶呈现针状晶体。采用浊度法测定溶菌酶晶体活性,结果表明不同的离子液体对溶菌酶晶体的活性影响不同。其中,[C_(4)mim]BF_(4)和[dmim]I的添加降低了溶菌酶晶体的活性,而[C_(4)mim]Cl和[C_(4)mim]Br的添加则提高了酶晶体的活性。

含偶氮苯基团咪唑离子液晶的合成及其光响应性

设计合成一种新型含偶氮苯基团的咪唑离子液晶化合物,并用核磁共振氢谱、质谱和红外光谱表征其结构,通过热重和差示扫描量热仪对其热性质进行表征.结果表明:该化合物在190℃前稳定存在,熔点为142.96℃,降温时在124.37~134.04℃出现液晶区间;用偏光显微镜可观察到化合物的球形织构,通过X射线衍射测试确认其为层状结构;在紫外光照射时,化合物从反式到顺式异构化的光响应时间为205 s,在日光灯照射时,化合物从顺式到反式异构化的光响应时间为595 s,反-顺异构化程度达80.4%.

离子液体对PA6结晶行为与宏观性能的影响

研究了不同浓度离子液体1-丁基-3-甲基咪唑四氟硼酸盐([BMIM]BF 4)对尼龙6(PA6)基膜宏观力学性能、结晶行为以及热稳定性的影响。实验结果表明,加入少量[BMIM]BF 4离子液体可以明显降低PA6的屈服强度和模量,红外光谱结果显示表明,[BMIM]BF 4中咪唑环上的氢原子与PA6分子中的酰胺基上的氮原子与氧原子形成氢键而削弱PA6分子链的氢键作用。随着[BMIM]BF 4用量的提高,PA6的熔融温度、结晶温度以及热稳定均有所下降,并且PA6样品晶粒尺寸明显减小,结晶更加困难。

高电压锂金属二次电池用离子型局部高浓电解液

基于有机离子盐(离子液体或离子塑性晶体)的离子型局部高浓电解液(iLHCEs)可用于高性能锂金属二次电池,但Li+传导能力、与锂金属负极和高电压正极的兼容性等需优化。使用有机离子塑性晶体N-乙基-N-甲基吡咯烷鎓双(三氟甲基磺酰)亚胺盐(Pyr12TFSI)构筑iLHCEs,形成的[Li^(+)][FSI-][TFSI-][Pyr12^(+)]紧密离子簇可衍生稳定的固体电解质相界面(SEI),抑制副反应发生与锂枝晶生成,使锂沉积/剥离的库仑效率高达99.03%。使用基于Pyr12TFSI的iLHCEs的高电压Li|LiCoO_(2)(4.5 V)及Li|LiNi_(0.5)Mn_(1.5)O_(4)(5.0 V)电池,具有较高的首次库仑效率、长循环稳定性及理想的倍率性能。

联苯类液晶改性纤维素膜的制备及其抗紫外性能

以1,6-二溴己烷、氰基联苯酚和N-甲基咪唑为主要原料,合成含有咪唑基团的联苯类液晶(CbP)。以离子液体1-烯丙基-3-甲基咪唑氯盐(AMIM·Cl)为溶剂,将木浆纤维素(WPC)与CbP共混得到铸膜液,再通过浸渍沉淀相转化技术将铸膜液制成纤维素液晶膜(WPC/CbP)。采用哈克流变仪对溶液性能进行表征,用傅里叶红外光谱(FT-IR)、X-射线光电子能谱(XPS)、差示扫描量热(DSC)等对膜结构和性能进行表征。结果表明,CbP的引入改变了纤维素分子内及分子间的氢键作用,提高了纤维素膜的热稳定性。当CbP在铸膜液中的质量分数为3%时,溶液黏度最低。与纯纤维素膜相比,此WPC/CbP膜的拉伸强度提高了27.56%,紫外光透光率降低了35%左右。

离子液脱硫工艺在铜冶炼烟气脱硫中的应用实践

介绍了离子液脱硫工艺在铜陵有色金属集团股份有限公司金冠铜业分公司奥炉厂区环集烟气和制酸尾气脱硫系统的应用实践情况。结合生产实践经验,重点介绍了尾气脱硫系统的过程控制与操作要点,贫/富液换热器和再沸器堵塞、再生SO2气体的处理受制酸系统制约、再生塔壳体和离子液输送管道腐蚀等常见故障及采取的处理措施。通过在环集烟气条件控制与离子液脱硫系统运行两方面不断持续优化,该离子液尾气脱硫系统投运5年来,运行稳定,脱硫效果较好,且不产生废渣,废水量少,再生的SO2气体可用于制酸,具有明显的环保优势,适用于蒸汽有富余的冶炼企业。

Crystal Structures, Thermal Analysis and Electrochemical Behaviors of Functionalized Pyridinium Ionic Liquids Comprising One 1-Ethyl Acetate Group

Pyridinium ionic liquids（ILs, 1-ethyl acetate pyridinium hexfluorophosphate [EAPy][PF6] and 1-ethyl acetate-3-methyl pyridinium hexfluorophosphate [EAMPy][PF6]）, were synthesized by a two-step process involving introduction of one ethyl acetate group and anion metathesis. Colorless single crystals of the two ILs were initially obtained using the solvent-evaporation method in mixed solvents. Single-crystal X-ray diffraction was used to deter- mine the crystal structures. [EAPy][PF6] crystallizes in the monoclinic space group C2/c with a-2.2748（16） nm, b=0.6204（4） nm, c=1.8552（12） nm and Z-8, whereas [EAMPy][PF6] crystallizes in the orthorhombic space group P212121 with a=0.7126（17） nm, b=1.2792（3） nm, c=1.5327（3） nm and Z-4. The structure of [EAPy][PF6] contains double zigzag chains formed by alternately pairing large organic cations with the octahedral anions of [P1F6]- or [P2F6] . The [P1F6] and [P2F6]- anions occupy respectively two distinct crystallographic sites in crystal packing models. The structure of [EAMPy][PF6] includes ladder-type chains constructed through pairing pyridinium cations with inorganic anions of [PF6]-. The [PF6]- anion in [EAMPy][PF6] shows a distorted octahedron structure and is sandwiched by ethyl acetate groups in crystallographic stacking. This study reveals the influence of chemical modification involving the methyl group（CH3） onto crystallographic structure of pyridinium ILs. Thermal analysis indicates that the difficult crystallization of the two 1Ls is related to the low void filling of ion pairs in crystal structure, leading to relatively low melting point and evident supercooling during the cooling process. Additionally, the experimental results indicate that the two ILs have electrochemical activity. The ethyl acetate group also allows downward shifting of electrochemical windows to less negative positions and the ionic conductivities of the two ILs follow an Arrhenius-type behavior.

基于POM,SAXS和Raman研究降温速率对[C_(12)mim][BF_(4)]熔体结晶过程及产物的影响

当前,高昂的生产和使用成本限制了离子液体规模化应用,如何回收再利用离子液体受到极大关注。离子液体结晶过程对研发新型回收技术至关重要,而降温速率对结晶过程有重要影响。基于此,以1-十二烷基-3-甲基咪唑四氟硼酸盐([C_(12)mim][BF_(4)])为研究对象,在60~0℃范围内对其进行快速(30℃·min^(-1))和慢速(1℃·min^(-1))降温,采用偏光(POM)、小角X射线散射(SAXS)和拉曼(Raman)等技术研究了该离子液体在降温过程中的相态转变和结构变化,揭示了降温速率对其熔体结晶过程及产物影响规律。POM研究表明:在快速降温过程中,[C_(12)mim][BF_(4)]经历了“液态-液晶态-晶态Ⅰ”转变,得到了晶粒数量少但尺寸较大的“球状”晶体;在慢速降温过程中,[C_(12)mim][BF_(4)]经历了“液态-液晶态-晶态Ⅱ”转变,得到了晶粒数量多但尺寸较小的“针状”晶体。SAXS研究表明:[C_(12)mim][BF_(4)]存在两种晶体结构,分别为“正交双层相”和“三斜双层相”,且同时出现在“晶态Ⅰ”中,而在“晶态Ⅱ”中只有“三斜双层相”一种晶体结构。由此可知,“晶态Ⅰ”是混合相晶体,而“晶态Ⅱ”是单一相晶体。此外,由Raman结果可知:“正交双层相”和“三斜双层相”中[C_(12)mim]^(+)构象存在较大差异,分别为“G构象”和“A构象”。综上所述,快速降温时,[C_(12)mim][BF_(4)]经历了“液态-液晶态-晶态Ⅰ”转变过程,得到了由“正交双层相”和“三斜双层相”组成的混合相晶体,该晶体同时含有[C_(12)mim]^(+)的“G构象”和“A构象”。慢速降温时,[C_(12)mim][BF_(4)]经历了“液态-液晶态-晶态Ⅱ”转变过程,得到了由“三斜双层相”组成的单一相晶体,该晶体只含有[C_(12)mim]^(+)的“A构象”。因此,降温速率对[C_(12)mim][BF_(4)]熔体结晶过程及产物具有重要影响。该研究结果为[C_(12)mim][BF_(4)]回收技术开发提供了重要实验数据,同时对研究其他同类型离子液体的相态转变和结构变化具有指导意义。

Enhanced Crystallization Kinetics of PLLA by Ethoxycarbonyl Ionic Liquid Modified Graphene

To investigate the performance of graphene(Gra) modified with ethoxycarbonyl ionic liquid(IL), chain mobility and crystallization kinetics of poly(L-lactic acid)(PLLA), a series of PLLA nanocomposites have been prepared using solution-cast method.IL can improve the dispersion of Gra in PLLA matrix and the samples containing IL have higher growth rate of PLLA spherulite than neat PLLA does. PLLA/IL/Gra and PLLA/2 Gra exhibit the same relaxation strength and time of αN relaxation that corresponds to the longest normal mode motion at 110-140 °C. PLLA/IL/Gra shows a faster crystallization rate than PLLA/2 Gra does, which might be attributed to the Gra-imidazolium cation interaction in IL modified Gra, the significant dispersion effect of IL at Gra surface, and the increase of nuclei density of PLLA/IL/Gra.

Hydrothermal Syntheses of CuO, CuO/Cu2O, Cu2O, Cu2O/Cu and Cu Microcrystals Using Ionic Liquids

In this paper, CuO, CuO/Cu2O, Cu2O, Cu2O/Cu and Cu microcrystals were synthesized via a hydrothermal method by mixing Cu（NO3）2·3H2O and NaOH together in the presence of an ionic liquid l-butyl-3-methylimidazolium tetrafluoroborate（[BMIM]BF4） or 1-butyl-3-methylimidazolium chloride（[BMIM]Cl）. The structures and the morphologies of the obtained products were characterized by means of X-ray diffractometer（XRD）, field-emission scanning electron microscopy/energy-dispersive spectroscopy（FESEM/EDS）, transmission electron microscopy/selected area electron diffraction（TEM/SAED） and Raman spectroscopy. The result of XRD indicates that Cu2O and Cu microcrystals are cubic phase and the Raman spectra confirm the presence of carbon. The results of FESEM and TEM images show Cu2O microcrystals as rule cubes of 2μm in length and Cu particles of 5 μm in diameter. According to the difference between crystal structures, bi-eomponent and single component products were synthesized by adjusting the reaction conditions. A possible formation mechanism of Cu2O and Cu was proposed in [BMIM]BF4.