PVDF-Based Nanocomposite Solid Polymer Electrolytes; the Effect of Affinity Between PVDF and Filler on Ionic Conductivity

Nanocomposite solid polymer electrolytes (NSPEs) based on poly(vinylidene fluoride) (PVDF) were prepared by dispersing two kinds of organoclay (Cloisite^® 30B, Cloisite^® 15A) consisting of silicate layers in the polymer matrix. The effect of affinity between PVDF and organoclay as the filler on ionic conductivity was investigated in relation to its content, dispersed condition of organoclay, and structural changes of nanocomposites. The characterizations of PVDF-based nanocomposites with various organoclay contents were carried out by XRD, TEM, DSC, and DMA. In order to confirm the ion conduction properties of NSPEs with LiCF₃SO₃ at room temperature, ac impedance analyzer and FT-IR spectrometer were used. As a result, a higher ionic conductivity appeared in the case of NSPE with C15A than that with C30B and the maximum conductivity was 1.04 × 10^–3 S/cm for the NSPE containing 5 wt% of C15A and 40 wt% of LiCF₃SO₃.     

非水介质中全硅沸石分子筛合成的研究 全硅方钠石和全硅ZSM-39 的晶化

在乙醇胺及甘油和乙二胺混合物两种非水介质中合成了全硅方钠石。 在广泛的有机介质中进行了全硅沸石合成的研究, 首次获得了全硅ZSM-39及未知结构硅酸盐K相。 通过X射线衍射、红外光谱、组成分析、差热与热重分析等方法对合成的晶体产物进行了鉴定。 应用液相电导率-硅酸根离子浓度测量方法对非水溶液的性质及对非水介质中全硅沸石生成的必要条件进行了探讨。     

共轭高分子体系的分子轨道理伦V:二维重复单胞体系本征方程的因子分解方法

本文将一维重复单胞体系本征方程的因子分解方法向二维体系作了一般的推广,从而解决了一些重复单胞构成的二维大分子体系的能谱问题 , 利用因子分解法,本文研究了石墨二维平面分子边缘的化学反应活性以及体系的电子结构, 导电性与分子尺度的关系, 结果表明, 对于石墨类分子, 边界效应是非常显著的, 且体系的反应活性, 导电机制与边界的结构紧密相关。     

Na^+, K^+//Cl^-, SO4^2^-, CO3^2^——H2O五元体系25℃介稳相图的研究

用等温蒸发方法研究了NaCl饱和下的Na^+, K^+//Cl^-, SO4^2^-, CO3^2^--H2O五元体系25℃介稳相图, 测定了溶液的密度、粘度、折光率、电导率、PH和蒸汽压, 并由蒸汽压数据求得了水活度和渗透系数。在Janecke相图上有五个结晶区, 即Na2SO4,Na2CO3·2Na2SO3, Na2SO4·3K2SO4, Na2CO3·7H2O和KCl相区, 与Harvie和Weare计算相图比较, 无水芒硝和七水碳酸钠结晶区明显扩大, 碳钠矾相区明显缩小, 钾石盐和钾芒硝相区基本相近。用经验或半经验公式描述了溶液的密度、折光率和粘度随浓度的变化规律。用Pitzer电解质溶液模型计算了水活度和析出盐的溶度积。结果是令人满意的。     

海藻酸酮膜表面的配位结构及催化MMA聚合的性能

将海藻酸钠(SA)与CuCl2.2H2反应得到一种配位聚合物海藻酸酮(Cu-An)。以ESR、电导率、IR和SPS方法对此配位聚合物进行表征,确定了组成与结构：同时研究了甲基丙烯酸甲酯(MMA)在该配位聚合物膜、HSO3^-和水体系催化引发作用下的聚合反应历程。结果表明,配位聚合物的中心离子Cu^2^+与两个海藻酸(An)链节单元上的两个羧羟基氧原子和两个离解氢原子的羧羟基氧原子以共价型配位,配位数为4.MMA在上述的催化引发体系中是按照自由基加聚反应历程进行聚合的,PMMA呈无规结构。Cu-An在催化引发体系中起着催化剂的配位催化作用。     

Preparation and characterization of LiFePO4 /Ag composite for Li-ion batteries

Ag is introduced to the surface of LiFePO₄ prepared from liquid phase and heated at different temperatures. SEM, XRD and electrochemical characterization are used to compare the differences between LiFePO₄ and LiFePO₄/Ag. The results are discussed from the viewpoint of impedance of the cathode composite. With increase of the particle size, Ag shows stronger function as conductor in the composites.     

Melt mixing of polycarbonate/multi-wall carbon nanotube composites

—Composites of polycarbonate (PC) with multi-wall carbon nanotubes (MWNT) of different concentrations are prepared by diluting a PC based masterbatch containing 15 wt% MWNT using melt mixing in a DACA-Micro Compounder (4 g scale). Electrical resistivity measurements indicate that the percolation of MWNT is reached between 1 and 1.5 wt%. In addition, melt rheology was applied as another sensitive method to detect the percolation of the nanotubes. Atomic Force Microscopy and visual observations of the composite dispersions in a PC-solvent were used to characterise the state of MWNT dispersion. Differential Scanning Calorimetry and Dynamic Mechanical Analysis were applied to detect changes in the glass transition temperature of PC as a result of processing and of MWNT interactions with the PC matrix including the state of dispersion. In addition, DMA confirmed the reinforcement effect of the nanotubes. The results show that the nanotube incorporation also influences the processing behaviour. Due to the enhancement in melt viscosity by adding nanotubes and the enhanced shear forces, the molecular weight of the PC in the composites is reduced as compared to PC extruded under the same conditions. This effect leads to changes in the glass transition temperature and modulus which counteracts the effects originating from the nanotube-polymer interaction.     

Computer Simulation Study of Model Nafion Membrane in Water/Methanol Solvent

Using NPT and NVT molecular dynamics simulation techniques, we have simulated an atomistic model of solvated Nafion in the lithium salt form, with the following three main objectives: (i) to obtain details on the local environment of the lithium cations and to assess the solvent effect on their binding, (ii) to investigate the translational and rotational motion of solvent molecules (water and methanol) absorbed in the polymer matrix, and (iii) to elucidate details of the ionic transport though the hydrophilic regions of the membrane and to study the ionic conductivity as a function of solvent (water/methanol) composition. A property which is of central importance for understanding the functional features of Nafion materials, including direct methanol fuel cells, is the ionic conductivity and methanol crossover. We have found that conductivity parameter is strongly dependent on the solvent composition and determined by the solvation effects and the spatial distribution of polar sulfonate groups in ion-conductive channels.     

BaxCe0.8Y0.2O3-α固体氧化物燃料电池性能

用高温固相反应法合成了BaxCe0.8Y0.2O3-α（x=1.03,1,0.98)系列固体电解 质，用粉末X射线衍射法研究了样品的晶体结构，用氢及氧浓差电池方法研究了样 品的质子及氧离子导电特性，测定了它们的氢－空气燃料电池的放电性能。结果表 明，各样品均为钙钛矿斜方晶单相结构；质子导电和燃料电池输出电流密度均随样 品中钡离子含量的增加而增大，Ba1.03Ce0.8Y0.2O3-α具有最大的质子导电性和燃 料电池输出电流密度；各样品的氧离子导电性几乎不受钡离子含量影响。     

阴离子型微乳液的电导行为及其溶液结构

根据电导测量,研究了属于W/O→双连续→O/W一类微乳液的十二烷基硫酸钠(SDS)/正丁醇/辛烷/水体系的溶液结构.并探讨了表面活性剂离子对微乳液导电行为的贡献,以及表面活性剂与助表面活性剂含量、油含量对微乳液溶液结构的影响.微乳液的导电行为在W/O子区域中主要是由于SDS阴离子和在O/W子区域中是由于Na离子的影响.在双连续区(IZ)中SDS阴离子和Na阳离子都能影响导电行为增加表面活性剂含量有助于形成O/W微乳液,而助表面活性剂和油含量都增加有助于于形成W/O微乳液.