聚氨酯－高氯酸锂固态离子导体的低频交流特性分析

测定了聚氨酯－高氨酸及固态离子导体的交流阻抗谱，分析了离子导体的温度依赖性和低频介电特性．结果表明，聚氨酯－高氨酸锂固态离子导体具有较高的离子导电率，导电率的温度依赖性服从经验的ＶＴＦ方程，离子导体表现出非Ｄｅｂｙｅ型介电行为．     

磺酸型聚氨酯离聚物的离子导电性能

本文以多种聚醚为软段，二异氰酸酯（ＭＤＩ和ＴＤＩ）为硬段，合成了多嵌段聚醚聚氨酯，以此聚氨酯为基材，与ＮａＨ及１，３－丙碳酸内酯反应，进一步合成了一系列不同离子化程度的阴离子型碳化聚氨酯离聚物，用交流阻抗谱仪测定了样品的阻抗谱，由此计算出样品的离子电导率。研究结果表明其他条件相同时，以聚乙二醇（ＰＥＧ）为软段的样品具有较高的离子电导率；以聚环氧丙烷（ＰＰＯ）为软段的样品次之，以聚四氢呋喃（ＰＴＭＯ）为软段的样品最低，对于离子化程度不同的聚氨酯离聚物以金属离子和烷氧单元之比为０．０５时导电性能最好。阳离子为Ｌｉ＋和Ｎａ＋的样品具有相近的离子电导率。     

聚氨酯—高氯酸锂固态离子导体的低频交流特性分析

测定了聚氨酯－高氯酸锂固态离子导体的交流阻抗谱。分析了离子导体的温度依赖性和低频介电特性。结果表明，聚氨酯－高氯酸锂固态离子导体具有较高的离子导电率，导电率的温度依赖性服从经验的ＶＴＦ方程，离子导体表现出非Ｄｅｂｙｅ型介电行为。     

羧酸型聚乙二醇聚氨酯离聚物及其导电性能

以聚环氧乙烷（ＰＥＯ）为软段，与４，４’－二苯甲烷二异氰酸酯（ＭＤＩ）预聚，以２，２’－二羟甲基丙酸（ＤＭＰＡ）扩链合成了含羧酸基团的聚氨酯，并经中和形成了含不同金属离子的离聚物．测定了样品的热分析数据和力学性能，利用交流阻抗分析仪测定了样品的阻抗谱，由此计算出样品的离子电导率．这类样品由于阴离子（－ＣＯＯ－）固定在聚合物分子链上，因此只有单一阳离子迁移．结果表明，羧酸型聚氨酯离聚物既有较高的单一离子电导率又具有优良的力学性能．讨论了不同软段分子量、硬段含量和金属抗衡离子对离子电导性能的影响     

溶胶—凝胶法制备Na5YSi4O12及其离子导电性质

用溶胶－凝胶方法制备了钠快离子导体Ｎａ５ＹＳｉ４Ｏ１２（简称ＮＹＳ）的纯相，应用交流阻抗谱技术测定了样品的离子导电活化能，用扫描电子显微镜对用不同制备的样品烧结体表面进行了观察，与传统固相反应法制备的ＮＹＳ离子导体相比，用溶胶－凝胶方法制备的ＮＹＳ烧结体具有较好的界面效应。     

溶胶－凝胶法制备Na_5YSi_4O_（12）及其离子导电性质

用溶胶－凝胶方法制备了钠快离子导体Ｎａ_５ＹＳｉ_４Ｏ_（１２）（简称ＮＹＳ）的纯相，应用交流阻抗谱技术测定了样品的离子电导和离子导电活化能，用扫描电子显微镜对用不同方法制备的样品烧结体表面进行了观察。与传统固相反应法制备的ＮＹＳ离子导体相比，用溶胶－凝胶方法制备的ＮＹＳ烧结体具有较好的界面效应。     

La1-xSrxYO3-α陶瓷的合成及电性能研究

本文采用高温固相法合成了La1-xSrxYO3-α(x=0.00,0.05,0.10,0.15)系列陶瓷样品,用XRD、SEM对样品进行了表征,并用交流阻抗谱、氢泵、氢浓差电池、氧浓差电池等系统地研究了该系列样品的电性能.结果表明,该系列陶瓷样品均为钙钛矿型单斜晶相结构:样品的氢浓差电池电动势的实测值和理论值吻合得很好,表明样品在氢气气氛中为纯离子导体;氢泵测试结果证实了样品在氢气气氛中基本上是质子导体;氧分压与电导率的关系表明样品在高氧分压气氛中是离子(质子+氧离子)和空穴的混合导体.在低氧分压气氛中是离子(质子+氧离子)导体;氧浓差电池测试结果表明样品在干燥的氧化性气氛中是氧离子和空穴的混合导体.     

氧离子导体La_2Mo_(1.9)Sc_(0.1)O_9的合成及电性能研究

采用固相法首次合成了氧离子导体La2Mo1.9Sc0.1O9陶瓷样品,进行了XRD、SEM表征,用交流阻抗谱、氧浓差电池等电化学方法研究了样品在450～850℃下的离子导电性。结果表明,该陶瓷样品具有立方相La2Mo2O9结构,掺杂5%的Sc3+能有效地抑制La2Mo2O9在大约580℃时的相变;在氧化性气氛中是纯的氧离子导体,而在还原性气氛中为氧离子与电子的混合导体,850℃时的氧离子电导率为0.04S·cm-1。     

高分子阴离子电导的研究

制备了含Ｉ＾－榻解质薄膜,用阻抗谱法测量了样品的Ｉ＾－电导率,分析了样品的频响特性曲线,用Ｗａｇｎｅｒ直流极化法测量了样品的电子电导。实验发现,此阴离子导体几乎和相应的含Ｎａ＾＋有相同的离子电导率,且随着碘含量的增加, 率增大。离子电导实验结果表明,在此阴离子导体中,电子电导占总电导率的９％,而空穴的导导率比电子电导率小１￣２个数量级。     

PEO与Li1.3Al0.3Ti1.7(PO4)3络合的离子导体聚合物电解质

将实验室经固相反应的精细Li1．3Al0．3Ti1．7(PO4)3盐与聚氧化乙烯(PEO)按照不同，nEO／nLi摩尔比，通过溶液浇铸法制备了固态聚合物电解质。红外光谱分析表明Li1．3Al0．3Ti1．7(PO4)3盐与PEO之间有络合产生。SEM照片显示PEO晶体外层为无定形相所包覆形成的胞状结构。经电化学阻抗(简称EIS)法测试发现聚合物电解质膜的室温阻抗谱图是由高频处一压缩的半圆和低频下一条直线组成，而高温时的阻抗谱主要为一条直线。离子电导率的测试结果得到：当nEO／nLi=16时，聚合物电解质室温下电导率约为10^-6／cm，343K时达到10^-4s／cm。离子迁移率的数据表明聚合物电解质为离子和电子共混的导体，但在聚合物电解质体系中电荷的迁移主要是由离子作为载流子导电造成的，由测试结果可得此电解质为离子导体。     

复合聚合物电解质的导电行为及电导率的测定

研究了乙烯碳酸酯（EX）增塑的（PEO）16LiClO4-EC复合聚合物电解质交流阻抗谱图，提出了不锈钢电极／聚合物电解质／不锈钢电极这种结构在交流阻抗测试分析中具有普适性的模拟等效电路，并且根据等效电路中元件拟合值测定出复合聚合物电解质体系在不同EC增塑量及温度时的电导率，用复合聚合物电解质体系中各组分之间的相互作用解释了EC对聚合物电解质电行为的影响，在低EC含量的复合聚合物电解质体系中，电导率和温度的关系在低温时符合Arrhenius方程，在高温时符合Vogel-Tamman-Fulcher(VTF)方程；而当EC含量大于20％时，电导率和温度的关系在实验温度范围内符合VTF方程。     

Impedance modelling of two-phase solid-state ionic conductors. Part I—theoretical model and computer simulations

An equivalent circuit model is introduced to account for the impedance properties of solid state ionic conductors, composed of two distinct phases. The model is developed on the basis of physical arguments, regarding the micrometer-scale structure of the two-phase material system and the comparison of different possible equivalent circuit representations. The final equivalent circuit reduces to two simpler circuits, suitable for fitting experimental impedance spectra. Computer simulations are provided to demonstrate the non-Arrhenius behaviour, which is observed in the temperature dependence of the ohmic elements of the equivalent circuits used for data analysis. This complex dual-slope behaviour of the Arrhenius plot is in agreement with the predictions of the model. Finally, with the aid of mathematical calculations and illustrated by computer simulations, a modified Arrhenius plot evaluation procedure was developed to derive correctly the electrical properties of the individual constituent phases from impedance measurements.     

Impedance spectroscopy of the electrode-tissue interface of living heart with isoösmotic conductivity perturbation

Impedance spectroscopy was used to solve the Pt electrode interface with metabolically active perfused living heart. Three impedance spectra were observed: the Warburg impedance (Z_W∞), a single high angle constant-phase-element, and a thin-film impedance (Z_D). When characterized again after cyclic change of ionic strength (and hence conductivity κ) each interface had one of only two spectra, with exclusion of Z_W∞. The in vivo interfacial impedance spectrum is thus neither single-valued nor stable in time. Because metal|living tissue interfaces are obligatory circuit elements in biosensors and electrodes in heart and brain, the multiple-valued and thin-film character of its impedance are significant.     

Impedance modelling of two-phase solid-state ionic conductors. Part II—application to high-lithium-content <Emphasis Type="Italic">x</Emphasis>Li<Subscript>2</Subscript>O–B<Subscript>2</Subscript>O<Subscript>3</Subscript> fast-ion conducting glasses

The equivalent circuit model of two-phase ionic conductors, introduced in Part I of this work, was applied to a set of xLi₂O–B₂O₃ fast-ion conducting glasses, with x ranging from 3.0 to 4.5. The shape of Arrhenius plots, constructed by equivalent circuit fitting of impedance spectra measured at various temperatures, turned out to be in agreement with the predictions of the model. The analysis procedure, which was developed by mathematical investigation in accordance with the implications of the model, was employed to determine the activation energies of the two present phases and the total DC ionic resistivity of the examined glasses.     

Impedance spectra analysis of thermoresponsive poly(acryloyl‐L‐proline methyl ester) gel membrane in LiCl solution

Impedance spectra analysis of a thermoresponsive poly(acryloyl‐L ‐proline methyl ester) (poly(A‐ProOMe)) hydrogel membranes in an aqueous solution of LiCl was carried out using a simple equivalent model. The hydrogel membrane was synthesized by γ‐radiation‐induced polymerization and crosslinking of A‐ProOMe monomer aqueous solution in a glass‐cast. By means of the impedance spectra analysis, a novel method for the calculation of the ionic conductivity of the hydrogel membranes in LiCl solution was proposed. The calculated ionic conductivity was in agreement with the determined value. In addition, effects of temperature and LiCl concentration on the impedance spectra and ionic conductivity of the gel membrane were analyzed. Results indicated that the impedance spectra analysis is a very useful tool for evaluating the electric properties of gel membranes in an electrolyte solution. The poly (A‐ProOMe) gel membrane in 1.0 M LiCl solution showed a high ionic conductivity of about 0.2 S/cm at 14 °C. The temperature‐dependence of the ionic conductivity was a complex nonlinear form due to the volume phase transition of the thermoresponsive poly(A‐ProOMe) gel membrane, and the volume phase transition temperature appeared to be decreased with the increase in the LiCl concentration. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2843–2851, 2005     

Syntheses and characterizations of soft‐segment ionic polyurethanes

Novel soft‐segment ionic polyurethane (linear and crosslinking) have been prepared based up on sodium sulfonate–side chains poly(ethylene oxide) (SPEO). SPEO was synthesized by grafting the sodium sulfonate onto the chain of poly(ethylene oxide) with molecular weights of 400, 600, 800, and 1000. The SPEO and the ionic polyurethane were characterized by elemental analysis, ¹H‐NMR, ¹³C‐NMR, gel permeation chromatography, and impedance analysis. The effect of plasticizer on the ionic conductivity of the polyurethane was also investigated. These solid polymer electrolytes possess a higher ionic conductivity (about 10⁻⁶ S/cm at room temperature) than the corresponding sulfonated hard‐segment polyurethane electrolytes. The presence of the hydroxyl group in the electrolyte tends to lower the ionic conductivity. Crosslinking of polyurethane results in the enhancement of the dimensional stability, while maintaining the same level of the ionic conductivity. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 837–845, 1999     

Methods to study the ionic conductivity of polymeric electrolytes using a.c. impedance spectroscopy

Composite polymeric electrolytes of PEO-LiClO₄-Al₂O₃ and PEO-LiClO₄-EC were prepared and the ionic conductivity by a.c. impedance was calculated using four different methods, and three kinds of representations of a.c. impedance spectra were adopted. The first is based on the Nyquist impedance plot of the imaginary part (Z″) versus the real part (Z′) of the complex impedance. The second and the third correspond to the plots of imaginary impedance Z″ as a function of frequency (f), and the absolute value (|Z|) and phase angle (θ) as a function of f, respectively. It was found that the values of the ionic conductivity calculated using the three representations of a.c. impedance spectra are basically identical. Electronic Publication     

Electrical impedance spectroscopy study of piezoelectric PVDF membranes

Piezoelectric poly (vinylidene fluoride) (PVDF) membranes were prepared from pre-fabricated membranes by electrically poling in an intense electric field. The electrical impedance of PVDF membranes measured over a frequency range of 10^?2–10⁵ Hz before and after poling is presented. The effect of pressure on the impedance characteristics of un-poled and poled PVDF membranes was also studied. A four element model circuit, including a constant phase element (CPE) was fitted to the impedance spectra. The elements of the circuit fitted to the poled sample were more conductive compared with those of the un-poled sample. Stronger CPE elements in the circuit were detected in the poled samples under pressure suggesting that the piezoelectric activity of PVDF is the major contributor to the constant phase angle seen at low frequencies.     

碱土金属双掺杂的Ce_(0.9)Ca_(0.1-x)Sr_xO_(1.9)中温固体电解质的性能与应用

以固相反应方法合成了碱土 (Ca ,Sr)双掺杂的氧化铈基固溶体材料Ce0 .9Ca0 .1 -xSrxO1 .9(x =0 ,0 0 4,0 0 5 ,0 0 6 ,0 1)。结构研究表明 :碱土双掺杂的CeO2 呈立方萤石结构。利用阻抗谱研究了材料的离子导电性 ,发现碱土双掺杂有利于提高材料离子导电率 ,掺杂两种碱土金属离子的等效半径接近临界离子半径时导电率最高。将此系列材料作为电解质进行了燃料电池试验 ,发现电池的输出功率高于YSZ电解质及碱土单掺杂氧化铈 ,且电池输出开路电压亦高于单掺杂的情况。