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。     

固体电解质Li4.4M0.4Si0.6O4-xLi2O(M=Al,B)的低温合成及导电性

用溶胶－凝胶法,于７００℃合成了Ｌｉ４．４Ｍ０．４Ｓｉ０．６Ｏ４－ｘＬｉ２Ｏ（Ｍ＝Ａｌ,Ｂ;ｘ＝０．００－０．５０）离子导体材料,并用ＤＴＡ－ＴＧ、ＸＲＤ、ＳＥＭ及交流阻抗等技术对样品进行了测试,结果发现：用溶胶－凝胶法可降低Ｌｉ４．４Ｍ０．４Ｓｉ０．６Ｏ４的合成温度,随Ａｌ,Ｂ的掺杂,可提高基质材料的离子导电性,同时随Ｌｉ２Ｏ的掺入可增强样品的致密性并提高了其离子的导电性能。     

荧光素掺杂的TiO2凝胶的制备及光谱研究

近些年来,溶胶－凝胶（Ｓｏｌ－Ｇｅｌ）方法作为一种软化学合成方法具有很多优点［１］,例如制作简单、烧结温度低,制得样品稳定、坚韧,制备灵活性高等。作为一种常用的染料,荧光素（ＦＬ）常用于研究非线性光学。利用Ｓｏｌ－Ｇｅｌ法可以很好地将染料分子固定在光...     

NiO/γ-Al2O3催化剂中NiO与γ-Al2O3间的相互作用

利用溶胶－凝胶法制备了不同含量的 ＮｉＯ／γ－Ａｌ_２Ｏ_３催化剂,通过ＸＲＤ,ＸＰＳ和 ＴＰＲ等技术考察了制备方法、ＮｉＯ含量和焙烧温度对催化剂结构和Ｎｉ存在状态的影响,发现溶胶－凝胶法制备的催化剂活性组分ＮｉＯ与担体γ－Ａｌ_２Ｏ_３间具有强相互作用．详细地讨论了Ｎｉ物种的还原状态与以“Ｎｉ~０”为活性中心的催化反应的活性之间的关系．溶胶－凝胶法制备的催化剂经高温焙烧后,Ｎｉ以一种类尖晶石结构的固溶体形式存在,这种固溶体态尖晶石可能会抑制Ｎｉ的烧结和流失,提高催化剂的稳定性．     

醋酸和丙三醇对制备SrTiO3的影响

醋酸和丙三醇对制备ＳｒＴｉＯ_３的影响颜秀茹，霍明亮，王建萍，王菲，曾淑兰（天津大学化学系天津３０００７２）关键词　冰醋酸，溶胶－凝胶过程，丙三醇，ＳｒＴｉＯ_３ＳｒＴｉＯ３是电子材料中使用最广的材料之一，有关它的制备已有不少报道。一般可以通过ＳｒＣＯ...     

溶液－溶胶－凝胶（SSG）法制备高均匀性Bi系超导体原始粉末的SSG转变判据

溶液－溶胶－凝胶（ＳＳＧ）法制备高均匀性Ｂｉ系超导体原始粉末的ＳＳＧ转变判据毛传斌，周廉，杜泽华，吴晓祖（西北有色金属研究院超导材料研究所，宝鸡７２１０１４）１引言溶胶－凝胶法是指金属有机或无机化合物经过溶液、溶胶、凝胶而固化，再经热处理而成氧化物或...     

含时间变量的凝胶溶胶分配方程及其应用

在Ａａ－Ｂｂ型综聚反应的凝胶溶胶分配（ＧＳＤ）方程中引入相应的聚合反应动力学方程．模拟计算的溶胶分数（Ｓ）对反应程度（Ｐ_Ｂ，Ｐ_Ｂ＇）的关系曲线与实验结果基本吻合．利用含时间的ＧＳＤ方程，解决了非线型缩聚反应交联网络的模拟计算，给出了交联度随时间的变化曲线，也为凝胶点的计算提供了一种方法．     

超细二氧化硅粉体的制备

超细二氧化硅粉体的制备李中军＊刘长让王雪清ａ赵秦生（郑州大学化学化工学院，物理系ａ郑州４５００５２）（中南工业大学长沙）关键词溶胶－凝胶法，ＳｉＯ２超细粉，粉体制备１９９７－０９－２３收稿，１９９８－０３－０２修回溶胶－凝胶工艺是液相法制备超细ＳｉＯ...     

BaCe1—xRExO3—0.5x的溶胶—凝胶法合成及离子导电性

用溶胶－凝胶法合成了系列钙钛矿结构的ＢａＣｅ１－ｘＲＥｘＯ３－０．５ｘ（ＲＥ＝Ｌａ，Ｎｄ，Ｓｍ，Ｅｕ，Ｇｄ，Ｄｙ，Ｈｏ，Ｅｒ和Ｙ）复合氧化物，通过ＸＲＤ和热分析对样品结构及生成过程进行了研究．测定了不同温度下样品的交流阻抗谱，讨论了稀土离子掺杂对ＢａＣｅＯ３电性质的影响．溶胶－凝胶法比固相反应法合成温度降低了６００～８００℃，稀土掺杂使ＢａＣｅＯ３离子导电率提高了１０～４０倍．     

溶胶-凝胶法合成超细Li2+xRExSi1-xO3及其离子导电性

用溶胶－凝胶法合成了Ｌｉ２＋ｘＲＥｘＳｉ１－ｘＯ３（ＲＥ＝Ｐｒ，Ｎｄ，Ｓｍ，Ｇｄ；ｘ＝０～０．１５），用ＤＴＡ－ＴＧ，ＸＲＤ，ＴＥＭ及交流阻抗等技术对样品的结构、形貌、粒径及离子导电性等进行了观察和测试。基固淮体形成范围是０〈ｘ≥０．０９；平均粒径为１００ｎｍ；在固溶体范围内，样品电导率随掺 增加而增高；与传统的固相反应合成方法相比，该法可使样品的生成温度降低，离子导电性提高。     

微波固相法合成钠快离子导体Na5YSi4O12

应用微波方法合固相反应难于制备的Ｎａ５ＹＳｉ４Ｏ１２纯相，讨论了微波合成条件对产物的影响，与溶胶－凝胶法相比，微波法反应速率快，选择性强，合成的样品具有特异的聚集态，缺陷和微结构，从而导致离子导电活化能下降。     

新型ITSOFC复合电解质氧化铈-硫酸盐的制备和表征

制备了一种适用于中温固体氧化物燃料电池的新型两相复合电解质钐掺杂二氧化铈SDC-(Li/Na)₂SO₄. 使用XRD和SEM表征该复合电解质的物相结构和观察电解质片的截面形貌,交流阻抗法测量其400 ^oC ～ 700 ^oC的电导率. 结果表明,SDC-(Li/Na)₂SO₄由结晶相SDC和无定形相(Li/Na)₂SO₄组成. 在中温范围（500 ^oC ~ 700 ^oC）该复合电解质电导率比SDC显著增大并随温度升高呈三段变化：T<500 ^oC,表观离子传导活化能为1.28 eV;500 ^oC ～ 550 ^oC第二相硫酸盐融化,电导率激增;T≥550 ^oC,电导率又缓慢增加,活化能降为0.30 eV,与SDC和文献报道的SDC-(Li/Na)₂CO₃相比,其电导率均显著提高,如550 ^oC时SDC-(Li/Na)₂SO₄的电导率可达0.217 S·cm^-1,分别为SDC和SDC-(Li/Na)₂CO₃的25倍和3.2倍. 硫酸盐的熔融改变了离子在电解质中的传导机制,显著提高了SDC-(Li/Na)₂SO₄复合电解质的中温电导率.     

Transformation of proton-conducting Perovskite-type into fluorite-type fast oxide ion electrolytes using a CO2 capture technique and their electrical properties

Fast oxide ion conducting Ce 1- x M x O 2-delta (M = In, Sm; x = 0.1, 0.2) and Ce 0.8Sm 0.05Ca 0.15O 1.825 were prepared from the corresponding perovskite-like structured materials with nominal chemical composition of BaCe 1- x M x O 3-delta and BaCe 0.8Sm 0.05Ca 0.15O 2.825, respectively, by reacting with CO 2 at 800 degrees C for 12 h. Powder X-ray diffraction (PXRD) analysis showed the formation of fluorite-type CeO 2 and BaCO 3 just after reaction with CO 2. The amount of CO 2 gained per ceramic gram was found to be consistent with the Ba content. The CO 2 reacted samples were washed with dilute HCl and water, and the resultant solid product was characterized structurally and electrically employing various solid-state characterization methods, including PXRD, and alternating current (ac) impedance spectroscopy. The lattice constant of presently prepared Ce 1- x M x O 2-delta and Ce 0.8Sm 0.05Ca 0. 15O 1.825 by a CO 2 capture technique follows the expected ionic radii trend. For example, In-doped Ce 0.9In 0.1O 1.95 (In (3+) (VIII) = 0.92 A) sample showed a fluorite-type cell constant of 5.398(1) A, which is lower than the parent CeO 2 (5.411 A, Ce (4+) (VIII) = 0.97 A). Our attempt to prepare single-phase In-doped CeO 2 samples at 800, 1000, and 1500 degrees C using the ceramic method was unsuccessful. However, we were able to prepare single-phase Ce 0.9In 0.1O 1.95 and Ce 0.8In 0.2O 1.9 by the CO 2 capture method from the corresponding barium perovskites. The PXRD studies showed that the In-doped samples are thermodynamically unstable above 800 degrees C. The ac electrical conductivity studies using Pt electrodes showed the presence of bulk, grain-boundary, and electrode contributions over the investigated temperature range in the frequency range of 10 (-2)-10 (7) Hz. The bulk ionic conductivity and activation energy for the electrical conductivity of presently prepared Sm- and (Sm + Ca)-doped CeO 2 samples shows conductivities similar to those of materials prepared by the ceramic method reported in the literature. For instance, the conductivity of Ce 0.8Sm 0.2O 1.9 using the CO 2 capture technique was determined to be 4.1 x 10 (-3) S/cm, and the conductivity of the same sample prepared using the ceramic method was 3.9 x 10 (-3) S/cm at 500 degrees C. The apparent activation energy of the area-specific polarization resistance for the symmetric cell (Sm,Sr)CoO 3- x |Ce 0.8Sm 0.2O 1.9|(Sm,Sr)CoO 3- x was determined to be 1 eV in air.     

Enhanced ionic conductivity in an otherwise poorly conducting Ce0.90Ca0.10O(2-δ) system

A poorly conducting ionic material Ce(0.90)Ca(0.10)O(2-δ) was converted to a highly conducting composition by a codoping strategy with Sm(3+) and Gd(3+). A 50% replacement of Ca with either Sm or Gd has increased the conductivity at 550 °C of Ce(0.90)Ca(0.10)O(2-δ) from 0.0040 to 0.0169 S/cm for the Ce(0.90)Ca(0.05)Sm(0.05)O(2-δ) composition and to 0.0184 S/cm for the Ce(0.90)Ca(0.05)Gd(0.05)O(2-δ) composition. The enhancement in the oxide ion conductivity of these codoped samples has been related to the low ionic radii mismatch and the elastic strain. The extended X-ray absorption fine structure measurements on these systems confirmed that Gd, when coupled with Ca, introduced more disorder in the system, leading to lower activation energy and higher conductivity. In addition, a reduction in the Ce-O bond distance and coordination number has also been observed with codoping.     

聚醚聚氨酯/低聚醚硫酸盐电解质的导电性能

聚合物固体电解质;聚二氧戊环;聚醚聚氨酯/低聚醚硫酸盐电解质的导电性能;离子电导率;     

Superionic conductivity in lithium-rich anti-perovskites

Lithium ion batteries have shown great promise in electrical energy storage with enhanced energy density, power capacity, charge-discharge rates, and cycling lifetimes. However common fluid electrolytes consisting of lithium salts dissolved in solvents are toxic, corrosive, or flammable. Solid electrolytes with superionic conductivity can avoid those shortcomings and work with a metallic lithium anode, thereby allowing much higher energy densities. Here we present a novel class of solid electrolytes with three-dimensional conducting pathways based on lithium-rich anti-perovskites (LiRAP) with ionic conductivity of σ > 10(-3) S/cm at room temperature and activation energy of 0.2-0.3 eV. As temperature approaches the melting point, the ionic conductivity of the anti-perovskites increases to advanced superionic conductivity of σ > 10(-2) S/cm and beyond. The new crystalline materials can be readily manipulated via chemical, electronic, and structural means to boost ionic transport and serve as high-performance solid electrolytes for superionic Li(+) conduction in electrochemistry applications.     

Characterization of crystalline and amorphous content in pharmaceutical solids by dielectric thermal analysis

Morphological and thermodynamic transitions in drugs as well as their amorphous and crystalline content in the solid state have been distinguished by thermal analytical techniques, which include dielectric analysis (DEA), differential scanning calorimetry (DSC), and macro-photomicrography. These techniques were used successfully to establish a structure versus property relationship with the United States Pharmacopeia standard set of active pharmaceutical ingredient (API) drugs. A distinguishing method is the DSC determination of the amorphous and crystalline content which is based on the fusion properties of the specific drug and its recrystallization. The DSC technique to determine the crystalline and amorphous content is based on a series of heat and cool cycles to evaluate the drugs ability to recrystallize. To enhance the amorphous portion, the API is heated above its melting temperature and cooled with liquid nitrogen to ?120 °C (153 K). Alternatively a sample is program heated and cooled by DSC at a rate of 10 °C min^?1. DEA measures the crystalline solid and amorphous liquid API electrical ionic conductivity. The DEA ionic conductivity is repeatable and differentiates the solid crystalline drug with a low conductivity level (10^?2 pS cm^?1) and a high conductivity level associated with the amorphous liquid (10⁶ pS cm^?1). The DSC sets the analytical transition temperature range from melting to recrystallization. However, analysis of the DEA ionic conductivity cycle establishes the quantitative amorphous and crystalline content in the solid state at frequencies of 0.10–1.00 Hz and to greater than 30 °C below the melting transition as the peak melting temperature. This describes the “activation energy method.” An Arrhenius plot, log ionic conductivity versus reciprocal temperature (K^?1), of the pre-melt DEA transition yields frequency dependent activation energy (E _a, J mol^?1) for the complex charging in the solid state. The amorphous content is inversely proportional to the E _a where the E _a for the crystalline form is higher and lower for the amorphous form with a standard deviation of ±2%. There was a good agreement between the DSC crystalline melting, recrystallization, and the solid state DEA conductivity method with relevant microscopic evaluation. An alternate technique to determine amorphous and crystalline content has been established for the drugs of interest based on an obvious amorphous and crystalline state identified by macro-photomicrography and compared to the conductivity variations. This second “empirical method” correlates well with the “activation energy” method.     

氧化锆基固体电解质材料与温度无关的离子电导活化能

氧化锆(ZrO2)基固体电解质材料的离子电导率随温度的变化关系呈现非线性Arrhenius特征;相应地,由经典的Arrhenius公式计算得到的电导活化能是一个与温度有关的参数.本文通过对实验获得的几种Y2O3稳定立方ZrO2(YSZ) 材料的电导率－温度关系的分析,对经典的Arrhenius公式进行了修正.由修正后的Arrhenius公式计算得到的电导活化能是一个与温度无关的常数.此外,还进一步借助于物理化学中的过渡状态理论,从材料离子导电机制出发对这一与温度无关的电导活化能的合理性进行了讨论,发现这一活化能在数值上与理论计算结果吻合得很好.     

Mixed protonic-electronic conduction and dielectric response in layered vanadyl phosphate nanocomposites

The layered vanadyl phosphate, VOPO(4)2H(2)O, is employed to prepare nanosized conducting polypyrrole by redox intercalation method. Transport and dielectric properties of various compositions have been investigated by impedance technique over a temperature range of 300-120 K. Grain boundary conductivity is larger than the bulk conductivity. The conductivity reveals a discontinuity at about 212-235 K. The conductivity is predominantly ionic at high temperature and electronic at low temperature. The dielectric spectra reveal a peak in the frequency range up to 2 MHz for higher concentration of intercalated polypyrrole. The activation energy of conductivity relaxation is different from that of total conductivity derived from the impedance plot.     

High Ionic Conductivity in a LiFeO2–LiAlO2 Composite Under H2/Air Fuel Cell Conditions

New ionic conducting materials for electrolytes for electrochemical devices have been attracting the interest of researchers in energy materials. Here, for the first time, we report a conductive composite with high ionic conductivity derived from an electronic conductor α‐LiFeO₂ and an insulator γ‐LiAlO₂. High conductivity was observed in the α‐LiFeO₂–γ‐LiAlO₂ composite when prepared by a solid state reaction method. However, the conductivity enhancement in α‐LiFeO₂–γ‐LiAlO₂ composite was not observed when the two oxides were mechanically mixed. The α‐LiFeO₂–γ‐LiAlO₂ composite also exhibits O^2? or/and H⁺ ionic conduction which was confirmed through H₂/air fuel cell measurements. An exceptionally high conductivity of 0.50 S cm^?1 at 650 °C was observed under H₂/air fuel cell conditions. This provides a new approach to discover novel ionic conductors from composite materials derived from electronic conductors.