TiO2掺杂Ce0.8Sm0.2O1.9材料的制备与表征

通过凝胶浇注法制备了TiO2掺杂量为0-15％（摩尔分数）的T1O2-Ce0.8Sm0.2O1.9（TixCe0.8xSm0.2O2-y，TSDC）粉体。采用X射线衍射、透射电镜对所得粉体的相组成和颗粒形貌进行了测试分析，考察了粉体的烧结性能。此外，还测定了不同组成TSDC烧结体在空气和氢气气氛中的电导率。研究结果表明：凝胶浇注所得干凝胶在较低温度（500℃）下煅烧后，TiO2和Sm2O3即能完全固溶进CeO2晶格中，形成具有单一立方相结构和纳米粒度的TSDC粉体，且粉体粒径随TiO2掺杂量的增加而增大。上述粉体具有较高的烧结活性，其成形压坯在1400℃烧结后，相对密度可达95％以上。此外，测试气氛对TSDC材料的电导率有明显的影响，在空气中，随着TiO2掺入量的增大，TSDC材料的电导率减小，而在H2气氛中，电导率则明显增大，TiO2的掺入，降低了电导活化能。     

Ce0.8Sm0.2O1.9基纳米复合材料的共沉淀合成与氧离子导电性

用化学共沉淀法制备了Ce_0.8Sm_0.2O_1.9-La_9.33Si₆O₂₆纳米复合氧离子导电材料,通过X射线衍射和透射电子显微镜对合成材料的相结构进行了分析,利用交流阻抗分析测试研究了材料的离子导电性. 结果表明,纳米复合材料的煅烧粉末的平均晶粒尺寸为20nm、烧结陶瓷体的平均晶粒尺寸为44nm;700℃时,纳米复合导电体的离子导电率为0.25Ω/cm;在整个测试温度范围内,纳米复合导电体比纯La_9.33Si₆O₂₆提高了3个以上数量级,并高于纯相Ce_0.8Sm_0.2O_1.9的导电性.     

NiO／Ce0.8Sm0.2O1.9阳极材料制备及单电池性能

本文采用柠檬酸燃烧法制备了柠檬酸与金属离子摩尔比（MRCM）为1．5的NiO／Ce0.8Sm0.2O1.9（NiO／SDC）粉体,对其相组成和形貌等进行了表征。以NiO／SDC为阳极原料,共压法制备了SOFC单电池,对其电化学性能性能进行测试。结果表明,用柠檬酸燃烧法成功制备出NiO／Ce0.8Sm0.2O1.9（NiO／SDC）粉体,NiO／SDC粉体中NiO与SDC晶体的粒度分别为10．39nm和7．01nm,粉体的分散性好,比表面积大。所制备的单电池在800℃测试温度下开路电压为0．721V,最大输出功率密度可达224．2mW／cm2。本试验的初步实验结果表明,以柠檬酸燃烧法制备的NiO／Ce0.8Sm0.2O1.9（NiO／SDC）粉体为原料制备的阳极材料所构建的SOFC单电池表现出较好的电池性能,为阳极材料的研究开拓了新的发展方向。．     

Sintering temperature, microstructure and resistivity of polycrystalline Sm0.2Ce0.8O1.9 as SOFC's electrolyte

In this work, near-completely soft-agglomerated Sm_0.2Ce_0.8O_1.9 powders have been prepared. The pellets were formed and sintered at various sintering conditions of temperature and time. It was found that the sintering conditions have significant effects on the pellet resistivity. By the measurements with the DC four-probe method, it was found that the overall resistivity of the polycrystalline Sm_0.2Ce_0.8O_1.9 material sintered at 1500°C increases linearly with the reciprocal of the average grain size. The AC impedance spectroscopy has been used to distinguish the grain resistivity and the apparent grain boundary resistivity. The brick layer microstructural model has been used to provide an estimate of the apparent grain boundary resistivity and to relate the electrical properties to the microstructural parameters. By lowering the sintering temperature to 1100–1200°C, the true grain boundary resistivity was nearly two orders lower than that sintered at 1500°C, and thus the overall resistivity decreases to about 31 ohm-cm at 700°C measurement. This makes the Sm_0.2Ce_0.8O_1.9 material capable of working as SOFC's electrolyte at temperatures lower than 700°C.     

用于制备SOFC电解质膜Sm0.2Ce0.8O1.9的合成及性能研究

分别采用硝酸盐－苷氨酸燃烧法、固相法和柠檬酸硝酸盐法制备了钐掺杂的氧化铈电解质材料Sm_0.2Ce_0.8O_1.9 (SDC).采用这三种方法合成的SDC粉末通过料浆喷涂法在多孔的NiO-SDC阳极基底上制备了SDC电解质膜.采用丝网印刷在SDC电解质膜表面制备了Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ (BSCF)新型阴极,进而制备成固体氧化物燃料电池（SOFCs）单电池.采用CHI604B电化学工作站对电池性能进行了测试.采用粒径分析仪对粉末的粒度分布进行了分析.利用扫描电镜（SEM）对合成的粉末和电池的微观结构进行了观察和研究.结果表明,柠檬酸硝酸盐法合成的SDC粉末能够满足料浆喷涂法制备SOFCs薄膜电解质的要求.     

低温水热合成制备Ce_(0.8)Sm_(0.2)O_(1.9)电解质粉体

采用水热合成方法制备了Ce_(0.8)Sm_(0.2)O_(1.9)电解质材料,水热合成的温度范围为120~180℃。使用X射线衍射、扫描电镜及交流阻抗谱技术,分别表征了电解质粉体及电解质粉体的烧结样品。研究发现,电解质粉体的晶粒尺寸在13 nm左右,在140℃合成的Ce_(0.8)Sm_(0.2)O_(1.9)粉体具有更好的烧结性能和更高的离子电导率。     

La0.3Sr0.2Mn0.1Zn0.4 oxide-Sm0.2Ce0.8O1.9 (LSMZ-SDC) nanocomposite cathode for low temperature SOFCs

Nanocomposite based cathode materials compatible for low temperature solid oxide fuel cells (LTSOFCs) are being developed. In pursuit of compatible cathode, this research aims to synthesis and investigation nanocomposite La0.3Sr0.2Mn0.1Zn0.4 oxide-Sm0.2Ce0.8O1.9 (LSMZ-SDC) based system. The material was synthesized through wet chemical method and investigated for oxide-ceria composite based electrolyte LTSOFCs. Electrical property was studied by AC electrochemical impedance spectroscopy (EIS). The microstructure, thermal properties, and elemental analysis of the samples were characterized by TGA/DSC, XRD, SEM, respectively. The AC conductivity of cathode was obtained for 2.4 Scm(-1) at 550 degrees C in air. This cathode is compatible with ceria-based composite electrolytes and has improved the stability of the material in SOFC cathode environment.     

冷冻干燥技术制备超微LiNi0.8Co0.2O2粉及其表征

采用冷冻干燥技术成功合成了层状锂离子电池正极材料LiNi0.8Co0.2O2,研究了不同煅烧温度对产物结构、微观形貌以及性能的影响.利用TG-DTA分析、X射线衍射(XRD)、场发射扫描电镜(FESEM)和激光粒度分析仪对前驱体和煅烧样品的热反应、晶体结构、微观形貌和粒度分布等进行了表征.结果表明,煅烧温度对LiNi0.8Co0.2O2晶体结构及材料性能有较大影响.750℃×5h的煅烧条件下制得的LiNi0.8Co0.2O2粉具有纳米级尺寸和窄的粒度分布,该样品的(003)晶面衍射峰强度与(104)晶面衍射峰的强度比I(003)/I(104)为1.51.晶格参数显示制得的LiNi0.8Co0.2O2样品用作锂离子电池的电极,可能会显示出良好的电化学性能.     

La0.85Sr0.15Cr0.9Ni0.1O3-δCe0.8Sm0.2O1.9作为SOFC阳极材料的研究

较低的催化活性大大地限制了La0．85Sr0．15Cr0．9Ni0．1O3-δ-（LSCN）作为直接碳氢化合物燃料SOFC阳极材料的应用．本文尝试用Pechini法合成LSCN，并按重量比1：1向其中加入纳米Ce0.8Sm0.2O1.9（SDC）作为阳极材料．经1500℃高温烧结12h后，LSCN与SDC以及电解质YSZ仍可以保持各自独立的相结构．加入SDC没能提高阳极的电导率，但由于改善了阳极电解质界面的结合状况，扩展了电极反应的活性区域，使阳极材料的极化性能有了提高．显微结构观察品示．LSCN-SDC阳极存甲烷与氧中使用时没有碳沉积现象．     

低温燃烧合成制备Ce0.8Y0.2O1.9电解质

以柠檬酸为还原剂,以硝酸盐为氧化剂,使用溶胶-凝胶低温燃烧工艺制备Ce0.8Y0.2O1.9纳米粉体,研究了溶液的凝胶化和硝酸盐与柠檬酸的摩尔比对粉体的微观结构及烧结性能的影响.结果表明:柠檬酸(CA)与金属离子(Mn )的摩尔比(nCA/nn M)和溶液的pH值决定了金属离子的络合,柠檬酸与金属离子的络合物通过氢键凝胶化.当燃烧反应中硝酸盐与柠檬酸的比值为1.5时,粉体具有很好的成型和烧结性能.将素坯在1350 ℃保温4 h,得到的烧结体晶粒尺寸为0.46 μm,相对密度95%以上,700 ℃时的离子电导率为0.034 S·cm-1.     

烧结助剂Co2O3对Ce0．8Gd0．2O1.9性能的影响

采用传统固相反应法制备陶瓷试样,借助EIS、XRD及SEM等技术手段研究了烧结助剂Co2O3对Ce.8Gd0.2O1.9(CGO)的体密度、导电性能、相组成及微观结构的影响.结果表明,当CGO中添加2.5%(质量分数)Co2O3时,可使CGO试样的烧结温度降低200℃.添加0.75%(质量分数)Co2O3时,试样的晶粒电导率明显增大,晶界电导率下降,添加量为1.0%～2.5%(质量分数)时,晶粒电导率趋于不变,晶界电导率稍微有所增加.XRD图谱表明,试样在1100～1200℃烧结时表现为CGO纯相,在1300～1400℃的较高温度烧结时,为CGO相及少量的Ce24Co11相.     

Room temperature co-precipitation of nanocrystalline CeO2 and Ce0.8Gd0.2O1.9−δ powder

This paper describes a simple method to co-precipitate CeO₂ and Ce_0.8Gd_0.2O_1.9−δ with ammonium hydroxide from solvents such as: water, ethylene glycol, ethyl alcohol and isopropyl alcohol. Characterization by Raman spectroscopy and XRD evidenced the formation of a solid solution of gadolinium-doped ceria at room temperature. Nanometric particles with crystallite size of 3.1 nm were obtained during synthesis using ethyl alcohol as solvent. This is a promising result compared with those mentioned in the literature, in which the smallest crystallite size reported was 6.5 nm.     

钴掺杂对氧化物燃料电池电解质Ce_(0.8)Y_(0.2)O_(1.9)性能的影响(英文)

采用共沉淀法制备了细的Ce0.8Y0.2O1.9(YDC)粉末,并将其应用于钴掺杂的YDC电解质材料。研究了钴元素对材料烧结性能和电性能的影响。结果表明,钴元素显著增加了材料的密度(烧结温度在1000℃时,其密度超过理论密度的98%)和电导率(750℃时0.99S/m),同时还发现小于1μm尺寸的晶粒具有高的电导率。     

Novel wet-chemical synthesis and characterization of nanocrystalline CeO2 and Ce0.8Gd0.2O1.9 as solid electrolyte for intermediate temperature solid oxide fuel cell (IT-SOFC) applications

Novel wet-chemical methods of synthesis have been adopted to synthesize nano-crystalline CeO₂ and Gd-substituted compositions aiming to explore an efficient oxide ion conducting solid electrolyte for intermediate temperature solid oxide fuel cell (IT-SOFC) applications. Nano-crystalline CeO₂ powders were synthesized by combustion method using redox mixture of cerric ammonium nitrate or cerium nitrate and maleic acid or 1,3-dimethylurea and compared with high surface area CeO₂ powders prepared by hydrothermal technique with microwave precipitated precursor from aqueous solutions of (NH₄)₂Ce(NO₃)₆ and urea. The grain size achieved by the hydrothermal technique is ∼7 nm which is smaller than that of commercial nano CeO₂ powders. Conventional or microwave sintering was used to prepare dense Ce_0.8Gd_0.2O_1.9 pellets from the ceria powders made of redox mixture of cerium nitrate, 1,3-dimethylurea (DMU) and Gd₂O₃ as the starting ingredients. The samples were characterized by X-ray diffractometry (XRD), transmission electron microscopy (TEM), diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), and ac impedance spectroscopy. The ionic conductivity measured for the pellet sintered at 1400 °C is 1 × 10⁻² and 2.4 × 10⁻² S/cm at 700 °C and 800 °C respectively.     

Coprecipitation synthesis and characterization of La0.8Sr0.2Ga(0.8-x)Mg0.2Co(x)O2.8 for intermediate temperature solid oxide fuel cell electrolytes

La0.8Sr0.2Ga(0.8-x)Mg0.2CO(x)O2.8 (LSGMC) electrolyte powders containing different amount of Co (0 < or = x < or = 0.15) were prepared by ammonium carbonate coprecipitation method. The precursors, the calcined powders, and the sintered pellets were characterized by thermogravimetry/differential thermal analysis, X-ray diffractometry, scanning electron microscopy, and an impedance analyzer. The thermal decomposition of the LSGMC precursors was completed at around 900 degrees C with the total weight loss of approximately 35%. The LSGMC samples sintered at 1350 degrees C consisted of the pure perovskite structure. The ionic conductivity was significantly improved by Co doping for the Ga-site of the La0.8Sr0.2Ga0.8Mg0.2O2.8 (LSGM) electrolytes. The ionic conductivity of LSGMC (x = 0.1) exhibited the highest values of 1.6 x 10(-1) S cm(-1) at 700 degrees C with an activation energy for the oxide-ion conduction of 0.29 eV. The results of this study indicated that the Co-doped LSGM electrolytes had excellent properties for use as an electrolyte in an IT-SOFC and the ammonium carbonate coprecipitation process could be employed as the efficient method for the preparation of the Co-doped LSGM electrolytes.     

固体氧化物燃料电池Ce_(0.8)Sm_(0.2)O_2电解质与Mn_(1.5)Co_(1.5)O_4的稳定性

本文面向管状固体氧化物燃料单电池串联中连接极与电解质界面稳定性展开研究,以氧化钐掺杂氧化铈(Ce_(0.8)Sm_(0.2)O_2,SDC)和Mn_(1.5)Co_(1.5)O_4(MCO)为原料,采用XRD、SEM和EDS来表征、探讨了SDC和MCO两种材料在不同运行和制备温度下的化学稳定性和结构稳定性。研究结果表明,SDC和MCO两种材料具有良好的化学相容性。当烧结温度低于1000℃时,难以获得致密的复合材料,而当处理温度为1400℃时,由于热力学温度过高,将导致颗粒迅速长大。     

La0.8Pb0.2Fe0.8Ni0.2O3纳米粉体的制备及其CO气敏性能研究

采用柠檬酸法制备了多晶La0.8Pb0.2Fe0.8Ni0.2O3,并对其结构、电导特性和CO气敏特性进行了研究.结果表明,该材料属正交晶系钙钛矿结构,显示了p型半导体导电特性,并且在工作温度120～340℃范围内对CO气体均具有较高灵敏度,显示出对CO气体的良好气敏性能.