Fabrication of Dense Zirconia Electrolyte Films for Tubular Solid Oxide Fuel Cells by Electrophoretic Deposition

Electrophoretic deposition (EPD) is used to produce zirconia electrolyte films for tubular solid oxide fuel cells. A simple suspension chemistry (8-mol%-yttria-stabilized zirconia particles in acetic acid) yields films of similar quality to those from conventional approaches (such as electrochemical vapor deposition), but at potentially much less expense. A key factor in obtaining high-density, adherent films via the EPD approach is the application of a thin fugitive phase (carbon in this study) on the porous, doped lanthanum manganite cathode tubes prior to zirconia deposition.     

沉淀法制备中温固体氧化物燃料电池电解质材料8YSZ

以Zr （NO3）4·5H2O与Y（NO3）3·6H2O为主要原料,以柠檬酸为缓冲溶液,采用沉淀法制备电解质用8YSZ粉体,利用涂覆法在水系流延技术制备的半电池上涂覆LSM阴极得到单电池.运用XRD、TEM、激光粒度仪、SEM和电化学工作站等测试手段对粉体的物相、结构和粒度分布及单电池的结构与电性能进行了表征.研究结果表明,分散均匀、颗粒尺寸为50～100 nm、立方相8YSZ电解质在1375℃烧成具有高致密度,单电池在750℃时,以氢气和3％水蒸汽为燃料气,空气为氧化气的条件下,获得了开路电压为1.13 V,最大功率为0.93 w/cm2,欧姆阻抗为0.19Ωcm2和极化阻抗为0.65 Ωcm2的电性能.     

Cooling of a Diesel Reformate Fuelled Solid Oxide Fuel Cell by Internal Reforming of Methane: A Modelling Study

In this paper a system combining a diesel reformer using catalytic partial oxidation (CPOX) with the Solid Oxide Fuel Cell (SOFC) for Auxiliary Power Unit (APU) applications is modeled with respect to the cooling effect provided by internal reforming of methane in anode gas channel. A model mixture consisting of 80% n-hexadecane and 20% 1-methylnaphthalin is used to simulate the commercial diesel. The modelling consists of several steps. First, equilibrium gas composition at the exit of CPOX reformer is modelled in terms oxygen to carbon (O/C) ratio, fuel utilization ratio and anode gas recirculation. Second, product composition, especially methane content, is determined for the methanation process at the operating temperatures ranging from 500 ℃ to 520 ℃. Finally, the cooling power provided by internal reforming of methane in SOFC fuel channel is calculated for two concepts to increase the methane content of the diesel reformate. The results show that the first concept, operating the diesel reformer at low O/C ratio and/or recirculation ratio, is not realizable due to high probability of coke formation, whereas the second concept, combining a methanation process with CPOX, can provide a significant cooling effect in addition to the conventional cooling concept which needs higher levels of excess air.     

钙钛矿结构质子导体基固体氧化物燃料电池电解质研究进展

从适用于中低温固体氧化物燃料电池(IT-SOFCs)电解质材料的设计与改性角度出发,回顾了钙钛矿结构质子导体的发展历史、研究现状及未来研究趋势。按照钙钛矿型IT-SOFCs的结构特点,对Ce基、Zr基及Ce/Zr基电解质等质子导体做了重点介绍;指出目前Ce基陶瓷膜在稳定性方面,以及Zr基陶瓷膜在电导率和烧结活性等方面都有待提高;未来这方面研究仍主要以钡基铈酸盐、锆酸盐为主,提高电导率、增加稳定性和烧结活性等将是这类材料长期面临的困难与挑战。从质子导体的结构角度改性传统钙钛矿型IT-SOFCs电解质、探索新型钙钛矿结构质子导体以及采用新的陶瓷膜制备技术方法等将在此类电解质材料的实际应用道路上起到重要作用。     

Thin Yttrium-Stabilized Zirconia Electrolyte Solid Oxide Fuel Cells by Centrifugal Casting

A centrifugal casting technique was developed for depositing thin 8-mol%-yttrium-stabilized zirconia (YSZ) electrolyte layers on porous NiO-YSZ anode substrates. After the bilayers were cosintered at 1400°C, dense pinhole-free YSZ coatings with thicknesses of ∼25 μm were obtained, while the Ni-YSZ retained porosity. After La_0.6Sr_0.4Co_0.2Fe_0.8O₃ (LSCF)-Ce_0.9Gd_0.1O_1.95 (GDC) or La_0.8Sr_0.2MnO₃ (LSM)-YSZ cathodes were deposited, single SOFCs produced near-theoretical open-circuit voltages and power densities of ∼1 W/cm² at 800°C. Impedance spectra measured during cell tests showed that polarization resistances accounted for ∼70%–80% of the total cell resistance.     

Cell Configurations for Performance Evaluation in Planar Solid Oxide Fuel Cells

Cell configurations with asymmetric and symmetric electrode geometries and different reference electrode positions were investigated on 50 mm×50 mm planar solid oxide fuel cells (SOFC). The reliability and accuracy of the polarization performance of individual electrodes were studied with respect to the electrode geometry and the reference electrode position. The results indicate that a centrally located reference electrode creates inactive electrolyte regions in the center of the cell, pushing the equipotential lines close to the electrode–electrolyte interface region and thus introducing error in the measurement of polarization performance. The potential of reference electrodes located at the corner of the electrode coating was not stable due to the steam build-up in the reference electrode region. Cells with a symmetric electrode geometry arrangement and reference electrodes located at the side of the working electrodes, away from the receiving end of the fuel and oxidant gases, were found to be suitable for performance evaluation in planar SOFC.     

SOFC中干甲烷流量对Ni-YSZ阳极上反应的影响

为为探讨SOFC中干甲烷流量对反应的影响,采用色谱在线检测阳极尾气,总结阳极尾气的变化规律,在此基础上,分析干甲烷在固体氧化物燃料电池Ni-YSZ阳极上的反应,寻找干甲烷流量与电流对电池阳极反应影响的数学关系。依据甲烷基元反应的活化能分析反应的途径,结果表明,随电流密度以及氧离子流量的增加,干甲烷与不同电流密度下的氧离子依次发生电化学反应。这些电化学反应分别是甲烷部分氧化反应生成CO、H2并产生电子,或生成CO、H2O、H2和产生电子的反应,或产生CO、H2O和产生电子的反应,或甲烷完全氧化的电化学反应。高流量甲烷只发生消耗氧离子最少的部分氧化反应,中流量甲烷发生前两个或前三个反应。依据法拉第第一定律及反应物之间的关系,确定甲烷的低、中、高流量的判定依据分别为:v(CH4)小于等于I/(4F),v(CH4)大于等于I/(4F)以及小于等于I/(2F),v(CH4)大于等于I/(2F)。     

固体氧化物燃料电池高效利用生物质气前景分析

生物质气具有来源广、总量大的特点,其规模化利用可有效缓解我国未来能源供需紧张的矛盾,但实现规模化利用的前提是开发出适合其分散、热值低、组成变化等特点的利用技术. 本工作分析了我国生物质气的资源情况,阐述了生物质气利用技术的现状与未来发展趋势,并对固体氧化物燃料电池(SOFC)转换生物质气的技术与经济可行性进行了分析. 结果表明,SOFC能够很好地适应生物质气分散、热值低、组成变化的特点,与传统发电方式相比,SOFC发电可望具有更好的经济性. SOFC规模化利用生物质气将可缓解我国未来电力供需紧张矛盾,具有很好的环境及社会效益,发展前景广阔.     

Elastic Properties of Nickel-Based Anodes for Solid Oxide Fuel Cells as a Function of the Fraction of Reduced NiO

The changes in porosity and elastic moduli of YSZ-containing nickel-based anode materials for solid oxide fuel cells were studied as a function of the fraction of reduced NiO. Anode samples were reduced in a gas mixture of 4% hydrogen and 96% argon for different periods of time at 800°C and their Young's and shear moduli were determined afterward at room temperature using resonant ultrasound spectroscopy and impulse excitation. It was found that the magnitude of Young's and shear moduli decreased significantly with increasing fraction of reduced NiO and that the magnitude of the elastic moduli of a fully reduced Ni–YSZ anode was ∼45% lower than that of unreduced NiO–YSZ. Because the elastic moduli of NiO are close to those of Ni, the observed decrease in the magnitude of the elastic moduli was found to be caused mainly by the significant increase in the porosity of the sample as a result of NiO reduction. Expressions are presented for the amount of porosity and the magnitude of the elastic moduli as a function of the fraction of reduced NiO.     

金属支撑固体氧化物燃料电池研究进展

与传统全陶瓷结构的燃料电池不同,金属支撑固体氧化物燃料电池利用多孔金属来支撑功能阳极层–电解质层–阴极层,具有结构稳定性高、抗热快速热循环能力强,电堆组装简单,材料成本低等优势。本文分析了金属支撑固体氧化物燃料电池(SOFC)材料的选择和电池制备过程中的关键问题,并概述了金属支撑SOFC技术的研究进展。     

固体氧化物燃料电池阳极的硫毒化与再生活化

固体氧化物燃料电池(SOFC)的阳极在使用含硫廉价燃料时极易发生硫中毒现象,导致电池性能迅速衰退。本综述在介绍SOFC电极反应机制的基础上,结合近些年的文献,对不同材料的阳极硫中毒现象进行了汇总,分析了阳极硫毒化和活化规律,深入探究了硫中毒物理与化学机制,总结了硫中毒阳极的再生及活化新方法,并分析了相关再生机制。     

闪烧技术在固体氧化物燃料电池关键材料制备中的应用

闪烧技术是一种新兴的陶瓷烧结技术,因具有烧结温度低、功耗低、时间短等显著特点而受到世界范围内的广泛关注。自2010年闪烧现象被报道以来,研究人员在闪烧实验装置的搭建、不同陶瓷材料的闪烧现象、过程参数的控制及优化等方面开展了大量工作,闪烧技术得到了飞速的发展。对闪烧技术的过程参数及影响规律进行归纳和总结,重点对近年来闪烧技术在固体氧化物燃料电池领域的应用进展进行了详细介绍。     

固体氧化物燃料电池电解质材料的研究进展

固体氧化物燃料电池(SOFC)被誉为21世纪最具有发展潜力的能源材料之一,它的热效率高、燃料的适应性强,能很好地满足区域供电、供热的需要,具有重要的经济和社会意义。本文综述了SOFC电解质的研究进展,指出在诸多的电解质材料中,尽管氧化铋系电解质拥有最高的电导率,但由于其化学稳定性很差,难以获得广泛的应用;氧化钇全稳定的氧化锆(YSZ)由于其中低温的电导率较低,只适用于高温SOFC;稀土掺杂的氧化铈和LaGaO3钙钛矿材料拥有较高的中低温电导率,性质较为稳定,是适用于中低温SOFC的电解质材料。     

Development of Solid Oxide Fuel Cell Anodes Using Metal-Coated Pore-Forming Agents

Adding Ni-coated graphite particulates to a tape casting colloidal suspension is capable of creating a sintered solid oxide fuel cell anode with a critical percolation threshold for conductivity significantly lower than conventional anode materials. For example, conductivity at 800°C reached over 1200 Ω⁻¹·cm⁻¹ in these anodes at a Ni volume below the percolation threshold reported for conventional anode materials. This behavior was explained based on an "effective" Ni content, V _Nieff, which includes the graphite portion of the particle. In the green tape, V _Nieff controls the creation of a percolating network of Ni. However, when the graphite burns away, it leaves a percolated Ni network at a much lower volume fraction than would otherwise be required.     

Low-Temperature Fabrication of Oxide Composites for Solid-Oxide Fuel Cells

Composites of yttria-stabilized zirconia (YSZ) with Sr-doped LaCrO₃ (LSC) and Sr-doped LaMnO₃ (LSM) were prepared by impregnation of a porous YSZ matrix with aqueous solutions of the appropriate metal salts, followed by sintering to various temperatures. XRD measurements showed that perovskite phases formed after sintering at 1073 K, a temperature well below that at which solid-state reactions with YSZ occur. The conductivities of the LSC–YSZ and LSM–YSZ composites prepared in this way were maximized at a sintering temperature of 1373 K for LSC–YSZ and 1523 K for LSM–YSZ, although reasonable conductivities were achieved at much lower temperatures. The conductivities of the two composites increased much more rapidly with the content of the conductive oxide than has been found with conventional composites formed by mixing and sintering the oxide powders. The implications for using this approach to develop novel electrodes for SOFC applications are discussed.     

A New Vapor Deposition Method to Form Composite Anodes for Solid Oxide Fuel Cells

A solid oxide fuel cell (SOFC) is a complete solid-state energy conversion device with the potential advantages of high efficiency, silent operation, and low emissions. However, the current performance of SOFCs is still limited by a number of problems. Investigations in this field have indicated that it is imperative to fabricate efficient and compatible anodes for SOFCs to minimize polarization loss and to concurrently achieve long-term stability. In this paper, a critical review of previous studies is given and several criteria for the theoretically ideal anode are summarized. Accordingly, a newly developed vapor deposition technique, polarized electrochemical vapor deposition (PEVD), is applied to fabricate composite anodes to meet these criteria. The initial experimental results in the present study show that PEVD is capable of depositing a thin layer of yttria-stabilized zirconia on a porous metallic electrode to form a composite anode. This will not only provide continuous ionic and electronic conducting paths in the anode to reduce the overpotential loss and resistance, but also protect the metallic electrode from further sintering, vapor loss, and poisoning in the harsh SOFC operating conditions.     

质子导体基固体氧化物燃料电池的新认识

质子导体基固体氧化物燃料电池(P-SOFC/PCFC)是建立在质子传导机制上的全固态、绿色、经济的发电装置。鉴于目前固体氧化物燃料电池(SOFC)的低温化发展趋势,本综述系统分析了PCFC内部的质子传导机制,总结了目前常见的PCFC电解质和电极材料,探讨了PCFC内部质子传导通道的高效构建问题。在材料研究方面,重点分析了各类PCFC材料的设计理念和目前仍存在的问题。针对PCFC的未来发展趋势,指出开发新型的质子导体电解质和电极材料仍然是目前这一领域亟需进行的工作。     

钙钛矿型中低温固体氧化物燃料电池阴极材料研究进展

中低温固体氧化物燃料电池(IL TSOFC)的研制是固体氧化物燃料电池商业化的必然趋势,阴极材料的研制是影响其发展的关键问题之一.锈钛矿结构稀土复合氧化物材料是很有希望的中低温固体氧化物燃料电池阴极材料,文章综述了近年来ABO3型钙钛矿阴极材料的研究情况,并提出了其发展方向.     

固体氧化物燃料电池中CH4与CO2重整反应的研究

概述了有关CH4和CO2重整反应在固体氧化物燃料电池(SOFC)中的研究进展.对该反应在SOFC阳极活化及重整的反应机理进行了探讨;讨论了反应温度、压力等因素对阳极表面产生积碳的影响,分析了有利于消除积碳、促进反应进行的压力及温度范围;介绍了开发新型、高效、抗积碳的阳极材料来改善SOFC阳极积碳状况的方法,如:在阳极材料中添加不同的活化成分、助剂及选择不同载体等.     

固体氧化物燃料电池阳极材料研究进展

主要对SOFC阳极材料的最新研究进展进行综述。首先介绍了SOFC对阳极材料的基本要求,而后对目前各种阳极材料在性能方面的优势和不足进行了比较,其中较为详细地介绍了传统的金属陶瓷阳极和新型的钙钛矿型阳极的研究进展情况,最后对阳极材料的未来发展方向进行了展望。