Sealing Technology for Solid Oxide Fuel Cells (SOFC)

A variety of seals such as metal–metal, metal–ceramic, and ceramic–ceramic are required for a functioning solid oxide fuel cells (SOFC). These seals must function at high temperatures between 600 and 900°C and in oxidizing and reducing environments of the fuels and air. Among the different type of seals, the metal–ceramic and ceramic–ceramic seals require significant attention, research, and development because the brittle nature of ceramics and glasses can lead to fracture and loss of seal integrity and functionality. This paper addresses the needs and possible approaches for high-temperature ceramic–metal seals for SOFC and seals fabricated using some of these approaches. A new concept of self-healing glass seals is proposed, developed, and used for making metal—glass–ceramic seals for potential application in SOFC in order to enhance the reliability and life of a cell. In this study, glasses displaying self-healing behavior are investigated and used to fabricate seals. The performance of these seals under long-term exposure at higher temperatures coupled with thermal cycling is characterized by leak tests. The self-healing ability of these glass seals is also demonstrated by leak tests along with the long-term performance.     

Progress in Microtubular Solid Oxide Fuel Cells

The benefits of microtubular solid oxide fuel cells (SOFCs) are addressed, including increased power density, rapid start-up, and cycling performance. Several international developments are discussed, especially small portable applications, which demand fast start and multiple cycles. Extrusion is the main method for making microtubular SOFCs because improved structure and properties can result from better mixing of the component particles and coextrusion can integrate several cell components in one process step. When the tubes are <3 mm in diameter, it is shown that the power density and thermal shock resistance are much increased, with start-up in a few seconds rather than hours for planar designs, as demonstrated in a single-cell hand-held system running on butane. The problems of cycling, both thermal and redox, are then considered in detail. Thermal cycling degradation follows a fatigue curve whereas redox damage is linear with the number of cycles. New results are presented on thermal and redox cycling performance.     

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的制备工艺

介绍了不同形状和类型的固体氧化物燃料电池的各结构部件的常用制备工艺方法,包括:用于平板式支撑体制备的干压法和流延成型法,制备平板膜的涂刷、丝网印刷、离心沉积和旋涂法,管式支撑体制备的注浆成型、挤出成型、热压注、浸涂、凝胶铸模和相转换法,以及用于管式膜制备的涂刷、浸涂、料浆喷涂、电化学气相沉积和热喷涂法。针对每种工艺方法,介绍了其原理和基本工艺操作流程及其在固体氧化物燃料电池制备中的应用,讨论了工艺影响因素。     

固体氧化物燃料电池材料的研究进展

固体氧化物燃料电池（SOFC）是当今一种先进的能量转换装置，具有能量转换效率高、环境友好、燃料适用性强和无腐蚀等突出优点。该电池通常用陶瓷作组装材料，操作温度为600－1000℃。详细介绍了固体氧化物燃料电池各元件的材料，包括Y2O3稳定化的ZrO2固体电解质，Ni/稳定化ZrO2阳极，掺杂的LaMnO3阴极以及掺杂的LaCrO3连接材料等。     

以固态碳为燃料的固体氧化物燃料电池研究进展

固体氧化物燃料电池与其他燃料电池一样具有能量转化效率高、环境污染少等优点。相比于其他燃料电池,固体氧化物燃料电池在较高的操作温度下工作,可以使用气态、液态甚至固态的燃料。文章综述以固态碳为燃料的固体氧化物燃料电池研究进展,主要介绍其反应机理与电池构型,并分析其操作特点,探讨以固态碳为燃料的固体氧化物燃料电池的发展方向。     

挤出成型法制备阳极支撑型固体氧化物燃料电池

采用挤出成型法制备了添加石墨、淀粉、玉米粉3种不同阳极造孔剂的NiO-YSZ阳极支撑型管式固体氧化物燃料电池阳极基体,并用浸渍法制备了YSZ (yttria-stabilized zirconia)膜电解质,以LSM(La0.85Sr0.15MnO3)为阴极制备成单电池.以空气为氧化剂,加湿氢气(约含有体积分数为3％的...     

固体氧化物燃料电池的关键材料概述

固体氧化物燃料电池(SOFCs)因具有能量转换率高、燃料适应性强、环境友好和操作方便等优点,受到了人们的普遍关注,但是SOFCs的广泛应用还有待于其关键材料的进一步发展。本文系统的介绍了固体氧化物燃料电池对关键材料——电解质材料、阳极材料、阴极材料的要求及其研究现状,并提出了固体氧化物燃料电池在其关键材料方面的一些有待解决的问题。     

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。     

Materials Development for Advanced Planar Solid Oxide Fuel Cells

High-power density and high durability are the main targets for solid oxide fuel cell (SOFC) development at Forschungszentrum Jülich. Power density has been further increased by variation of the material composition of perovskite-based cathodes (Sr content, Co content, substoichiometry) and by optimization of the diffusion barrier (Gd-substituted ceria) between an electrolyte and a cathode. The application of dense diffusion barrier layers significantly improved the performance. The associated avoidance of SrZrO₃ formation, however, contributed only to a small extent to the improvement of durability of SOFCs with LSCF cathodes. The redox stability of anode-supported SOFCs has been addressed in two ways: (a) conventional Ni/yttria-stabilized zirconia anode substrates have been investigated to explore the limits of re-oxidation and to determine the degree of oxidation at which no damages occur. (b) Alternative anodes and anode substrates are under development, which basically consist of mixed-conducting ceramics. Avoiding the high amount of nickel decreases the probability of failure, but does not automatically lead to redox-stable anodes. The differences in the materials' properties of such ceramics in oxidizing and reducing environment are addressed.     

Implications for Using Biogas as a Fuel Source for Solid Oxide Fuel Cells: Internal Dry Reforming in a Small Tubular Solid Oxide Fuel Cell

The feasibility of operating a solid oxide fuel cell (SOFC) on biogas has been studied over a wide compositional range of biogas, using a small tubular solid oxide fuel cell system operating at 850 °C. It is possible to run the SOFC on biogas, even at remarkably low levels of methane, at which conventional heat engines would not work. The power output varies with methane content, with maximum power production occurring at 45% methane, corresponding to maximal production of H₂ and CO through internal dry reforming. Direct electrocatalytic oxidation of methane does not contribute to the power output of the cell. At higher methane contents methane decomposition becomes significant, leading to increased H₂ production, and hence transiently higher power production, and deleterious carbon deposition and thus eventual cell deactivation.     

固体氧化物燃料电池阳极研究

作为固体氧化物燃料电池(SOFC)的关键部件之一,阳极性能对SOFC性能有着十分重要的影响.本文主要对阳极研究进展进行综述,重点对阳极组织和性能方面的研究情况进行了阐述,合理选择阳极材料和制备工艺条件,优化阳极微观组织结构是获得高性能阳极的重要方面.对阳极材料选择和制备方法进行了简单的介绍.     

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。     

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。     

Strength of Anode‐Supported Solid Oxide Fuel Cells

Nickel oxide and yttria doped zirconia composite strength is crucial for anode‐supported solid oxide fuel cells, especially during transient operation, but also for the initial stacking process, where cell curvature after sintering can cause problems. This work first compares tensile and ball‐on‐ring strength measurements of as‐sintered anodes support. Secondly, the strength of anode support sintered alone is compared to the strength of a co‐sintered anode support with anode and electrolyte layers. Finally, the orientation of the specimens to the bending axis of a co‐sintered half‐cell is investigated. Even though the electrolyte is to the tensile side, it is found that the anode support fails due to the thermo‐mechanical residual stresses.     

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.     

Manufacturing Solid Oxide Fuel Cells for the Sulzer Hexis Stationary System

Concomitantly to its main objective of cost reduction per electrical kilowatt of stationary fuel cell stacks, Sulzer Hexis Ltd. (Switzerland) is developing the first commercial cogeneration solid oxide fuel cell system (SOFC) available on the market. This will be possible by fine technology optimization combined with using mass-production compatible equipment. After several years of R&D in ceramic processing techniques, Sulzer Hexis is now able to manufacture solid oxide fuel cells with competitive production costs. Moreover, these costs will be further reduced thanks to scale effect given by large production volumes. The tight collaboration with both raw material and equipment suppliers has enabled Sulzer Hexis to significantly improve both the cell performance and productivity.     

Development of Single Chamber Solid Oxide Fuel Cells (SCFC)

Single Chamber Solid Oxide Fuel Cells (SCFC) have been prepared using an electrolyte as support (Ce_0.9Gd_0.1O_1.95 named GDC). Anode (Ni‐GDC) and different cathodes (Sm_0.5Sr_0.5CoO₃ (SSC), Ba_0.5Sr_0.5Co_0.2Fe_0.8O₃ (BSCF) and La_0.8Sr_0.2MnO₃ (LSM)) were placed on the same side of the electrolyte. All the electrodes were deposited using screen‐printing technology. A gold collector was also deposited on the cathode to decrease the over‐potential. The different materials and fuel cell devices were tested under propane/air mixture, after a preliminary treatment under hydrogen to reduce the as‐deposited nickel oxide anode. The results show that SSC and BSCF cathodes are not stable in these conditions, leading to a very low open circuit voltage (OCV) of 150 mV. Although LSM material is not the more adequate cathode regarding its high catalytic activity towards hydrocarbon conversion, it has a better chemical stability than SSC and BSCF. Ni‐GDC‐LSM SCFC devices were elaborated and tested; an OCV of nearly 750 mV could be obtained with maximum power densities around 20 mW cm^–2 at 620 °C, under air–propane mixture with C₃H₈/O₂ ratio equal to 0.53.