Fossil fuel such as coal, oil and nature gas is the main energy resource in China even in the world. It has low power generation efficiency (approximately 30 %) and a great environmental impact, which needs to be improved. The fuel cell which could turn chemical energy directly into electrical energy is a kind of high efficiency power generation device (50 %~60 %). In all kinds of fuel cells, solid oxide fuel cell (SOFC) could use many kinds of carbon-based fuels which could be easily compatible with the existed energy resource supply system and has high power generation efficiency. All solid structures are adopted in SOFC system and excellent long term stability is observed during operation when using this kind of fuel cell. Low cost is obtained because no precious metal catalyst is used in SOFC. SOFC is especially suitable for distributed generation system and power supply system. Because of the energy structure and the superiority of rare earth resource in China, it is necessary to develop carbon-based SOFC. Improving long term stability and reducing costs are needed in the process from model operation to industrialization of SOFC. Several techniques of the carbon-based SOFC need to be focused on in the future, such as key materials, innovation by systematic integration, design and preparation of material, reaction characteristics of carbon-based fuels, cell structure, theoretical modeling and the problems of foundation science and technique in SOFC integration and operation. The measures above establish the foundation of industrialization for high efficiency, low cost and reliable carbon-based SOFC system.
Many companies worldwide are pursuing the development, manufacturing and commercialization of the solid oxide fuel cell (SOFC) technology for power generation for a variety of applications. This paper reviews and discusses the status of such development.
This review provides a close look into the world leading cathodes-supported tubular solid oxide fuel cell (SOFC) technology. It starts from the basic facts of a SOFC, where the working principle, advantages, types and applications are specifically discussed. It then focuses on cathode-supported tubular SOFCs, one important branch of SOFCs, by providing detailed information on engineering innovations, materials advances, manufacturing processes and electrical performance of both traditional cylindrical and flattened ribbed tubular cells. The review ends with a high-level summary on the SOFC generator systems manufactured and demonstrated by Siemens/Westinghouse over the past half-century.
Developing of intermediate temperature (IT) and low temperature (LT) solid oxide fuel cell (SOFC) allows metal to be used as an appropriate material for SOFC. In consistant to other types of SOFCs, metal-supported SOFC (MS-SOFC) exhibits higher electrical and thermal conductivity, better mechanical strength and lower cost, and thereby has attracted more and more attentions. Recently, MS-SOFC has developed various structures and fabrication process of supporter, electrolyte and as well as the electrodes. In this paper, the state of the art of MS-SOFC and their fabrication process are reviewed and the key concerns on MS-SOFC are also put forward.
Performance testing results of solid oxide fuel cell (SOFC) reveal complex relationship between materials, fabrication methods and performances. These results can be used in understanding various degradations in SOFC and guidance in development of materials and fabrication technologies. Standardization in testing methods contributes to building of effective and sound connections between basic research and technology development, before SOFC technology approaching pre-commercial implementation. The comparison can be made in regard to testing results from different institutions. Therefore, the standardization pushes conversion of results of basic research into real productive forces. This paper reviews the system construction, procedure formulation and standardized reporting of results for SOFC single cell testing in the world. The paper points out the importance and urgency in establishing complete standardization systems in SOFC technology for power generation in our country.
This paper summarizes the governing equations and multi-scale modeling methods for the thermal, electrical and mass transports, reformation, catalytic and sulfurization reactions in SOFCs. SOFCs have the advantage of fuel flexibility by converting a broad range of fuels such as hydrogen, carbon monoxide, methane and other hydrocarbons into electricity, but require in depth understanding of the processes of reformation, catalysis， coke and vulcanization. The transports of fuel and oxidant, heat and electricity, chemical and electrochemical reactions may be described by solving their coupled partial differential equations. The multiscale model based on these equations and the material microstructures are used to study the effects of operating conditions, material properties and geometrical configurations on the SOFC performance. Quantitative analysis and design optimization of the material compositions and the stack configurations are helpful for accelerating the development of SOFC technology.
Solid oxide fuel cells (SOFCs) are the solid-state devices for generating electricity from the chemical energy. The effect of solid oxide materials on the performance of SOFC is especially important. From the influence of materials on electrochemical performance of SOFC, this paper summarizes electrochemical characterization methods for the composition materials of SOFC briefly based on the fundamentals of electrochemistry and solid electrochemistry. Some research experience is also included in the paper, which can facilitate the further research of materials.
The conductive mechanism of crystal material, especially of the solid oxide fuel cell components is detailedly discussed in this article. Several influence factors that affect the conductivity of materials are also mentioned. Some commonly used measurements for electrolyte and electrode materials, such as total conductivity, electronic conductivity and ion conductivity measurements are introduced. Besides, the issues which should be noticed are pointed out in these measurements.
Reducing the operating temperature is critically important to promote the widespread implementation of the solid oxide fuel cell (SOFC) technology due to the associated advantages including reduced materials and processing cost as well as enhanced long-term stability. The principal approach to achieve reduction in operating temperature is to reduce the electrolyte thickness and adopt alternative electrolyte materials that exhibit much higher ionic conductivities than the state-of-the-art yttria-stabilized zirconia electrolyte at comparable temperatures. Here, electrolyte materials for low-temperature SOFC, including lanthanum gallate-based, ceria-based, and bismuth oxide-based materials， were briefly reviewed. The structure and specific properties such as effects of dopants, conductivity and chemical compatibility were discussed. The merits and drawbacks of these various electrolytes were also compared.
Solid oxide fuel cell (SOFC) has been extensively identified as one of the most promising energy conversion technologies characterized by high efficiency and environmental friendly. Low-temperature SOFC is the main direction of development of SOFC. Exploitation of new electrolytes with excellent performance is urgently required to develop low-temperature SOFC (400～600 ℃). Functional composite electrolytes are regarded as the promising electrolyte materials, and the ion conductivity is significantly improved compared to single-phase materials. The recent progress in composite electrolyte, the characteristics, type and conductive mechanism of composite electrolyte were introduced in the paper.
Solid oxide fuel cells (SOFCs) are electrochemical reactors that can directly convert the chemical energy of a fuel gas into electrical energy with high efficiency and in an environment-friendly way. The recent trends in the research of solid oxide fuel cells concern the use of available hydrocarbon fuels, such as nature gas. The most commonly used anode material Ni/YSZ cermet exhibits some disadvantages when hydrocarbons were used as fuels. Thus it is necessary to develop alternative anode materials which show a mixed conductivity under fuel conditions. This article reviews the recent developments of anode materials for SOFCs with carbon-based fuels. The future trend in this field is briefly summarized as well.
Energy crisis and environmental pollutions are the problems which the whole world is now facing for the sustainable development. Solid oxide fuel cells (SOFCs), which have been regarded as keystone for the future energy economy, have received considerable attention for their high energy conversion efficiency and low impact to environment as a mean of generating electricity. Proton conducting solid oxide fuel cells (H-SOFCs) have attracted much attention for their unique characters, such as great efficiency in fuel utilization, high electromotive force, high ionic transferring numbers and low activation energies for proton conduction. However, compared with oxygen-ion conducting SOFCs (O-SOFCs), the materials and theories on H-SOFC are just inchoate, especially for cathodes of H-SOFC. In H-SOFC, hydrogen is oxidized at the anode to form protons, which migrate through the electrolyte to the cathode, and undergo a half-cell reaction with oxygen to produce water, which makes the cathode reactions more complex compared with those of O-SOFC. Such distinguished characteristic of cathode reactions calls for intensive consideration on reaction mechanism and might lead to some special demands on the cathode materials. This review is focused on the hisrory of cathode materials for H-SOFC. The electrochemical performances and reaction models of different conduction mechanism cathode materials are summarized, providing some useful means and ways for the development and application of cathode materials for H-SOFC.
In this paper, we tried to summarize the research development of steam mathane reforming (SMR) reactions in the aspects of reforming process and reaction mechanism, catlalysts material and properties evaluation, comparison of conventional and micro reactor reaction systems, and several coupling SMR power plant systems so on. The inductive results show that the SMR coupling with solid oxide fuel cell (SOFC), especially the studies about catalysts' material for unconventional micro-reactor and the micro-reactor structure incorporate with material need more deep research work.
Solid oxide electrolysis cell (SOEC) as an environmental-friendly device can converse the electric energy into chemical energy with high efficiency. In this paper, the progress on structure and working principle of SOEC for co-electrolyzing steam and carbon dioxide to generate syngas were reviewed. The structure of SOEC, the recent development of high temperature steam/CO2 co-electrolysis from solid oxide single electrolysis cell and cell stack were also introduced. In addition, the improvement of structure and development of novel material for increasing the electrolysis efficiency of SOEC were put forward as well.