SOFC cost-effective

The final chapter addresses the cross-cutting issue of materials processing for SOFC applications. The challenges in developing materials that satisfy the stringent materials property requirements is further complicated by the need to fabricate the materials in the desired shapes and with the desired microstructures. The production of a cost-effective SOFC requires compromises between materials properties and processing methods to produce materials with adequate properties at an acceptable cost. 

Winkler, W., Cost effective design of SOFC-GT, in Proceedings 6th International Symposium on SolidOxideFuel Cells, Honolulu, USA, S.C. Singhal, M. Dokiya(Eds.), The Electrochemical Society, Pennington, NJ, 1999, pp. 1150-1159. 

With respect to the marketplace, SOFC and SOFC/gas turbine hybrids are potentially an attractive basis for an efficient, clean, cost-competitive DG system, but they do not depend on having 1I2 fuel. However, they could facilitate a transition to a H2 economy by making use of H2 for distributed electricity and CHP, while other fuel cells for vehicles are becoming cost-effective, reliable, and efficient. It is important for the DOE to monitor the milestones and goals of the SECA Program and to fully fund it. 

In SOFCs, the difference in chemical potential or activity of oxygen across the electrolyte surfaces provides the electromotive force, and thus the electrical potential. Extensive research over the past decades has resulted in the development of cost-effective processes for the fabrication of thin and dense electrolyte layers. YSZ has been considered one of the best choices for high-temperature applications (>650°C) because of its feasibility of fabrication of a thin membrane, reasonable ionic conductivity, large ionic domain, and, most importantly, chemical and mechanical stability... 

The cost of the simultaneous deposition process is also moderate although the capital cost of the equipment can exceed 500,000. With powder ceramic processing the powder costs can exceed 2000 /Kg plus the cost of other components and the multi-step processes to produce laminated systems from fine powders which are moderate or high in value. The potential cost effectiveness of direct processing of SOFC elements by EBPVD appears to offer an attractive alternative to other fine powder consolidation technologies. 

Lowering the resistance of the electrolyte is one of the objectives important for the development of the performance of IT-SOFCs. To meet this objective the cost effective technology should be developed, which allows preparation of dense electrolyte layer of 1-10 im thick. 

In recent decades, the operation temperature of SOFCs was reduced to lower than 1,073 K. In such a temperature zone, metallic intercormectors can be applied instead of oxides [4,5]. The application of metallic materials is expected to reduce the materials cost effectively. In addition, they have high thermal and electrical conductivities in comparison with oxide ceramics, which has an advantage of designing compact SOFC systems. 

The replacement of traditional ceramic intercoimects with metallic components to create SOFC stacks offers significant improvements in SOFC performance along with reduced cost. However, understanding the degradation processes in terms of corrosion and chromium migration is critical for developing cost effective SOFCs. Raman spectroscopy is particularly sensitive to the relevant oxides and corrosion processes. 

SOFC in 100 kW to MW-range with cost-effective constniction materials... 

Upon exposure to higher p02 at SOFC temperatures, the cmiductivity decreases slowly [96]. This is observed in Fig. 3.19 as the significant decrease in conductivity for all of the samples as the /7O2 is increased above 10 " atm. The slow kinetics associated with this may be related to slow cation diffusion [101] and/or low oxygen mobility in these materials [103]. Slow reoxidation kinetics are beneficial to application in the SOFC anode where accidental and occasional exposure of the anode material to air may be expected. Of course, this assumes that a suitable and cost-effective cell synthesis procedure can be derived to initially form these highly conductive states. Furthermore, slow reoxidation may indicate slow surface oxygen exchange and low hydrocarbon oxidation activity. 

The current state-of-the-art SOFC anode-supported cells based on doped zircona ceramic electrolytes, ceramic LSM cathodes, and Ni/YSZ cermet anodes are operated in the temperature range 700-800°C with a cell area specific resistance (ASR) of about 0.5 O/cm at 750°C. Using the more active ceramic lanthanum strontium cobalt ferrite (LSFC)-based cathodes, the ASR is decreased to about 0.25 Q/cm at this temperature, which is a more favorable value regarding overall stack power density and cost-effectiveness. 

European Institute for Energy Research (EIFER) (2008) Final report on evaluation on the sustainability of the stacks produced in the project. Real-SOFC Project, Realising reliable, durable energy efficient and cost effective SOFC systems. Integrated EU project under the 6th framework programme... 

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