Solid Oxide Fuel Cell electrolyte, alternative

Intermediate Temperature Solid Oxide Fuel Cell (ITSOFC) The electrolyte and electrode materials in this fuel cell are basically the same as used in the TSOFC. The ITSOFC operates at a lower temperature, however, typically between 600 to 800°C. For this reason, thin film technology is being developed to promote ionic conduction alternative electrolyte materials are also being developed. 

Decreasing operation temperature of solid oxide fuel cells (SOFCs) and electrocatalytic reactors down to 800-1100 K requires developments of novel materials for electrodes and catalytic layers, applied onto the surface of solid electrolyte or mixed conducting membranes, with a high performance at reduced temperatures. Highly-dispersed active oxide powders can be prepared and deposited using various techniques, such as spray pyrolysis, sol-gel method, co-precipitation, electron beam deposition etc. However, most of these methods are relatively expensive or based on the use of complex equipment. This makes it necessary to search for alternative synthesis and porous-layer processing routes, enabling to decrease the costs of electrochemical cells. Recently, one synthesis technique based on the use... 

Goodenough JB (2003) Oxide-ion electrolytes. Annu Rev Mater Res 33 91-128 Goodenough JB, Huang Y (2007) Alternative anode materials fin solid oxide fuel cells. J Power Sources 173 1... 

As constructive alternatives, SOFCs can be used as planar or tubular SOFCs, respectively. In the past period, the planar SOFCs become more attractive for the commercialization because of their high power density and low production costs [2]. The planar SOFCs may also be divided into (i) electrolyte-supported and (ii) anode-supported solid oxide fuel cells. Also, more and more attention was focused on solid oxide fuel cells operating at low and/or intermediate temperatures. The decrease of temperature demands an electrolyte with higher ionic conductivity than, for example, the conventional YSZ. 

On the other hand, there is a great demand for alternative fuel cells operating at moderate temperatures. In this context, intermediate temperature (400-800 °C) fuel cells are very attractive since they combine the advantages of both high- and low-temperature fuel cells such as fast electrode kinetics, fuel flexibility, and fewer degradation problems [7]. Furthermore, the tendency of lower temperatures makes conventional ceramic fuel cells (mainly solid oxide fuel cells SOFCs) a leading candidate for applications such as stationary power plants but also the possibility to replace internal combustion engines in vehicles [8]. Ceramic fuel cells based on ceria-carbonate salt composite electrolytes have been intensively studied for the past decade... 

Abstract In this chapter, we highlight some critical aspects of materials for use in solid oxide fuel cells. In relation to oxide ion conducting electrolytes, we address topics including clustering of defects in zirconias and the resultant limitations on ionic conductivity. We also discuss the ionic conduction window for various electrolyte systems. The positive and negative attributes of different anode materials are considered, highlighting the opportunities for alternative materials to be utilised in certain parts of the SOFC system. Some suitable system concepts are presented and a strategy to optimise performance and durability in the same electrode structures is presented. 

Another area that has been of interest since the development of this field is that of metal oxides. Simple metal oxides such as MgO provide a test bed for new methods. More complex oxides have attracted much interest for their commercially important properties—solid electrolytes, ferroelectrics, catalysts, semiconductors, superconductors, multiferroics. Relatively simple calculations can, for example, track the path of ions through ionic conductors and suggest alternative solids for fuel cells or batteries. Solids with interesting electrical and magnetic properties such as high Tc superconductors and solids showing colossal magnetoresistance (CMR) have been... 

It is usual to operate an aqueous-medium fuel cell under pressure at temperatures well in excess of the normal boiling point, as this gives higher reactant activities and lower kinetic barriers (overpotential and reactant diffusion rates). An alternative to reliance on catalytic reduction of overpotential is use of molten salt or solid electrolytes that can operate at much higher temperatures than can be reached with aqueous cells. The ultimate limitations of any fuel cell are the thermal and electrochemical stabilities of the electrode materials. Metals tend to dissolve in the electrolyte or to form electrically insulating oxide layers on the anode. Platinum is a good choice for aqueous acidic media, but it is expensive and subject to poisoning. 

The well-established ceramic fuel cell concepts discussed above comprise oxide ion conducting oxides as solid electrolyte separator material, distinct electrocat-alytically active electrodes made from metals or mixed conducting oxides and well separated gas chambers. Alternative approaches are based on electrolytes... 

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