Schematic Design of a Conventional SOFC

The cathodes consist of manganites or cobaltites of lanthanum doped with divalent metal ions, for example, Lai (Srj(Mn03 (LSM) or Lax (Srj(Co03 (LSC), where 0.15 x 0.25. Apart from their 0 ion conductivity, these cathode materials also have some electronic conductivity that secures a uniform current distribution over the entire electrode. The doped lanthanum cobaltite has a higher ionic conductivity than the doped lanthanum manganite, but is more expensive and leads to problems, in particular on account of a possible chemical interaction with the electrolyte. 

The three components of the fuel cell, anode, cathode, and electrolyte form a membrane-electrolyte assembly, as, by analogy with polymer electrolyte fuel cells, one may regard the thin layer of solid electrolyte as a membrane. Any one of the three membrane-electrode assembly components can be selected as the entire fuel cell s support and made relatively thick (up to 2 mm) in order to provide mechanical stability. The other two components are then applied to this support in a different way as thin layers (tenths of a millimeter). Accordingly, one has anode-supported, electrolyte-supported, and cathode-supported fuel cells. Sometimes though an independent metal or ceramic substrate is used to which, then, the three functional layers are applied. 

Hydrogen and carbon monoxide can be used as the reactive fuels in solid oxide fuel cells. The anodic oxidation of carbon monoxide can be represented by the equation  

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