Westinghouse, SOFC cathode designs

The step change in pore structure can be fabricated in discrete steps. It also allows the use of dissimilar materials for the porous structure, as used in early Westinghouse SOFC cathode designs and discussed by Thorogood et al. for oxygen transport membranes [12]. 

Any one of the three components in SOFC, the cathode, anode, or electrolyte, can provide the structural support for the cells. Traditionally, the electrolyte has been used as the support however, this approach requires the use of thick electrolytes, which in turn requires high operating temperatures. Electrode-supported cells allow the use of thin electrolytes. The Siemens—Westinghouse Corporation has developed a cathode-supported design,although this has required electrochemical vapor deposition of the YSZ electrolyte. Most other groups have focused on anode-supported cells. In all cases, it is important to maintain chemical compatibility of those parts that come in contact and to match the thermal expansion coefficients of the various components. A large amount of research has been devoted to these important issues, and we refer the interested reader to other reviews. 

In the tubular SOFC, as illustrated by the Siemens Westinghouse design shown in Fig. 13 [86], the cell components are deposited in the form of thin layers on a doped lanthanum manganite cathode tube [80, 87]. The cathode tube (2.2 cm diameter,... 

Tubular design of SOFC was initially made by Siemens Westinghouse, USA. Each tube in the mbular stack is made of a large test tube closed at one end which eliminates seal requirement. The tubular SOFC consists of two tubes, i.e. an outer tube and an iimer tube (Fig. 4.13a). The outer mbe (cell tube) consists of an inner surface and outer surface. The outer surface of the ceU tube is regarded as the anode side of the ceU and the iimer surface is considered to be the cathode side of the cell tube. The solid electrolyte is fabricated within the inner and outer surface of the cell tube. The inner tube is also known as the injection/guidance mbe. The injection tube is made up of alumina through which preheated air is injected towards the bottom of the ceU mbe. This preheated air then Uows over the cathode surface of the cell through the gap between the cell and injection mbes. 

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