Cell Fabrication

The fabrication processes selected for each planar SOFC cell/stack design depend on the configuration of the cells in the stack. The key step in any selected process is the fabrication of dense electrolytes. In general, ceramic fabrication processes for planar SOFCs can be classified into two groups, based on the fabrication approach for the electrolyte the particulate approach and the deposition approach. The particulate approach involves compaction of ceramic powder into cell components and densification at elevated temperatures. Examples of the particulate approach are tape casting and tape calendering. The deposition approach involves formation of cell components on a support by a chemical or physical process. Examples of the deposition approach are chemical vapour deposition, plasma spraying, and spray pyrolysis. 

At present, two main particulate processes have been developed for the fabrication of planar SOFCs tape casting [9] and tape calendering [10]. Both of these processes have been shown to be capable of making cells with electrolyte layers of various thicknesses including thin YSZ electrolytes on electrode supports. 

Tape casting. Tape casting is a common method for manufacturing thin, flat sheets of ceramics and has been used to fabricate various components for planar SOFCs. The tape casting process involves making of a layer of slip (ceramic 

I ifjure H.8 Aiwde-supporled cell fabricated by tape calenderiny. 

Other particulate processes such as pressing and extrusion have also been considered or developed for fabricating planar SOFC cell components. 

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It is clear from Table 7 that the undivided cell has considerable power usage savings over the divided cell operation. Also, there are no membrane costs, and cell fabrication is much cheaper. In addition, it was possible to simplify the product recovery in the undivided cell process. 

Duffy NW, Lane DW, Ozsan ME, Peter LM, Rogers KD, Wang RL (2000) Structural and spectroscopic studies of CdS/CdTe heterojunction cells fabricated by electrodeposition. Thin Sohd Films 361 314-320... 

FABRICATION AND TESTING OF CIS SOLAR CELLS 6.5.1 Cell Fabrication at GRC... 

Figure 6.31. Light I-V characteristics of solar cells fabricated with AACVD-deposited CuInS2 films.

TABLE 6.5. AMO Output Characteristics of Solar Cells Fabricated With AACVD-Deposited CuInS2 Films... 

The general requirements for an SOFC anode material include [1-3] good chemical and thermal stability during fuel cell fabrication and operation, high electronic conductivity under fuel cell operating conditions, excellent catalytic activity toward the oxidation of fuels, manageable mismatch in coefficient of thermal expansion (CTE) with adjacent cell components, sufficient mechanical strength and flexibility, ease of fabrication into desired microstructures (e.g., sufficient porosity and surface area), and low cost. Further, ionic conductivity would be beneficial to the extension of... 

In addition to the performance and durability of the fuel cells fabricated, cost is also an extremely important consideration in the decision of whether or not to adopt... 

Liu Y and Liu M. Porous electrodes for low-temperature solid oxide fuel cells fabricated by a combustion spray process. J. Am. Ceram. Soc. 2004 87 2139-2142. 

Cho et al. [140] examined the performance of PEM fuel cells fabricated using different catalyst loadings (20, 40, and 60 wt% on a carbon support). The best performance—742 mA/cm at a cell voltage of 0.6 V— was achieved using 40 wt% Pt/C in both anode and cathode. Antonie et al. [28] studied the effect of catalyst gradients on CL performances using both experimental and modeling approaches. Optimal catalyst utilization could also be achieved when a preferential location of Pt nanoparticles was close to the PEM side ... 

Wilson, M. S., Valerio, J. A., and Gottesfeld, S. Low platinum loading electrodes for polymer electrolyte fuel cells fabricated using thermoplastic ionomers. Electrochimica Acta 1995 40 355-363. 

Cho, Y. H., Yoo, S. J., Cho, Y. H., Park, H. S., Park, I. S., Lee, J. K., and Sung, Y. E. Enhanced performance and improved interfacial properties of polymer electrolyte membrane fuel cells fabricated using sputter-deposited Pt thin layers. Electrochimica Acta 2008 53 6111-6116. 

Very little work (relative to research of electrode materials and electrolytes) is directed toward characterizing and developing new separators. Similarly, not much attention has been given to separators in publications reviewing batteries.A number of reviews on the on cell fabrication, their performance, and application in real life have appeared in recent years, but none have discussed separators in detail. Recently a few reviews have been published in both English and Japanese which discuss different types of separators for various batteries. A detailed review of lead-acid and lithium-ion (li-ion) battery separators was published by Boehnstedt and Spot-nitz, respectively, in the Handbook of Battery Materials. Earlier Kinoshita et al. had done a survey of different types of membranes/separators used in different electrochemical systems, including batteries."... 

Figure 3. Mesoscale fuel cell fabricated by Case Western Reserve University. (Reprinted with permission from ref 63. Copyright 2001 Elsevier.)...

Cell C — a cell fabricated from rectangular glass tubing (Vitro Dynamics, Inc., Rockaway, NJ) as described elsewhere (1). 

Krebs FC, Tromholt T, Jorgensen M (2010) Upscaling of polymer solar cell fabrication using full roll-to-roll processing. Nanoscale 2 873... 

A 13.4% efficient cell fabricated by close space sublimation of CdTe on CD CdS was reported in 1991 [3], followed by a 14.5% cell a year later by the same gronp [4]. The CdS thickness was between 50 and 150 nm. The cells were illuminated throngh the tin oxide/glass, which was used as the substrate for the CdS deposition, and this geometry has been used ever since for these cells. 

The effect of this Cd/NHs treatment on the PV properties are very marked. While cells fabricated without a buffer layer [ZnO sputtered directly on the CI(G)S] are very poor, with all parameters very low, the same cells, but subjected to the Cd/NHs treatment before ZnO deposition, are very much better, and in fact the efficiencies are only a little lower than CD CdS cells, due to lower Voc (Isc is actually often higher due to the better blue response in the absence of CdS). This is a particularly important result since it shows that the main role of the buffer layer is not related to the specific properties of the CdS itself, but rather to nearsurface modification of the CI(G)S. Substitution of Zn for Cd in the Cd/NHs treatment gave comparable results [15]. This is in contrast to the use of CD ZnS, which was inferior to that of CdS, although not necessarily by much (see Section 9.1.4.5). 

Besides ruthenium complexes, rhenium complexes were also used as the photosensitizers in photovoltaic cells. Bulk heterojunction photovoltaic cells fabricated from sublimable rhenium complexes exhibited a power conversion efficiency of 1.7%.75,76 The same rhenium complex moiety was incorporated into conjugated polymer chains such as polymer 16a c (Scheme 9). Fabrication of devices based on conjugated rhenium containing polymers 17a c and SPAN by the LbL deposition method was reported.77 The efficiencies of the devices are on the order of 10 4%. 

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