Electrodes single-oxide fuel cell

Kanamura K., Yoshioka S., Takehara Z., 1991. Dependence of entropy change of single electrodes on partial pressure in Solid Oxide Fuel Cells. Journal of the Electrochemical Society 138(7), 2165-2167. 

Abstract Single-chamber solid oxide fuel cells (SC-SOFCs) immerse the entire cell in a mixture of fuel and oxidizer gases within a single chamber, which eliminates the need for high temperature sealant, simplifies construction, and increases reliability over traditional double-chamber cells. However, there are challenges, such as low fuel utilization and electrode catalytic selectivity, that need to be overcome. This brief review paper looks at recent improvements in materials, processing, and operation of SC-SOFCs, which are rapidly approaching the performances of the double-chamber fuel cells and may become attractive for specific fuel cell applications. 

A single-chamber solid oxide fuel cell (SC-SOFC), which operates using a mixture of fuel and oxidant gases, provides several advantages over the conventional double-chamber SOFC, such as simplified cell structure with no sealing required and direct use of hydrocarbon fuel [1, 2], The oxygen activity at the electrodes of the SC-SOFC is not fixed and one electrode (anode) has a higher electrocatalytic activity for the oxidation of the fuel than the other (cathode). Oxidation reactions of a hydrocarbon fuel can... 

It is well known that catalyst support plays an important role in the performance of the catalyst and the catalyst layer. The use of high surface area carbon materials, such as activated carbon, carbon nanofibres, and carbon nanotubes, as new electrode materials has received significant attention from fuel cell researchers. In particular, single-walled carbon nanotubes (SWCNTs) have unique electrical and electronic properties, wide electrochemical stability windows, and high surface areas. Using SWCNTs as support materials is expected to improve catalyst layer conductivity and charge transfer at the electrode surface for fuel cell oxidation and reduction reactions. Furthermore, these carbon nanotubes (CNTs) could also enhance electrocatalytic properties and reduce the necessary amount of precious metal catalysts, such as platinum. 

This negative potential is easy to understand and is actually used today in the single-chamber fuel cell [14] oxygen is consumed by the catalytic reaction of CH3OH oxidation much faster on the Pt catalyst-electrode than on the Ag counterelectrode (Ag is also a catalyst for CH3OH oxidation and partial oxidation, but much less... 

Ozin and coworkers recently extended the supra-molecular I S+ assembly into the synthesis of binary mesoporous yttrium oxide-stabilized-zirconium oxide materials.These materials were synthesized by a modified sol-gel method under basic conditions, where zirconium ethoxide and yttrium acetate were used as the precursors for the transition metal oxides, and CTAB was used to form the supramolecular templates. The use of ethylene glycol with coordinating capability as a cosolvent may play a role in controlling the hydrolysis rate and solubility of zirconium(IV) and yttrium(III). This synthesis strategy is similar to that of so-called polymerizable-complex method, which was widely used to prepare multicomponent single-phase oxides. The yttrium content in these binary materials can be tuned from 12-56 wt%, and no phase segregation of yttrium and zirconium oxides was observed. These materials could be applied in designing new solid oxide fuel-cell electrode materials. 

In the following Sections the most relevant studies of alcohol oxidation in both half cells and single monoplanar fuel cells using electrodes containing Pd-based electrocatalysts are reviewed. 

Miniaturization limits for single-chamber micro solid oxide fuel cells with coplanar electrodes. J. Power Sources, 194 (2), 941-949. 

Ahn, S.-J., Lee, J.-H., Kim, J., and Moon, J. (2006) Single-chamber solid oxide fuel cell with micropattemed interdigitated electrodes. Electrochem. Solid-Stau Lett., 9 (5), A228-A231. 

Singlemicro solid oxide fuel cells study of anode and cathode materials in coplanar electrode design. Solid State Ionics, 181 (5-7), 332-337. 

The central element of the solid oxide fuel cell stack is the SOFC cell which consists of the fuel electrode (anode), the oxygen electrode (cathode), and the ionconducting electrolyte. To reach the desired electrical voltage, single cells are stacked (cf. Fig. 21.11). They are separated by interconnects (plates) and sealed by glass ceramics. 

In this code, a 1-dimensional electrochemical element is defined, which represents a finite volume of active unit cell. This 1-D sub-model can be validated with appropriate single-cell data and established 1-D codes. This 1-D element is then used in FLUENT, a commercially available product, to carry out 3-D similations of realistic fuel cell geometries. One configuration studied was a single tubular solid oxide fuel cell (TSOFC) including a support tube on the cathode side of the cell. Six chemical species were tracked in the simulation H2, CO2, CO, O2, H2O, and N2. Fluid dynamics, heat transfer, electrochemistry, and the potential field in electrode and interconnect regions were all simulated. Voltage losses due to chemical kinetics, ohmic conduction, and diffusion were accounted for in the model. Because of a lack of accurate and detailed in situ characterization of the SOFC modeled, a direct validation of the model results was not possible. However, the results are consistent with input-output observations on experimental cells of this type. 

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