Fuel Cell Schematic

Figure 1. Fuel-cell schematic showing the different model dimensionalities. 0-D modeis are simpie equations and are not shown, the 1-D models comprise the sandwich (z direction), the 2-D modeis comprise the 1-D sandwich and either of the two other coordinate directions x or y), and the 3-D models comprise aii three coordinate directions.

Figure 11. Cathode events in an SOFC fuel cell (schematic). (As regards the free enthalpy profde (1) the configuration effect is included in the free enthalpy in the case of gas diffusion (1), while otherwise the nonconfigurational value (2, 3) is shown.71) For the purpose of a simple presentation, it is assumed that the oxygen is completely ionized when it enters the electrolyte. Cf. text for a more specific discussion.71...

Figure 1. Fuel Cell Schematic with Reconfigured Anode...

Proton exchange membrane fuel cell schematic. 10... 

Figure 5.9 Solid oxide fuel cells schematic (a) oxygen ion conducting electrolyte (b) proton conducting electrolyte, both with gas as fuel...

It is well known that for optimal performance of electrochemical energy storage and conversion devices, it is necessary to have a nonplanar electrode to increase reaction area. One requires a porous electrode with multiple phases that can transport the reactant and products in the electrode while also undergoing reaction [1] an analogy in heterogeneous catalysis is reaction through a catalyst particle [2], For traditional devices, porous electrodes are often comprised of an electrolyte (which can be solid or liquid) that carries the ions or ionic current and a solid phase that carries the electrons or electronic current. In addition, there may be other phases such as a gas phase (e.g., fuel cells). Schematically one can consider the porous electrode as a transmission-line model as shown in Fig. 1. 

PEM fuel cell schematic. (From http //www.ballard.com)... 

A microbial fuel cell schematic where bacteria in an anodic compartment can bring about oxidative conversions, while in the cathodic compartment, chemical and microbial reductive... 

Figure F.2 Hydrogen-oxygen fuel cell (schematic)...

The schematic diagram of the liquid-feed direct methanol fuel cell (DMFC) is shown in Figure 13.1. 

The concept of the reversed fuel cell, as shown schematically, consists of two parts. One is the already discussed direct oxidation fuel cell. The other consists of an electrochemical cell consisting of a membrane electrode assembly where the anode comprises Pt/C (or related) catalysts and the cathode, various metal catalysts on carbon. The membrane used is the new proton-conducting PEM-type membrane we developed, which minimizes crossover. 

Fig. 3. Schematics of gas manifolds for MCFC stacks (a) internally manifolded fuel cell stack (b) externally manifolded fuel cell stack.

One leading prototype of a high-temperature fuel cell is the solid oxide fuel cell, or SOFC. The basic principle of the SOFC, like the PEM, is to use an electrolyte layer with high ionic conductivity but very small electronic conductivity. Figure B shows a schematic illustration of a SOFC fuel cell using carbon monoxide as fuel. 

Solid electrolyte fuel cells have been investigated intensively during the last four decades.10,33 37 Their operating principle is shown schematically in Fig. 3.4. The positive electrode (cathode) acts as an electrocatalyst to promote the electrocatalytic reduction of O2 (g) to O2 ... 

In a hydrogen fuel cell, oxidation of H2 at the anode releases electrons into the circuit and produces aqueous H3 O ". Reduction of O2 at the cathode consumes electrons and generates OH , which combines with H3 O " to produce H2 O. The schematic diagram shows these processes. 

Figure 8.33. Schematic of the efficiencies of a fuel cell driven car and a conventional car with a combustion engine. Note the advantage of the fuel cell car at low load, prevailing under urban driving conditions.

Figurel. Schematic Representation of the methods utilization of natural gas in fuel cells and fuel apphcations...

Figure 3. Schematic diagram of a direct methanol fuel cell working in an acidic medium.

Figure 17.17 Schematic representation of a single-compartment glucose/02 enzyme fuel cell built from carbon fiber electrodes modified with Os -containing polymers that incorporate glucose oxidase at the anode and bilirubin oxidase at the cathode. The inset shows power density versus cell potential curves for this fuel cell operating in a quiescent solution in air at pH 7.2, 0.14 M NaCl, 20 mM phosphate, and 15 mM glucose. Parts of this figure are reprinted with permission from Mano et al. [2003]. Copyright (2003) American Chemical Society.

Figure 17.19 A membianeless ethanol/02 enz3fme fuel cell. Alcohol dehydrogenase and aldehyde dehydrogenase catalyze a stepwise oxidation of ethanol to acetaldehyde and then to acetate, passing electrons to the anode via the mediator NAD+/NADH. At the carhon cathode, electrons are passed via the [Ru(2,2 -bipyridyl)3] and biUverdin/bilimbin couples to bilirubin oxidase, which catalyzes O2 reduction to H2O. (a) Schematic representation of the reactions occruring. (b) Power/cmrent response for the ceU operating in buffered solution at pH 7.15, containing 1 mM ethanol and 1 mM NAD. Panel (b) reprinted from Topcagic and Minteer [2006]. Copyright Elsevier, 2006.

FIGURE 12.1 Schematic depiction of a biocatalytic fuel cell, with fuel oxidation by a biocatalyst (Cat) at the anode and oxidant reduction by a biocatalyst (Cat ) at the cathode, in a membraneless assembly, providing power to the load. 

Schematic of ZECA process the anaerobic hydrogen production and fuel cell system. Material flows are idealized to predominant components.

Figure 6.18 Schematic diagram of a fuel cell stack using a stabilized zirconia electrolyte.

Figure 6.6 Schematic of 500 MW class coal fueled pressurized SOFC. Reconstituted from Fuel Cell Handbook, 5th ed., Oct. 2000, USDOE.

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