LFFCS fuel cell

Figure 14. Design of an air-breathing laminar flow fuel cell (LFFC) showing the laminar flow profile of the anode side. Adapted with permission from Devin T. Whipple, Ranga S. Jayashree, Daniela Egas, Nicolas Alonso-Vante and Paul J.A. Kenis, Ruthenium cluster-like chalcogenide as a methanol tolerant cathode catalyst in air-breathing laminar flow fuel cells. Electrochi mica Acta 54 (2009) Copyright (2009), with permission from Elsevier.

In this chapter, the fundamentals of the membraneless laminar flow-based fuel cells (LLFCs) operation are first explained. Then, design and exploited fabrication technologies of membraneless LFFCs and the effect of flow architectures of electrodes and their arrangements on cell performance are discussed. Subsequently, reader can find more details about the proposed fuels, oxidants, and electrolytes for membraneless LLFCs. Finally, some discussions on material constraints and selections are provided. 

Membraneless LFFCs follow the basic electrochemical principles of membrane-based fuel cells. The main difference is that the role of membrane as a charge... 

Typical bulk through-plane conductivity of Nafion as proton exchange membrane is around 0.1 Scm at 100% relative humidity (RH) and room temperature [24] with typical membrane thickness of 50-200 pm. In contrast, the conductivity of 0.5 M sulfuric acid as a common supporting electrolyte is on the order of 0.2 S cm . Anode to cathode spacing in a membraneless LFFC generally ranges from 0.5 to 1.5 mm, which results in higher total ohmic losses rather than PEM fuel cells. 

Among such aqueous fuels, formic acid and methanol with energy densities of 2.08 and 4.69 kWh 1 attracted more attention for the use in membraneless LFFCs due to the ease of access and well-studied electrocatalysis. A formic acid/ O2 fuel cell has a high theoretical electromotive force of 1.45 V, while the corresponding value of methanol is 1.2 V. 

Since fuel type has significant effects on cell kinetics, only membraneless LFFCs running on formic acid or methanol is discussed for comparison. Table 9.2 provides some design features of the maximum power density of three different flow architectures running on formic acid or methanol. 

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