Toward Carbon Foam Structures in a Microfluidic Fuel Cell

ASME 2011 9th International Conference on Fuel Cell Science, Engineering and Technology ◽

10.1115/fuelcell2011-54439 ◽

2011 ◽

Author(s):

D. Fuerth ◽

A. Bazylak

Keyword(s):

Fuel Cell ◽

Carbon Foam ◽

Carbon Paper ◽

Cell Potential ◽

Redox Species ◽

Flow Through ◽

Microfluidic Fuel Cell ◽

And Performance ◽

Future Work ◽

Vanadium Redox

In this paper, the design and performance of a flow-through microfluidic fuel cell with carbon-based electrodes is presented. Our preliminary results include the use of Toray TGP-H-090 carbon paper as our porous carbon electrodes. The cell exhibited a maximum power density of 0.12 mW/cm2 and an open cell potential of 1.2 V, and a discussion of this performance is provided. The vanadium redox species is employed as fuel (V2+) and oxidant (VO2+) due to its ability to naturally react on bare carbon, eliminating the need for additional catalysts. Our future work will include the investigation of carbon foam electrodes with grades of 45, 80, and 100 pores per linear inch (PPI).

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Modeling of Microfluidic Fuel Cells With Flow-Through Porous Electrodes

ASME 2010 8th International Fuel Cell Science, Engineering and Technology Conference: Volume 1 ◽

10.1115/fuelcell2010-33220 ◽

2010 ◽

Author(s):

Ali Ebrahimi Khabbazi ◽

Mina Hoorfar

Keyword(s):

Fuel Cell ◽

Solid Phase ◽

Porous Electrode ◽

Porous Electrodes ◽

Metal Catalyst ◽

Redox Species ◽

Redox Couples ◽

Flow Through ◽

Microfluidic Fuel Cell ◽

Vanadium Redox

This paper presents a modeling of a microfluidic fuel cell with flow-through porous electrodes using vanadium redox couples as the fuel and oxidant. There are advantages associated with the use of vanadium redox species in microfluidic fuel cell: 1) vanadium redox couples have the possibility of producing high open-circuit potential (up to 1.7 V at uniform PH [1]); 2) they have high solubility (up to 5.4 M) which causes more species available to the electrodes; 3) they do not require metal catalyst for electrochemical reactions so the reactions take place on the bare carbon electrodes. This characteristic of the vanadium redox couple make them a great candidate as reactants as they do not need expensive catalyst coatings on the electrodes. The fuel and the oxidant can be brought into contact with the electrode in two different ways: flowing over the electrodes or flowing through the electrodes. In the presented fuel cell design, the vanadium redox species are forced to flow through the porous electrodes. They finally come to meet each other in the middle microchannel and establish a side-by-side co-laminar flow traveling down the channel. In this paper, the effect of the inlet velocity and electrode porosity has been investigated. As it is expected, the higher velocity results in the higher power densities. For the porosity, however, there is an optimum value. In essence, there is a trade-off between the available electrode surface area and electric conductivity of the solid phase (i.e., the porous carbon electrode). The modeling shows that a porous electrode with a 67% porosity results in the highest power output.

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Up-Scaled Microfluidic Fuel Cells With Porous Flow-Through Electrodes

Journal of Fluids Engineering ◽

10.1115/1.4023449 ◽

2013 ◽

Vol 135 (2) ◽

Cited By ~ 17

Author(s):

D. Fuerth ◽

A. Bazylak

Keyword(s):

Fuel Cells ◽

Fuel Cell ◽

Surface Area ◽

Electrode Surface ◽

Porous Electrode ◽

Porous Electrodes ◽

Carbon Paper ◽

Platinum Black ◽

Flow Through ◽

Microfluidic Fuel Cell

In this work, an experimental microfluidic fuel cell is presented with a novel up-scaled porous electrode architecture that provides higher available surface area compared to conventional microfluidic fuel cells, providing the potential for higher overall power outputs. Our proof-of-concept architecture is an up-scaled flow-through fuel cell with more than nine times the active electrode surface area of the flow-through architecture first proposed by Kjeang et al. (2008, “A Microfluidic Fuel Cell With Flow-Through Porous Electrodes,” J. Am. Chem. Soc., 130, pp. 4000–4006). Formic acid and potassium permanganate were employed as the fuel and oxidant, respectively, both dissolved in a sulfuric acid electrolyte. Platinum black was employed as the catalyst for both anode and cathode, and the performances of carbon-based porous electrodes including cloth, fiber, and foam were compared to that of traditional Toray carbon paper (TGP-H-120). The effects of catalyst loading were investigated in a microfluidic fuel cell containing 80 pores per linear inch carbon foam electrodes. A discussion is also provided of current density normalization techniques via projected electrode surface area and electrode volume, the latter of which is a highly informative means for comparing flow-through architectures.

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