Enhancement of power output in passive micro-direct methanol fuel cells with optimized methanol concentration and trapezoidal flow channels

This work presents design, fabrication and optimization of methanol concentration and flow channel cross-sectional geometry for enhanced power output in passive micro-direct methanol fuel cells. Passive micro-direct methanol fuel cells are fabricated with flow channels in silicon having both rectang...

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Bibliographic Details
Published in:Journal of micromechanics and microengineering 2019-07, Vol.29 (7), p.75006
Main Authors: Rao, Arjun Sunil, Rashmi, K R, Manjunatha, D V, Jayarama, A, Pinto, Richard
Format: Article
Language:English
Subjects:
gas diffusion layer
methanol concentration
passive micro-direct methanol fuel cell
trapezoidal flow channels
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Summary:This work presents design, fabrication and optimization of methanol concentration and flow channel cross-sectional geometry for enhanced power output in passive micro-direct methanol fuel cells. Passive micro-direct methanol fuel cells are fabricated with flow channels in silicon having both rectangular and trapezoidal cross-sectional geometry for flow of methanol at anode and air at cathode using microelectromechanical systems (MEMS) fabrication technique. The experiments are conducted at 25 °C by feeding methanol with a flow rate of 25 μl min−1 and supply of air at cathode by air-breathing method. Results show a peak in open circuit voltage and power density at 7 M methanol concentration for passive micro-direct methanol fuel cells having both rectangular and trapezoidal cross-sectional geometry. A study of influence of silicon flow channel cross-sectional geometry on passive micro-direct methanol fuel cell performance shows for the first time that the flow channels with trapezoidal cross-section enhance the power density (6.64 mW cm−2) nearly by a factor of two compared to that of flow channels with rectangular cross-section (3.9 mW cm−2) at 7 M methanol concentration. We believe that, though our results of significant enhancement of power density with trapezoidal fuel flow channels are obtained with micro-direct methanol fuel cells as a platform, they should also be applicable to other proton exchange membrane fuel cells with ethanol or humidified hydrogen as fuel.
ISSN:0960-1317
1361-6439
DOI:10.1088/1361-6439/ab1db7