Membrane-less micro fuel cell based on two-phase flow

• Published in: Journal of power sources 2017-04, Vol.348, p.212-218
• Main Authors: Hashemi, S.M.H., Neuenschwander, M., Hadikhani, P., Modestino, M.A., Psaltis, D.
• Format: Article
• Language: English
• Subjects: Hydrogen; Mass transfer; Membrane-less; Microfluidic fuel cell (MFFC); Two-phase flow
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2017.02.079

Most microfluidic fuel cells use highly soluble fuels and oxidants in streams of liquid electrolytes to overcome the mass transport limitations that result from the low solubility of gaseous reactants such as hydrogen and oxygen. In this work, we address these limitations by implementing controlled two-phase flows of these gases in a set of microchannels electrolytically connected through a narrow gap. Annular flows of the gases reshape the concentration boundary layer over the surface of electrodes and increase the mass-transport limited current density in the system. Our results show that the power density of a two-phase system with hydrogen and oxygen streams is an order of magnitude higher than that of single phase system consisting of liquid electrolytes saturated with the same reactants. The reactor design described here can be employed to boost the performance of MFFCs and put them in a more competitive position compared to membrane based fuel cells. [Display omitted] •A microfluidic fuel cell (MFFC) with two phase streams is demonstrated.•Two-phase flows of H2 and O2 gas move parallel to each other without mixing.•Power density is one order of magnitude higher than the single-phase system.•The results open up a pathway for revisiting the use of hydrogen fuel in MFFCs.