(490e) Investigation of Cathode Contaminants within Microfluidic and Laminar-Flow Fuel Cells

Fuel cells hold promise as alternative power sources due to their ability to bypass Carnot efficiency limitations by directly converting chemical energy into electrical energy.  However, the use of hydrogen fuel is not compatible with existing distribution infrastructure [1].  Liquid fuels such as methanol, ethanol, and sodium borohydride offer an alternative energy-dense means to produce power, but losses from fuel crossover have limited the usable fuel concentrations at the anode [2].  Quantification of these losses and/or mitigation of crossover losses is necessary for optimal fuel cell design.

Previously, we developed pH-flexible flowing electrolyte microfluidic fuel cells and laminar-flow fuel cells, which use an external reference electrode to individually analyze cathode and anode performance [3,4].  This microfluidic configuration combines the versatility of a traditional three electrode cell with the conditions found in an operating fuel cell, allowing for in-situ studies of catalyst and electrode performance.  External control over the flowing electrolyte stream allows for controlled introduction of contaminants and maintains their concentrations over the course of experimentation [5].

Here, we present our work on the effects of fuels such as methanol, ethanol, and sodium borohydride as cathode contaminants in acidic and alkaline fuel cells.  The effects of these contaminants on various cathode catalysts such as Pt, Ag, and Cu triazole are quantified.  We also investigate the effect of cathode oxidizers such as hydrogen peroxide at the anode.  Understanding of crossover losses in an operating fuel cell has the potential to reduce the cost of fuel cell systems and enable contaminant-resistant catalyst design.

[1] L. Carrette, K. A. Friedrich, U. Stimming, ChemPhysChem, 2000, 1, 162-193

[2] J .S. Spendelow, A. Wieckowski, Physical Chemistry Chemical Physics, 9, 2007, 2654

[3] F. R. Brushett, W. P. Zhou, R. S. Jayashree, P. J. A. Kenis, Journal of the Electrochemical Society, 2009, 156, B565

[4] E. R. Choban, L. J. Markoski, A. Wieckowski, P. J. A. Kenis, Journal of Power Sources, 2004, 128, 54-60

[5] M. S. Naughton, F. R. Brushett, P. J. A. Kenis, Journal of Power Sources, 2011, 196, 1762-1768