Numerical modelling of CO poisoning induced sustained oscillations in the anode potential of a PEM fuel cell

LEVITÁN DAVID; GIUNTA PABLO; LABORDE MIGUEL ÁNGEL

Buenos Aires

Congreso; 20 th Topical Meeting of the International Society of Electrochemistry: Advances in Lithium and Hydrogen Electrochemical Systems for Energy Conversion and Storage; 2017

International Society of Electrochemistry

A dynamic 1-D model for the simulation of the oscillatory behaviourin the potential of the anode of a PEM fuel cell under constantcurrent conditions and CO impurities in the H_2 inlet is proposed.The model is built upon the electrostatic, chemical/kinetic andthermodynamic principles underlying the operation of a fuel cell,without any empirical fitting variables introduced. The model is ableto capture the fenomenon of the oscillatory behaviour while givinginsight into the effect of the composition and interconnectedkinetics between the HOR and CO-electrooxidation. Three electrochemical steps are used for the HOR: Tafel non-potentialdependent adsorption of Hydrogen atoms, Heyrovsky potential dependentadsorption-oxidation and Volmer oxidation. A proposed by Zhang[1],three steps are also provided for CO-electrooxidation: CO adsorption,potential dependent H2O adsorption-oxidation and irreversible COelectrooxidation.Following the work of Franco et al.[2], two regions of theelectrochemical double layer are modelled. In the ?diffuse layer?farther away from the electrode an explicit system of differentialequations is derived for the electrostatic potential and protonicconcentration.To account for the presence of different species of dipole moleculeson the surface of the electrode several modifications have been madefrom the model proposed by Franco et al. for the ?compact layer?of adsorbed molecules.In agreement with previous works by Zhang[1], Mota and Kadyk[3-4],two different time characteristics for the dynamics of the system arefound.References:[1]J. Zhang and R. Datta, J. Elec. Soc, 249, 11(2002)[2]A.A. Franco, P. Schott, C. Jallut B. and Maschke, Fuel Cells, 7,2 (2007)[3]A. Mota, P. P. Lopes, E. A. Ticianelli, E. R. Gonzalez and H.Varela, J. Elec. Soc., 157, 9 (2010)[4]T. Kadyk, S. Kirsch, R. Hanke-Rauschenbach and K. Sundmacher,Electrochimica Acta. 56 (2011)p { margin-bottom: 0.1in; direction: ltr; color: rgb(0, 0, 0); line-height: 120%; }p.western { font-family: "Times New Roman", serif; font-size: 10pt; }p.cjk { font-family: "Times New Roman", serif; font-size: 10pt; }p.ctl { font-family: "Times New Roman", serif; font-size: 10pt; }p { margin-bottom: 0.1in; direction: ltr; color: rgb(0, 0, 0); line-height: 120%; }p.western { font-family: "Times New Roman", serif; font-size: 10pt; }p.cjk { font-family: "Times New Roman", serif; font-size: 10pt; }p.ctl { font-family: "Times New Roman", serif; font-size: 10pt; }p { margin-bottom: 0.1in; direction: ltr; color: rgb(0, 0, 0); line-height: 120%; }p.western { font-family: "Times New Roman", serif; font-size: 10pt; }p.cjk { font-family: "Times New Roman", serif; font-size: 10pt; }p.ctl { font-family: "Times New Roman", serif; font-size: 10pt; }