Polarization curve cathode catalyst layer

Polarization curves for a PEM fuel cell with different cathode catalyst layers. (Reproduced from Zhang, X. and Shi, P. Electrochemistry Communications 2006 8 1229-1234. With permission from Elsevier.)... 

Fig. 46 Simultaneous fit to four polarization curves for a PEFC with 300-mm-thick cathode GDL and 7.5-pm-thick cathode catalyst layer applied to the membrane surface [12]. Different cathode feed stream compositions were used and a simultaneous fit demanded for all characteristics using the same physical and transport parameters for the GDL and the catalyst layer [13]. Fitted cathode parameters were ...

Figure 1.3 Schematic for the calculation of voltage loss in a fuel cell (for discussion see text). ACL and CCL are the abbreviations for the anode and cathode catalyst layers, respectively. Yellow shaded areas indicate the local polarization voltage r]. For simplicity, the proton conductivity of catalyst layers is taken to be equal to the proton conductivity of the bulk membrane (otherwise the curve loses smoothness at the membrane interfaces). Note that the half-cell voltage loss is given by the value of the overpotential at the catalyst layer/membrane interface.

FIGURE 4.9 Polarization curve calculated with a CCL model that accounts for the full coupling between porous structure, liquid water accumulation, and performance. The dashed lines represent Hmiting scenarios corresponding to the ideally wetted state and the fuUy saturated state. Bistability occurs in the transition region. (Reprinted from Electrochim. Acta, 53(13), Liu, J., and Eikerling, M. Model of cathode catalyst layers for polymer electrolyte fuel cells The role of porous structure and water accumulation. 4435 1446. Copyright (2008), Elsevier. With permission.)... 

FI G U RE 4.21 Exact numerical (points) and analytical (Equation 4.189) (solid lines) polarization curves of the cathode catalyst layer with the finite rate of oxygen transport. The indicated parameter for the curves is the ratio D/Dref, where Dref = 1.37 10 cm s is the CCL oxygen diffusivity measured in Shen et al. (2011). The bottom solid line is the curve for infinitely fast oxygen transport in the CCL (Equation 4.141). 

Kulikovsky, A. A. 2011a. Polarization curve of a PEM fuel ceU with poor oxygen or proton transport in the cathode catalyst layer. 13, 1395-1399. 

FIGURE 10.19 Polarization curves with various weight percentages of H3P04-doped PBI ion-omer in the cathode catalyst layer, at 150 °C using dry H2/O2 feed [75]. 

If a cell is flooded in the cathode catalyst layer, fuel cell polarization curve generated with helox (21% O2 and 79% He) as the cathode gas will he ... 

One major goal of fuel-cell models is to match the experimental polarization curve for the operating conditions considered. The simplest approach is to treat the MEA as a reactive boundary between the anode and cathode sides. With increasing complexity, the two catalyst layers can be described separately as an effective boundary, a quasi-three-dimensional layer which is partially flooded with... 

The catalysts were tested as PEM fuel cell cathodic catalytic layers on a unit cell-test bench 50 cm Membrane-Electrode Assembhes (MEAs) were prepared by the decal method as described in reference [2]. The electrolyte was a Nafion membrane, and the anode a commercial anode made from Pt-doped carbon black (40 wt.%, TKK) deposited by Paxitech onto a carbon felt (0.6 mgpt cm mixed with Nafion ). The thickness of the cathode was kept constant by keeping constant the carbon mass in the catalytic layer. The Nafion /carbon mass ratio of the ink used to prepare the MEAs was fixed at 0.5. After a standardized start-up procedure, polarization curves, i.e. the t/ceii = f(/m) curves, were measured by setting the cell voltage at each desired value for 15 min, which... 

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