Polarization Curve

2011 ◽  
pp. 35-56
Keyword(s):  
Author(s):  
C. C. Kuo ◽  
W. E. Lear ◽  
J. H. Fletcher ◽  
O. D. Crisalle

A constructive critique and a suite of proposed improvements for a recent one-dimensional semianalytical model of a direct methanol fuel cell are presented for the purpose of improving the predictive ability of the modeling approach. The model produces a polarization curve for a fuel cell system comprised of a single membrane-electrode assembly, based on a semianalytical one-dimensional solution of the steady-state methanol concentration profile across relevant layers of the membrane electrode assembly. The first improvement proposed is a more precise numerical solution method for an implicit equation that describes the overall current density, leading to better convergence properties. A second improvement is a new technique for identifying the maximum achievable current density, an important piece of information necessary to avoid divergence of the implicit-equation solver. Third, a modeling improvement is introduced through the adoption of a linear ion-conductivity model that enhances the ability to better match experimental polarization-curve data at high current densities. Fourth, a systematic method is advanced for extracting anodic and cathodic transfer-coefficient parameters from experimental data via a least-squares regression procedure, eliminating a potentially significant parameter estimation error. Finally, this study determines that the methanol concentration boundary condition imposed on the membrane side of the membrane-cathode interface plays a critical role in the model’s ability to predict the limiting current density. Furthermore, the study argues for the need to carry out additional experimental work to identify more meaningful boundary concentration values realized by the cell.


Author(s):  
Gabriel Ybarra ◽  
Carlos Moina ◽  
María Inés Florit ◽  
Dionisio Posadas

<p class="PaperAbstract"><span lang="EN-US">In this work, the mediated reduction and oxidation of Fe(CN)<sub>6</sub><sup>3-/4-</sup> and Fe<sup>3+ </sup>in poly(o-aminophenol) coated electrodes is analyzed by means of diagnosis diagram based on the features of steady state current-potential curves. This analysis allows to identify the current determining process and to reproduce the experimental characteristics of the polarization curve from the relevant kinetic and thermodynamical parameters with a minimum amount of experimental measurements. </span></p>


2020 ◽  
Vol 2020 (1) ◽  
pp. 000150-000155
Author(s):  
Raihei Ikumoto ◽  
Yuki Itakura ◽  
Shinji Tachibana ◽  
Hisamitsu Yamamoto

Abstract Cu plating bath for high-speed electrodeposition of Cu pillar was designed in consideration of a flat top morphology of pillar and a pillar height uniformity. An ideal polarization curve was assumed for the flat top morphology. To obtain the ideal polarization curve, an effect of organic additive concentration and solution agitation on the polarization curve were investigated. The basic bath components were optimized considering a Wagner number to improve pillar height uniformity. To confirm the pillar top morphology and the pillar height uniformity, a 300 mm diameter wafer was plated with Cu at 20 A/dm2. As a result, improved pillar top morphology and pillar height uniformity were obtained. The optimized plating bath was applied to the plating of large-size panel of 415 × 510 mm.


1974 ◽  
Vol 187 ◽  
pp. L117 ◽  
Author(s):  
G. E. Mavko ◽  
D. S. Hayes ◽  
J. M. Greenberg ◽  
W. A. Hiltner

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