Multi-variable optimization of PEMFC cathodes using an agglomerate model

Abstract A comprehensive numerical framework for cathode electrode design is presented and applied to predict the catalyst layer and the gas diffusion layer parameters that lead to an optimal electrode performance at different operating conditions. The design and optimization framework couples an agglomerate cathode catalyst layer model to a numerical gradient-based optimization algorithm. The set of optimal parameters is obtained by solving a multi-variable optimization problem. The parameters are the catalyst layer platinum loading, platinum to carbon ratio, amount of electrolyte in the agglomerate and the gas diffusion layer porosity. The results show that the optimal catalyst layer composition and gas diffusion layer porosity depend on operating conditions. At low current densities, performance is mainly improved by increasing platinum loading to values above 1 mg cm −2 , moderate values of electrolyte volume fraction, 0.5, and low porosity, 0.1. At higher current densities, performance is improved by reducing the platinum loading to values below 0.35 mg cm −2 and increasing both electrolyte volume fraction, 0.55, and porosity 0.32. The underlying improvements due to the optimized compositions are analyzed in terms of the spatial distribution of the various overpotentials, and the effect of the agglomerate structure parameters (radius and electrolyte film) are investigated. The paper closes with a discussion of the optimized composition obtained in this study in the context of available experimental data. The analysis suggests that reducing the solid phase volume fraction inside the catalyst layer might lead to improved electrode performance.

[1]  Yong Woo Rho,et al.  Mass Transport Phenomena in Proton Exchange Membrane Fuel Cells Using O 2 / He , O 2 / Ar , and O 2 / N 2 Mixtures I . Experimental Analysis , 1994 .

[2]  Ralph E. White,et al.  Oxygen Reduction in a Proton Exchange Membrane Test Cell , 1989 .

[3]  P. Pickup,et al.  Ionic Conductivity of PEMFC Electrodes Effect of Nafion Loading , 2003 .

[4]  Timothy A. Davis,et al.  A column pre-ordering strategy for the unsymmetric-pattern multifrontal method , 2004, TOMS.

[5]  Titichai Navessin,et al.  A method for optimizing distributions of Nafion and Pt in cathode catalyst layers of PEM fuel cells , 2005 .

[6]  K. M. Chittajallu,et al.  Optimization of the cathode geometry in polymer electrolyte membrane (PEM) fuel cells , 2004 .

[7]  S. Litster,et al.  PEM fuel cell electrodes , 2004 .

[8]  P. Ekdunge,et al.  Modelling the PEM fuel cell cathode , 1997 .

[9]  Mark W. Verbrugge,et al.  A Mathematical Model of the Solid‐Polymer‐Electrolyte Fuel Cell , 1992 .

[10]  A. A. Kornyshev,et al.  Modelling the performance of the cathode catalyst layer of polymer electrolyte fuel cells , 1998 .

[11]  Jon G. Pharoah,et al.  On effective transport coefficients in PEM fuel cell electrodes: Anisotropy of the porous transport layers , 2006 .

[12]  Michael Eikerling,et al.  Functionally graded cathode catalyst layers for polymer electrolyte fuel cells - I. Theoretical modeling , 2004 .

[13]  Datong Song,et al.  Numerical optimization study of the catalyst layer of PEM fuel cell cathode , 2004 .

[14]  D. Luenberger.  Optimization by Vector Space Methods , 1968 .

[15]  G. Squadrito,et al.  Nafion content in the catalyst layer of polymer electrolyte fuel cells: effects on structure and performance , 2001 .

[16]  K. Oguro,et al.  Simulation of a polymer electrolyte fuel cell electrode , 1997 .

[17]  Ned Djilali,et al.  Three-dimensional computational analysis of transport phenomena in a PEM fuel cell—a parametric study , 2003 .

[18]  A. A. Kulikovsky,et al.  Modeling the Cathode Compartment of Polymer Electrolyte Fuel Cells: Dead and Active Reaction Zones , 1999 .

[19]  G. Lindbergh,et al.  Investigation of Mass-Transport Limitations in the Solid Polymer Fuel Cell Cathode I. Mathematical Model , 2002 .

[20]  Sanjeev Mukerjee,et al.  Effects of Nafion impregnation on performances of PEMFC electrodes , 1998 .

[21]  Timothy A. Davis,et al.  Algorithm 832: UMFPACK V4.3---an unsymmetric-pattern multifrontal method , 2004, TOMS.

[22]  Mica Grujicic,et al.  Cathode and interdigitated air distributor geometry optimization in polymer electrolyte membrane (PEM) fuel cells , 2004 .

[23]  Karren L. More,et al.  Porosimetry of MEAs Made by “Thin Film Decal” Method and Its Effect on Performance of PEFCs , 2004 .

[24]  A. Suleman,et al.  Numerical optimization of proton exchange membrane fuel cell cathodes , 2007 .

[25]  Xianguo Li,et al.  Composition and performance modelling of catalyst layer in a proton exchange membrane fuel cell , 1999 .

[26]  Edward L Cussler,et al.  Diffusion: Mass Transfer in Fluid Systems , 1984 .

[27]  Michael S. Eldred,et al.  DAKOTA, A Multilevel Parallel Object-Oriented Framework for Design Optimization, Parameter Estimation, Uncertainty Quantification, and Sensitivity Analysis Version 3.0 Reference Manual , 2001 .

[28]  Nathan P. Siegel,et al.  Single domain PEMFC model based on agglomerate catalyst geometry , 2003 .

[29]  Datong Song,et al.  Functionally Graded Cathode Catalyst Layers for Polymer Electrolyte Fuel Cells II. Experimental Study of the Effect of Nafion Distribution , 2005 .

[30]  Ned Djilali,et al.  Systematic parameter estimation for PEM fuel cell models , 2005 .

[31]  G. Sasikumar,et al.  Optimum Nafion content in PEM fuel cell electrodes , 2004 .

[32]  Hongtan Liu,et al.  A parametric study of the cathode catalyst layer of PEM fuel cells using a pseudo-homogeneous model , 2001 .

[33]  M. Verbrugge,et al.  Mathematical model of a gas diffusion electrode bonded to a polymer electrolyte , 1991 .

[34]  Hongtan Liu,et al.  Effects of the electrical resistances of the GDL in a PEM fuel cell , 2006 .

[35]  G. Lindbergh,et al.  Influence of the composition on the structure and electrochemical characteristics of the PEFC cathode , 2003 .

[36]  Kunal Karan.  Assessment of transport-limited catalyst utilization for engineering of ultra-low Pt loading polymer electrolyte fuel cell anode , 2007 .

[37]  Ned Djilali,et al.  THREE-DIMENSIONAL COMPUTATIONAL ANALYSIS OF TRANSPORT PHENOMENA IN A PEM FUEL CELL , 2002 .

[38]  Titichai Navessin,et al.  Numerical study of PEM fuel cell cathode with non-uniform catalyst layer , 2004 .

[39]  A. Weber,et al.  Modeling transport in polymer-electrolyte fuel cells. , 2004, Chemical reviews.

[40]  K. M. Chittajallu,et al.  Design and optimization of polymer electrolyte membrane (PEM) fuel cells , 2004 .

[41]  E. Passalacqua,et al.  Influence of Nafion loading in the catalyst layer of gas-diffusion electrodes for PEFC , 1999 .