Modern Aspects of Electrochemistry No. 40

by White, Ralph E.; Vayenas, C. G.; Gamboa-Aldeco, Maria E.

• ISBN13: 9780387460994
• ISBN10: 0387460993
• Edition: 1st
• Format: Hardcover
• Copyright: 2007-02-23
• Publisher: Springer Verlag

Summary

This volume in the acclaimed series Modern Aspects of Electrochemistry starts with a dedication to the late Professor Brian Conway who for 50 years helped to guide this series to its current prominence. The remainder of the volume is then devoted to the following topics: PEM fuel cells; The use of graphs in electrochemical reaction newtworks; nanomaterials in Lithium-ion batteries; direct methanolf fuel cells (two chapters); fuel cell catalyst layers.

Table of Contents

Pem Fuel Cell Bipolar Plates
Introduction	p. 1
NAFION MEA Based Bipolar Plate Problems	p. 2
Polybenzimidazole/H[subscript 3]PO[subscript 4]	p. 3
Definition	p. 3
Separator Plate	p. 4
Flow Field	p. 5
Port and Port Bridges	p. 6
Seals	p. 7
Frame	p. 8
Bipolar Plate Features	p. 8
Tolerances	p. 9
Thermal Management	p. 9
Electrical Conduction	p. 10
Water Management	p. 11
Low Cost	p. 13
Stable, Free from Corrosion Products	p. 13
Galvanic Corrosion	p. 13
Materials and Processes	p. 15
Comparison of Carbon and Metal	p. 15
Operational	p. 16
Forming Cost	p. 16
Carbon	p. 18
Molded Graphite	p. 18
Paper	p. 19
Stamped Exfoliated Graphite (Grafoil, Graflex)	p. 19
Metal	p. 19
Forming Metal Bipolar Plates	p. 20
Intrinsically Corrosion Resistant Metals	p. 21
Direct Coatings	p. 21
Conductive Polymer Grafting	p. 24
References	p. 33
Basic Applications of the Analysis of Variance and Covariance in Electrochemical Science and Engineering
Introduction	p. 37
Basic Principles and Notions	p. 38
ANOVA: One-way Classification	p. 40
Completely Randomized Experiment (CRE)	p. 42
Randomized Block Experiment (RBE)	p. 42
Example 1: A Historical Perspective of Caustic Soda Production	p. 43
Example 2: Metallic Corrosion	p. 45
ANOVA: Two-Way Classification	p. 46
Null and Alternative Hypotheses	p. 46
Illustration of Two-Way Classification: Specific Energy Requirement for an Electrolytic Process	p. 47
ANOVA: Three-Way Classifications	p. 49
ANOVA: Latin Squares (LS)	p. 51
Applications of the Analysis of Covariance (ANCOVA)	p. 53
ANCOVA with Velocity as Single Concomitant Variable	p. 53
Pattern A(CRE)	p. 53
Pattern B(RBE)	p. 56
ANCOVA with Velocity and Pressure Drop Acting as Two Concomitant Variables	p. 58
Two Covariate-Based ANCOVA of Product Yields in a Batch and in a Flow Electrolyzer	p. 58
Covariance Analysis for a Two-Factor, Single Cofactor CRE	p. 60
Miscellaneous Topics	p. 62
Estimation of the Type II Error in ANOVA	p. 62
Hierarchical Classification	p. 64
ANOVA-Related Random Effects	p. 66
Introductory Concepts of Contrasts Analysis	p. 69
Final Remarks	p. 71
Acknowledgments	p. 72
List of Principal Symbols	p. 72
References	p. 73
Nanomaterials in Li-Ion Battery Electrode Design
Introduction	p. 75
Templates Used	p. 78
Track-Etch Membranes	p. 78
Alumina Membranes	p. 80
Other Templates	p. 81
Nanostructured Cathodic Electrode Materials	p. 83
Electrode Fabrication	p. 84
Nanostructured Electrode	p. 84
Control Electrodes	p. 85
Structural Investigations	p. 86
Electrochemical Characterization	p. 87
Cyclic Voltammetry	p. 87
Rate Capabilities	p. 89
Nanostructured Anodic Electrodes	p. 91
Electrode Fabrication	p. 92
Nanostructured Electrodes	p. 92
Control Electrodes	p. 92
Structural Investigations	p. 93
Electrochemical Investigations	p. 95
Nanoelectrode Applications	p. 97
Low-Temperature Performance	p. 97
Electrode Fabrication	p. 97
Strategy	p. 98
Electrochemical Results	p. 99
Electronic Conductivity	p. 101
Cycle Life	p. 102
Variations on a Synthetic Theme	p. 102
Nanocomposite of LiFePO[subscript 4]/Carbon	p. 102
Improving Volumetric Capacity	p. 109
Carbon Honeycomb	p. 117
Preparation of Honeycomb Carbon	p. 118
Electrochemical Characterization	p. 121
Conclusions	p. 123
Acknowledgements	p. 123
References	p. 124
Direct Methanol Fuel Cells: Fundamentals, Problems and Perspectives
Introduction	p. 127
Operating Principle of the SPE-DMFC	p. 128
Electrode Reaction Mechanisms in SPE-DMFCs	p. 132
Anodic Oxidation of Methanol	p. 132
Cathodic Reduction of Oxygen	p. 139
Materials for SPE-DMFCS	p. 140
Catalyst Materials	p. 140
Anode Catalysts	p. 140
Oxygen Reduction Catalysts	p. 149
Membrane Materials	p. 156
Direct Methanol Fuel Cell Performance	p. 163
DMFC Stack Performance	p. 175
Alternative Catalysts and Membranes in the DMFC	p. 178
Alkaline Conducting Membrane and Alternative Oxidants	p. 183
Conventional vs. Mixed-Reactant SPE-DMFCs	p. 185
Mathematical Modelling of the DMFC	p. 192
Methanol Oxidation	p. 195
Empirical Models for Cell Voltage Behaviour	p. 198
Membrane Transport	p. 202
Effect of Methanol Crossover on Fuel Cell Performance	p. 204
Mass Transport and Gas Evolution	p. 205
DMFC Electrode Modelling	p. 209
Cell Models	p. 210
Single Phase Flow	p. 212
Two-and Three-Dimensional Modelling	p. 213
Dynamics and Modelling	p. 215
Stack Hydraulic and Thermal Models	p. 215
Conclusions	p. 216
List of Symbols	p. 217
References	p. 218
Review of Direct Methanol Fuel Cells
Introduction	p. 229
Anode Kinetics	p. 232
Reaction Mechanism	p. 232
Methanol Oxidation Catalysts	p. 233
Platinum and Platinum Catalyst Structure	p. 233
Platinum and Platinum Alloy Catalyst Performance	p. 240
Oxygen Reduction Reaction Catalysts	p. 247
High Temperature Membranes	p. 248
Methanol Crossover	p. 253
Magnitude of Crossover	p. 253
Effect of CO[subscript 2] Crossover	p. 258
Mixed-Potential Effects	p. 260
Novel Membranes to Reduce Methanol Crossover	p. 261
DMFC Modeling Review	p. 264
One-Dimensional Models	p. 265
Two-Dimensional and Three-Dimensional Models	p. 273
Summary	p. 278
References	p. 280
Direct Numerical Simulation of Polymer Electrolyte Fuel Cell Catalyst Layers
Introduction	p. 285
Direct Numerical Simulation (DNS) Approach	p. 288
Advantages and Objectives of the DNS Approach	p. 289
DNS Model - Idealized 2-D Microstructure	p. 290
Three-Dimensional Regular Microstructure	p. 293
Results and Discussion	p. 299
2-D Model: Kinetics- vs. Transport-Limited Regimes	p. 299
Comparison of the Polarization Curves between 2-D and 3-D Simulations	p. 304
Three-Dimensional Random Microstructure	p. 305
Random Structure	p. 306
Structural Analysis and Identification	p. 307
Governing Equations	p. 311
Boundary Conditions	p. 314
Results and Discussion	p. 316
DNS Model - Water Transport	p. 320
Water Transport Mechanism	p. 321
Mathematical Description	p. 323
Results and Discussion	p. 327
Inlet-Air Humidity Effect	p. 327
Water Crossover Effect	p. 330
Optimization of Catalyst Layer Compositions	p. 331
3-D Correlated Microstructure	p. 333
Stochastic Generation Method	p. 333
Governing Equations, Boundary Conditions and Numerical Procedure	p. 334
Results and Discussion	p. 337
Conclusions	p. 340
Acknowledgements	p. 340
References	p. 341
Index	p. 343
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