Note: Intro -- Preface -- Contents -- List of Contributors, MAE 49 -- Modern Aspects of Electrochemistry -- 1 Durability of PEM Fuel Cell Membranes -- 1 Summary -- 2 Review of PEM Fuel Cell Degradation Phenomena and Mechanisms -- 3 Membrane Degradation -- 3.1. Stress in Membrane and MEAs -- 3.2. Mechanical Characterization of Membranes -- 3.3. Chemical Degradation Processes -- 3.4. Mechanical Degradation Processes -- 3.5. Interactions of Chemical and Mechanical Degradation -- 4 Accelerated Testing and Life Prediction -- 4.1. Accelerated Degradation Testing and Degradation Metrics -- 4.2. Progressive Degradation Model of Combined Effects -- 5 Mitigation -- Acknowledgments -- References -- 2 Modeling of Membrane-Electrode-Assembly Degradation in Proton-Exchange-Membrane Fuel Cells -- Local H2 Starvation and Start--Stop Induced Carbon-Support Corrosion -- 1 Introduction -- 2 Kinetic Model -- 2.1. Electrode Kinetics -- 2.2. Local H2 Starvation Model -- 2.3. Start--Stop Model -- 3 Coupled Kinetic and Transport Model -- 3.1. Model Description -- 3.2. Local H2 Starvation Simulation -- 3.3. Start--Stop Simulation -- 4 Pseudo-Capacitance Model -- 4.1. Mechanism Description -- 4.2. Model Description -- 4.3. The Pseudo-capacitive Effect -- 5 Summary and Outlook -- Acknowledgments -- List of Symbols -- References -- 3 Cold Start of Polymer Electrolyte Fuel Cells -- 1 Introduction -- 2 Equilibrium Purge Cold Start -- 2.1. Equilibrium Purge -- 2.2. Isothermal Cold Start -- 2.3. Proton Conductivity at Low Temperature -- 2.4. Effects of Key Parameters -- 2.4.1. Initial Membrane Water Content -- 2.4.2. Startup Current Density -- 2.4.3. Startup Temperature -- 2.5. ORR Kinetics at Low Temperatures -- 2.6. Short-Purge Cold Start -- 3 Water Removal During Gas Purge -- 3.1. Introduction -- 3.2. Purge Curve -- 3.3. Two Characteristic Parameters for Water Removal. , 3.4. Stages of Purge -- 3.5. Effect of Key Parameters -- 3.5.1. Purge Cell Temperature -- 3.5.2. Purge Gas Flow Rate -- 3.5.3. Matching Two Parameters -- 3.6. HFR Relaxation -- 4 Concluding Remarks -- References -- 4 Species, Temperature, and Current Distribution Mapping in Polymer Electrolyte Membrane Fuel Cells -- 1 Introduction -- 2 Species Distribution Mapping -- 2.1. Species and Properties of Interest -- 2.1.1. Hydrogen -- 2.1.2. Oxygen -- 2.1.3. Water -- 2.1.4. Contaminants and Diluents -- 2.1.5. Pressure Drop -- 2.1.6. Flow Distribution -- 2.2. Methodology and Results -- 2.2.1. Pressure Drop Measurement -- 2.2.2. Gas Composition Analysis -- 2.2.3. Neutron Imaging -- 2.2.4. Magnetic Resonance Imaging -- 2.2.5. X-ray Imaging -- 2.2.6. Optically Transparent Fuel Cells -- 2.2.7. Embedded Sensors -- 2.2.8. Other Methods -- 2.3. Design Implications -- 3 Temperature Distribution Mapping -- 3.1. Methodology and Results -- 3.1.1. IR Transparent Fuel Cells -- 3.1.2. Embedded Sensors -- 3.2. Design Implications -- 4 Current Distribution Mapping -- 4.1. Methodology and Results -- 4.1.1. Partial MEA -- 4.1.2. Segmented Cells -- 4.1.3. Other Methods -- 4.2. Design Implications -- 5 Concluding Remarks -- References -- 5 High-Resolution Neutron Radiography Analysis of Proton Exchange Membrane Fuel Cells -- 1 Introduction -- 2 Neutron Radiography Facility Layout And Detectors -- 2.1. Neutron Sources and Radiography Beamlines -- 2.2. Neutron Imaging Detectors -- 3 Water Metrology with Neutron Radiography -- 3.1. Neutron Attenuation Coefficient of Water, 0 w -- 3.2. Sources of Uncertainties in Neutron Radiography -- 3.2.1. Counting Statistics -- 3.2.2. Beam Hardening -- 3.2.3. Background Subtraction -- 3.2.4. Changes in the Total Neutron Scattering from Water Absorbed in the Membrane -- 3.2.5. Image Spatial Resolution. , 4 Recent In Situ High-Resolution Neutron Radiography Experiments of PEMFCs -- 4.1. Proof-of-Principle Experiments -- 4.2. In Situ, Steady-State Through-Plane Water Content -- 4.3. Dynamic Through-Plane Mass Transport Measurements -- 5 Conclusions -- Acknowledgments -- References -- 6 Magnetic Resonance Imaging and Tunable Diode Laser Absorption Spectroscopy for In-Situ Water Diagnostics in Polymer Electrolyte Membrane Fuel Cells -- 1 Introduction -- 2 Magnetic Resonance Imaging (MRI): As a Diagnostic Tool for In-Situ Visualization of Water Content Distribution in PEMFC s -- 2.1. Basic Principle of MRI -- 2.2. MRI System Hardware for PEMFC Visualization -- 2.3. MRI Signal Calibration for Water Content in PEM -- 2.4. In Situ Visualization of Water in PEMFC Using MRI -- 3 Tunable Diode Laser Absorption Spectroscopy (TDLAS): As a Diagnostic Tool for In-Situ Detection of Water Vapor Concentration in PEMFC s -- 3.1. Basic Principle of TDLAS -- 3.2. TDLAS System Hardware for Water Vapor Measurement -- 3.3. TDLAS Signal Calibration for Measurement of Water Vapor Concentration -- 3.4. In Situ Measurement of Water Vapor in PEMFC Using TDLAS -- 4 Summary -- References -- 7 Characterization of the Capillary Properties of Gas Diffusion Media -- 1 Introduction -- 1.1. Motivation -- 2 Basic Considerations -- 3 Measurement of Capillary Pressure Curves -- 4 Interpretation of Capillary Pressure Curves -- 4.1. Capillary Pressure Hysteresis -- 4.2. Effect of Hydrophobic Coating -- 4.3. Effect of Compression -- 4.4. Water Breakthrough Condition -- 4.5. Finite-Size Effects -- 4.6. Effect of Microporous Layer -- 5 Conclusion and Outlook -- References -- 8 Mesoscopic Modeling of Two-Phase Transport in Polymer Electrolyte Fuel Cells -- 1 Introduction -- 2 Model Description -- 2.1. Stochastic Microstructure Reconstruction Model. , 2.1.1. Catalyst Layer Structure Generation -- 2.1.2. Gas Diffusion Layer Structure Generation -- 2.2. Lattice Boltzmann Model -- 2.2.1. Two-phase LB Model Description -- 3 Two-Phase Simulation -- 3.1. Two-phase Transport Mechanism -- 3.2. Two-phase Numerical Experiments and Setup -- 4 Two-Phase Behavior and Flooding Dynamics -- 4.1. Structure-Wettability Influence -- 4.2. Effect of GDL Compression -- 4.3. Evaluation of Two-Phase Relations -- 4.4. Effect of Liquid Water on Performance -- 5 Summary and Outlook -- Acknowledgments -- References -- 9 Atomistic Modeling in Study of Polymer Electrolyte Fuel Cells -- A Review -- 1 Introduction -- 2 Fundamentals of Atomistic Modeling -- 2.1. Ab Initio Modeling of Materials -- 2.1.1. Adiabatic Approximation -- 2.1.2. Hatree--Fock Approximation and Single Electron Hamiltonian -- 2.1.3. Density Function Theory -- 2.1.4. Ab Initio Quantum Chemistry Computation -- 2.1.5. Ab Initio Molecular Dynamics -- 2.2. Classical Molecular Dynamic Modeling -- 2.3. Monte Carlo Modeling -- 2.3.1. The Metropolis Algorithm -- 2.3.2. Kinetic Monte Carlo Modeling -- 2.4. Advancement of MD Methods -- 2.4.1. Empirical Valence Bond Models -- 2.4.2. MD Modeling with Reactive Force Field -- 2.4.3. Methods for Accelerating Molecular Dynamics Simulations -- 3 Modeling of Oxygen Electroreduction Reaction Catalysts -- 3.1. The Interface Structure -- 3.1.1. Ab Initio Modeling of Interface Structure in Aqueous Solutions -- 3.1.2. MD Modeling of Interface Structure on Catalysts in Aqueous Solution -- 3.1.3. MD Modeling of Interface Structure of Polymer Electrolyte/Catalysts Interface -- 3.2. Chemsorption on Catalysts -- 3.2.1. Bond Strength of Adsorbed Oxygen Atom -- 3.2.2. Adsorption Process on Transition Metals -- 3.2.3. On Bimetallic Alloys -- 3.3. Oxygen Electroreduction Reaction with an Emphasis on Charge Transfer at Metal/Water Interface. , 4 Modeling of Oxidation of Carbon Monoxide and Methanol -- 4.1. ''Vapor Phase'' Model -- 4.2. Realistic ''Liquid Phase'' Model -- 5 Modeling of Transport Processes in Nafion Polymer Electrolytes -- 5.1. Theoretical Views of Proton Transport in Aqueous Systems and in Hydrated Nafion Membranes -- 5.1.1. In Aqueous Solution -- 5.1.2. In Hydrated Membrane (Nafion) -- 5.2. Ab Initio Models -- 5.3. Classic MD Models -- 5.4. Empirical Valence Bond and ReaXFF Models -- 6 Summarizing Remarks -- Acknowledgment -- Reference -- Index.