Yong Liu is a professor at the College of Materials Science and Engineering, Beijing University of Chemical Technology, China. His research focuses on the preparation and application of polymer and nanocomposite materials.Dr. Mohideen Meerasahib Mohamedazeem is a Materials Science expert with a deep focus on sustainable energy solutions. He received an International Scientist funding award from the Beijing Natural Science Foundation, where he will lead a project from 2024 to 2026.

• About the Authors xiiiPreface xvAcknowledgment xvii1 Introduction to Proton Exchange Membrane Fuel Cells 11.1 Overview of Proton Exchange Membrane Fuel Cells Technology 11.1.1 Brief History and Development of Proton Exchange Membrane Fuel Cell 11.1.2 Need for H2 -Powered Fuel Cell Technology in Today’s World 21.2 Key Components of Proton Exchange Membrane Fuel Cell 61.2.1 Catalyst Layer 61.2.2 Gas Diffusion Layer 91.2.3 Proton Exchange Membrane 101.2.3.1 Proton Transport Mechanisms 111.2.3.2 Classification of PEM 14References 162 Classification of Catalyst for Proton Exchange Membrane Fuel Cell 232.1 State-of-the-Art Electrocatalysts 232.1.1 Pt-Alloy Electrocatalysts 232.1.2 Carbon-Supported Transition Metal Catalysts (M-N-C) 252.1.3 MXene-Based ORR Catalysts 262.1.4 Metal-Organic Framework Electrocatalysts 272.1.5 Carbon-Based Metal-Free Electrocatalyst 282.2 Fabrication of Catalyst Layers (CL) in Proton Exchange Membrane Fuel Cell 292.2.1 GDE Membrane Electrode 292.2.2 Catalyst-Coated Membrane Electrode 312.2.3 Ordered Membrane Electrode 322.3 Conclusion 33References 333 Electrospun Catalyst Layer for Proton Exchange Membrane Fuel Cell 393.1 Introduction 393.2 Materials Preparation 393.2.1 Preparation of Nanofiber Catalyst Layers 393.3 Preparation and Electrochemical Characterization 413.3.1 Preparation of Single Cell 413.3.2 Polarization Curve Testing (V–I) 423.3.3 Cyclic Voltammetry Testing 423.3.4 Linear Sweep Voltammetry Testing 433.3.5 Electrochemical Impedance Spectroscopy Testing 433.4 Results and Discussion 443.4.1 Polarization Curve (V–I) of Preconditioning Process 443.4.2 Electrochemical Impedance Spectroscopy of Preconditioning Process 463.4.3 Impedance Fitting Data of Preconditioning Process 483.4.4 Electrochemically Active Surface Area of Preconditioning Process 493.4.5 Exchange Current Density of Preconditioning Process 493.4.6 Mechanism of Activation Process 513.5 Conclusion 53References 544 Analysis of Nanofiber Catalyst Layers Performance Under Various Temperature and Humidity Conditions 574.1 Introduction 574.2 Materials Preparation 574.3 Result and Discussion 574.3.1 Polarization Curves (V–I) at Constant Temperature and Different Humidity Levels 574.3.2 Polarization Curves (V–I) at Different Temperatures and Constant Humidity 594.3.3 Polarization Curves and Loss Separation at Different Temperatures and Humidity 614.4 Conclusion 63References 645 The Role and Performance of Gas Diffusion Layers in Proton Exchange Membrane Fuel Cell 675.1 Introduction 675.2 Research on Gas Diffusion Layer and Water/Gas Transport Mechanisms 685.2.1 Research on Microporous Layer 725.3 Conclusion 75References 756 Preparation of Gradient Gas Diffusion Layer Process and Their Performance in Fuel Cell 796.1 Introduction 796.2 Materials Preparation 796.2.1 Effect of Ultrasonic Time on Gas Diffusion Layer Preparation 796.2.2 Effect of Polytetrafluoroethylene Addition Sequence 806.2.3 Investigation of Ethanol Content and Heating Plate Temperature 806.2.4 Preparation and Testing of Gradient Gas Diffusion Layer 806.3 Results and Discussion 816.3.1 Hydrophobicity 816.3.2 Water Permeability and Conductivity 816.3.3 Pore Size Distribution 836.3.4 Pore Volume Distribution 846.3.5 Surface Roughness 856.3.6 Surface Morphology 866.3.7 Polarization Curve and Power Density 886.3.8 Electrochemical Impedance Spectroscopy Test 916.4 Conclusion 92References 927 Impact of Optimizing the Thickness Direction of Gradient Gas Diffusion Layer on Water-Gas Management Capability of the Fuel Cell 957.1 Introduction 957.2 Materials Preparation 957.2.1 Preparation Process of Gradient Gas Diffusion Layers 957.3 Results and Discussion 967.3.1 Physical Characterizations 977.3.2 Analysis of Polarization Curve (I–V) 987.3.3 Analysis of Power Density 1007.3.4 Water Transport Mechanism 1017.3.5 Comparison of Capillary Pressure Differences in Gas Diffusion Layers with Varying Thicknesses 1017.3.6 Electrochemical Impedance Spectroscopy 1037.3.7 Polarization Curve Reproducibility 1047.4 Conclusion 104References 1058 Study on the Effect of Gradient Hydrophobic Treatment of Gas Diffusion Layer on Water Management Performance in Fuel Cells 1078.1 Introduction 1078.2 Materials Preparation 1078.3 Results and Discussion 1088.3.1 Analysis of Polarization Curve (I–V) 1088.3.2 Analysis of Power Density 1098.3.3 Analysis of Electrochemical Impedance Spectroscopy 1108.3.4 Analysis of Physical Performance 1108.3.5 Verifying the Effect of Gradient Hydrophobic Gas Diffusion Layers with Different Polytetrafluoroethylene/Carbon Black Ratios in Fuel Cells 1128.3.5.1 Analysis of Polarization Curve 1128.3.5.2 Analysis of Power Density 1138.3.5.3 Analysis of Electrochemical Impedance Test Results 1148.4 Comparison of Membrane Electrodes 1148.5 Conclusion 115References 1159 Fundamentals of Proton Exchange Membranes 1179.1 Introduction 1179.1.1 Partially Fluorinated Proton Exchange Membranes 1189.1.2 Fluorine-Free Proton Exchange Membranes 1199.1.3 Sulfonated Polysulfone Proton Exchange Membranes 1209.1.4 Sulfonated Polyaryletherketone Proton Exchange Membranes 1219.1.5 Sulfonated Polyimide Proton Exchange Membranes 1249.2 Conclusion 125References 12610 Design of Proton Exchange Membrane 13110.1 Introduction 13110.2 Design of Molecular Structure 13210.3 Physical and Chemical Cross-Linking Modification 13410.4 Enhancing Stability and Performance Through Chemical Cross-Linking 13610.5 Modulating the Structure of Ordered Microporous Materials 14110.6 Construction of Novel Proton Transport Channels 14510.7 Conclusion 147References 14811 Highly Sulfonated Poly(Ether Ether Ketone) Nanofibers Constructed Plasmonic Transport Channels 15511.1 Introduction 15511.2 Materials Preparation 15611.2.1 Preparation of Sulfonated Poly(Ether Ether Ketone) with Different Degrees of Sulfonation 15611.2.2 Substitution of Counteracting Ions 15611.2.3 Preparation of Sulfonated Poly(Ether Ether Ketone) Nanofibers 15711.2.4 Preparation of Nanofiber Composite Membranes 15711.2.5 Thermal Cross-Linking of Nanofiber Composite Membranes 15811.3 Results and Discussion 15811.3.1 Preparation of Sulfonated Poly(Ether Ether Ketone) and Characterization of Nanofibers 15811.3.2 Cross-Sectional Morphology of Fiber Composite Membranes 16011.3.3 Chemical Structure Characterization of Composite Membranes 16211.3.4 Mechanical Properties and Thermal Stability 16311.3.5 Water Absorption and Solubility 16411.3.6 Membrane Proton Conductivity 16511.3.7 Antioxidant Stability 16611.3.8 Fuel Cell Performance 16811.4 Conclusion 169References 17012 Polydopamine-Modified Halloysite Nanotube/Sulfonated Poly(Ether Ether Ketone) Cross-Linked Composite Membrane 17312.1 Introduction 17312.2 Materials Preparation 17512.2.1 Polydopamine Coating of Halloysite Nanotubes 17512.2.2 Sulfonation of Poly(Ether Ether Ketone) 17512.2.3 Preparation of Thermally Cross-Linked Composite Membranes 17612.3 Results and Discussion 17612.3.1 Characterization of Dopamine-Modified Halloysite Nanotubes 17612.3.2 Discussion on the Sulfonation Process of Poly(Ether Ether Ketone) 17912.3.3 Morphological Characterization of Composite Membranes 18012.3.4 Chemical and Physical Properties of the Composite Membranes 18012.3.5 Ion Exchange Capacities, Water Absorption Rate, and Swelling Rate 18312.3.6 Proton Conductivity 18612.3.7 Fuel Cell Performance 18912.4 Conclusion 190References 19013 Construction of Ordered Proton Transport Channels with Phosphotungstic Acid Modified Magnetic Nanoparticles 19313.1 Introduction 19313.2 Materials Preparation 19413.2.1 Preparation of Magnetic Nanoparticles 19413.2.2 Preparation of Phosphotungstic Acid-Loaded Magnetic Nanoparticles 19413.2.3 Sulfonation of Poly(Ether Ether Ketone) and Preparation of Composite Membranes 19513.2.4 Preparation of Composite Membranes 19513.3 Result and Discussion 19613.3.1 Preparation and Characterization of DMNPs@HPW 19613.3.2 Morphology of Composite Membrane Sections 20113.3.3 Proton Conduction Pathways and Particle Distribution 20213.3.4 Characterization of Composite Membranes X-ray Diffraction 20213.3.5 Mechanical Properties of Composite Membranes 20413.3.6 Ion Exchange Capacities, Water Uptake, and Swelling Ratio 20513.3.7 Proton Conductivity of the Membranes 20713.3.8 Fuel Cell Performance 21013.4 Conclusion 211References 21214 Chemical Covalent Bonding of Silicotungstic Acid Proton Exchange Membrane 21514.1 Introduction 21514.2 Materials Preparation 21614.2.1 Synthesis of 4-Phenoxyphenyl Phosphoric Acid 21614.2.2 Synthesis of 4-Phenoxyphenyl Diethylphosphoric Acid Ester 21614.2.3 Hydrolysis to Prepare 4-Phenoxyphenyl Phosphoric Acid 21714.2.4 Preparation of Deficient Silicotungstic Acid Potassium 21714.2.5 Preparation of POP-SiWA 21714.2.6 Sulfonated Poly(Ether Ether Ketone)-Immobilized POP-SiWA 21814.3 Results and Discussion 22014.3.1 Characterization of POP-SiWA 22014.3.2 Discussion on Thermal Cross-Linking and Grafting 22214.3.3 Characterization of Cross-Linked Grafted Membranes 23014.3.4 Ion Exchange Capacities, Water Uptake, and Swelling Ratio 23214.3.5 Anti–Free Radical Oxidation Properties 23414.3.6 Proton Conductivity 23514.3.7 Fuel Cell Performance 23714.4 Conclusion 239References 239Index 241