1st Edition

Micro & Nano-Engineering of Fuel Cells

Edited By Dennis Y.C. Leung, Jin Xuan Copyright 2015
    338 Pages
    by CRC Press

    338 Pages
    by CRC Press

    Fuel cells are clean and efficient energy conversion devices expected to be the next generation power source. During more than 17 decades of research and development, various types of fuel cells have been developed with a view to meet the different energy demands and application requirements. Scientists have devoted a great deal of time and effort to the development and commercialization of fuel cells important for our daily lives. However, abundant issues, ranging from mechanistic study to system integration, still need to be figured out before massive applications can be used. Miniaturization is one of the main bottlenecks for the advancement and further development of fuel cells. Thus, research on miniaturization of fuel cells as well as understanding the micro and nano structural effect on fuel cell performance are necessary and of great interest to solve the challenges ahead.

    In this book, internationally acclaimed experts illustrate how micro & nano engineering technology can be applied as a way of removing the restrictions presently faced by fuel cells both technically and theoretically. Through the twelve well designed chapters, major issues related to the miniaturization of different types of fuel cells are addressed. Theory focusing on micro and nano scale mechanics are outlined to better optimize the performance of fuel cells from laboratory scale to industrial scale. This book will be a good reference to those scientists and researchers interested in developing fuel cells through micro and nano scale engineering.

    About the book series
    Editorial board
    List of contributors
    About the editors

    1. Pore-scale water transport investigation for polymer electrolyte membrane (PEM) fuel cells
    Takemi Chikahisa & Yutaka Tabe
    1.1 Introduction
    1.2 Basics of cell performance and water management
    1.3 Water transport in the cell channels
    1.3.1 Channel types
    1.3.2 Observation of water production, temperatures, and current density distributions
    1.3.3 Characteristics of porous separators
    1.4 Water transport in gas diffusion layers
    1.4.1 Water transport with different anisotropic fiber directions of the GDL
    1.4.2 Water transport simulation in GDLs with different wettability gradients
    1.5 Water transport through micro-porous layers (MPL)
    1.5.1 Effect of the MPL on the cell performance
    1.5.2 Observation of the water distribution in the cell
    1.5.3 Analysis of water transport through MPL
    1.5.4 Mechanism for improving cell performance with an MPL
    1.6 Transport phenomena and reactions in the catalyst layers
    1.6.1 Introduction
    1.6.2 Analysis model and formulation
    1.6.3 Results of analysis and major parameters in CL affecting performance
    1.7 Water transport in cold starts
    1.7.1 Cold start characteristics and the effect of the start-up temperature
    1.7.2 Observation of ice distribution and evaluation of the freezing mechanism
    1.7.3 Strategies to improve cold start performance
    1.8 Summary

    2. Reconstruction of PEM fuel cell electrodes with micro- and nano-structures
    Ulises Cano-Castillo & Romeli Barbosa-Pool
    2.1 Introduction
    2.1.1 The technology: complex operational features required Nano-technology to the rescue? Challenges: technical and economic goals still remain
    2.2 Catalyst layers’ structure: a reason to reconstruct
    2.2.1 Heterogeneous materials
    2.2.2 First steps for the reconstruction of catalyst layers Structural features matter Scaling – a matter of perspectives
    2.2.3 Stochastic reconstruction – scaling method Statistical signatures
    2.2.4 Let’s reconstruct Features of reconstructed structures Effective ohmic conductivity CL voltage distribution, electric and ionic transport coefficients
    2.2.5 Structural reconstruction: annealing route Image processing for statistical realistic information Structural reconstruction – annealing method Statistical functions – two scales Effective electric resistivity simulation from a reconstructed structure
    2.3 New material support and new catalyst approaches
    2.3.1 Carbon nanotubes “decorated” with platinum Substantial differences for CNT structures CNT considerations when inputting component properties
    2.3.2 Core-shell-based catalyzers General considerations for reconstruction
    2.4 Concluding remarks

    3. Multi-scale model techniques for PEMFC catalyst layers
    Yu Xiao, Jinliang Yuan & Ming Hou
    3.1 Introduction
    3.1.1 Physical and chemical processes at different length and time scales
    3.1.2 Needs for multi-scale study in PEMFCs
    3.2 Models and simulation methods at different scales
    3.2.1 Atomistic scale models at the catalyst surface Dissociation and adsorption processes on the Pt surface Reaction thermodynamics
    3.2.2 Modeling methods at nano-/micro-scales Molecular dynamics modeling method Monte Carlo methods
    3.2.3 Models at meso-scales Dissipative particle dynamics (DPD) Lattice Boltzmann method (LBM) Smoothed particle hydrodynamics (SPH) method
    3.2.4 Simulation methods at macro-scales
    3.3 Multi-scale model integration technique
    3.3.1 Integration methods on atomistical scale to nano-scale
    3.3.2 Microscopic CL structure simulation
    3.3.3 Analyses of predicted CLs microscopic structures Microscopic parameters evaluation Primary pore structure analysis
    3.3.4 Model validation Pore size distribution Pt particle size distribution The average active Pt surface areas
    3.3.5 Coupling electrochemical reactions in CLs
    3.4 Challenges in multi-scale modeling for PEMFC CLs
    3.4.1 The length scales
    3.4.2 The time scales
    3.4.3 The integration algorithms
    3.5 Conclusions

    4. Fabrication of electro-catalytic nano-particles and applications to proton exchange membrane fuel cells Maria Victoria Martínez Huerta & Gonzalo García
    4.1 Introduction
    4.2 Overview of the electro-catalytic reactions
    4.2.1 Hydrogen oxidation reaction
    4.2.2 H2/CO oxidation reaction
    4.2.3 Methanol oxidation reaction
    4.2.4 Oxygen reduction reaction
    4.3 Novel nano-structures of platinum
    4.3.1 State-of-the-art supported Pt catalysts
    4.3.2 Surface structure of Pt catalysts
    4.3.3 Synthesis and performance of Pt catalysts
    4.4 Binary and ternary platinum-based catalysts
    4.4.1 Electro-catalysts for CO and methanol oxidation reactions
    4.4.2 Electro-catalysts for the oxygen reduction reaction
    4.4.3 Synthetic methods of binary/ternary catalysts
    4.5 New electro-catalyst supports
    4.6 Conclusions

    5. Ordered mesoporous carbon-supported nano-platinum catalysts: application in direct methanol fuel cells
    Parasuraman Selvam & Balaiah Kuppan
    5.1 Introduction
    5.2 Ordered mesoporous silicas
    5.3 Ordered mesoporous carbons
    5.3.1 Hard-template approach
    5.3.2 Soft-template approach
    5.4 Direct methanol fuel cell
    5.5 Electrocatalysts for DMFC
    5.5.1 Bulk platinum catalyst
    5.5.2 Platinum alloy catalyst
    5.5.3 Nano-platinum catalyst
    5.5.4 Catalyst promoters
    5.6 OMC-supported platinum catalyst
    5.6.1 Pt/NCCR-41
    5.6.2 Pt/CMK-3
    5.7 Summary and conclusion

    6. Modeling the coupled transport and reaction processes in a micro-solid-oxide fuel cell
    Meng Ni
    6.1 Introduction
    6.2 Model development
    6.2.1 Computational fluid dynamic (CFD) model
    6.2.2 Electrochemical model
    6.2.3 Chemical model
    6.3 Numerical methodologies
    6.4 Results and discussion
    6.4.1 Base case
    6.4.2 Temperature effect
    6.4.3 Operating potential effect
    6.4.4 Effect of electrochemical oxidation rate of CO
    6.5 Conclusions

    7. Nano-structural effect on SOFC durability
    YaoWang & Changrong Xia
    7.1 Introduction
    7.2 Aging mechanism of SOFC electrodes
    7.2.1 Aging mechanism of the anodes Grain coarsening Redox cycling Coking and sulfur poison
    7.2.2 Aging mechanism of cathodes
    7.3 Stability of nano-structured electrodes
    7.3.1 Fabrication and electrochemical properties of nano-structured electrodes
    7.3.2 Models about nano-structured effects on stability Nano-size effects on isothermal grain growth Nano-structured effects on durability against thermal cycle
    7.4 Long-term performance of nano-structured electrodes
    7.4.1 Anodes Enhanced interfacial stabilities of nano-structured anodes Durability of nano-structured anodes against redox cycle Durability of nano-structured anodes against coking and sulfur poisoning
    7.4.2 Cathodes LSM LSC LSCF SSC
    7.5 Summary

    8. Micro- and nano-technologies for microbial fuel cells
    Hao Ren & Junseok Chae
    8.1 Introduction
    8.2 Electricity generation fundamental
    8.2.1 Electron transfer of exoelectrogens
    8.2.2 Voltage generation
    8.2.3 Parameter for MFC characterization Open circuit voltage (EOCV) Areal/volumetric current density (imax,areal, imax,volumetric) and areal/volumetric power density (pmax,areal, pmax,volumetric) Internal resistance (Ri) and areal resistivity (ri) Efficiency – Coulombic efficiency (CE) and energy conversion efficiency (EE) Coulombic efficiency (CE) Energy conversion efficiency (EE) Biofilm morphology
    8.3 Prior art of miniaturized MFCs
    8.4 Promises and future work of miniaturized MFCs
    8.4.1 Promises
    8.4.2 Future work Further enhancing current and power density Applying air-cathodes to replace potassium ferricyanide Reducing the cost of MFCs
    8.5 Conclusion

    9. Microbial fuel cells: the microbes and materials
    Keaton L. Lesnik & Hong Liu
    9.1 Introduction
    9.2 How microbial fuel cells work
    9.3 Understanding exoelectrogens
    9.3.1 Origins of microbe-electrode interactions
    9.3.2 Extracellular electron transfer (EET) mechanisms Redox shuttles/mediators c-type cytochromes Conductive pili
    9.3.3 Interactions and implications
    9.4 Anode materials and modifications
    9.4.1 Carbon-based anode materials
    9.4.2 Anode modifications
    9.5 Cathode materials and catalysts
    9.5.1 Cathode construction
    9.5.2 Catalysts
    9.5.3 Cathode modifications
    9.5.4 Biocathodes
    9.6 Membranes/separators
    9.7 Summary
    9.8 Outlook

    10. Modeling and analysis of miniaturized packed-bed reactors for mobile devices powered by fuel cells
    Srinivas Palanki & Nicholas D. Sylvester
    10.1 Introduction
    10.2 Reactor and fuel cell modeling
    10.2.1 Design equations of the reactor
    10.2.2 Design equations for the fuel cell stack
    10.3 Applications
    10.3.1 Methanol-based system
    10.3.2 Ammonia-based system
    10.4 Conclusions

    11. Photocatalytic fuel cells
    Michael K.H. Leung, BinWang, Li Li & Yiyi She
    11.1 Introduction
    11.2 PFC concept
    11.2.1 Fuel cell
    11.2.2 Photocatalysis
    11.2.3 Photocatalytic fuel cell
    11.3 PFC architecture and mechanisms
    11.3.1 Cell configurations
    11.3.2 Bifunctional photoanode Photocatalyst Substrate materials Catalyst deposition methods
    11.3.3 Cathode
    11.4 Electrochemical kinetics
    11.4.1 Current-voltage characteristics Ideal thermodynamically predicted voltage Activation losses Ohmic losses Concentration losses
    11.4.2 Efficiency of a photocatalytic fuel cell Pseudo-photovoltaic efficiency External quantum efficiency Internal quantum efficiency Current doubling effect
    11.5 PFC applications
    11.5.1 Wastewater problems
    11.5.2 Practical micro-fluidic photocatalytic fuel cell (MPFC) applications
    11.6 Conclusion

    12. Transport phenomena and reactions in micro-fluidic aluminum-air fuel cells
    HuizhiWang, Dennis Y.C. Leung, Kwong-Yu Chan, Jin Xuan & Hao Zhang
    12.1 Introduction
    12.2 Mathematical model
    12.2.1 Problem description
    12.2.2 Cell hydrodynamics
    12.2.3 Charge conservation
    12.2.4 Ionic species transport
    12.2.5 Electrode kinetics Anode kinetics Cathode kinetics Expression of overpotentials
    12.2.6 Boundary conditions
    12.3 Numerical procedures
    12.4 Results and discussion
    12.4.1 Model validation
    12.4.2 Hydrogen distribution
    12.4.3 Velocity distribution
    12.4.4 Species distribution Single-phase flow Ionic species concentration distributions Migration contribution to transverse species transport The effect of bubbles
    12.4.5 Current density and potential distributions
    12.5 Conclusions

    Subject index
    Book series page


    Dennis Y.C. Leung, Jin Xuan