Advertisement

Nano Research

, Volume 4, Issue 9, pp 849–860 | Cite as

Nano-morphology of a polymer electrolyte fuel cell catalyst layer—imaging, reconstruction and analysis

  • Simon ThieleEmail author
  • Roland Zengerle
  • Christoph Ziegler
Research Article

Abstract

The oxygen reduction reaction (ORR) in the cathode catalyst layer (CCL) of polymer electrolyte fuel cells (PEFC) is one of the major causes of performance loss during operation. In addition, the CCL is the most expensive component due to the use of a Pt catalyst. Apart from the ORR itself, the species transport to and from the reactive sites determines the performance of the PEFC. The effective transport properties of the species in the CCL depend on its nanostructure. Therefore a three-dimensional reconstruction of the CCL is required. A series of two-dimensional images was obtained from focused ion beam — scanning electron microscope (FIB-SEM) imaging and a segmentation method for the two-dimensional images has been developed. The pore size distribution (PSD) was calculated for the three-dimensional geometry. The influence of the alignment and the anisotropic pixel size on the PSD has been investigated. Pores were found in the range between 5 nm and 205 nm. Evaluation of the Knudsen number showed that gas transport in the CCL is governed by the transition flow regime. The liquid water transport can be described within continuum hydrodynamics by including suitable slip flow boundary conditions. Open image in new window

Keywords

Cathode catalyst layer (CCL) polymer electrolyte fuel cell (PEFC) tomography three-dimensional reconstruction 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Supplementary material

12274_2011_141_MOESM1_ESM.pdf (430 kb)
Supplementary material, approximately 430 KB.
12274_2011_141_MOESM2_ESM.zip (4.5 mb)
Supplementary material, approximately 4.45 MB.

References

  1. [1]
    Yang, H.; Zhao, T. S.; Ye, Q. Pressure drop behavior in the anode flow field of liquid feed direct methanol fuel cells. J. Power Sources 2005, 142, 117–124.CrossRefGoogle Scholar
  2. [2]
    Manke, I.; Hartnig, C.; Gruenerbel, M.; Lehnert, W.; Kardjilov, N.; Haibel, A.; Hilger, A.; Banhart, J.; Riesemeier, H. Investigation of water evolution and transport in fuel cells with high resolution synchrotron X-ray radiography. Appl. Phys. Lett. 2007, 90, 174105.CrossRefGoogle Scholar
  3. [3]
    Schroeder, A.; Wippermann, K.; Mergel, J.; Lehnert, W.; Stolten, D.; Sanders, T.; Baumhöfer, T.; Sauer, D. U.; Manke, I.; Kardjilov, N. Combined local current distribution measurements and high resolution neutron radiography of operating direct methanol fuel cells. Electrochem. Commun. 2009, 11, 1606–1609.CrossRefGoogle Scholar
  4. [4]
    Sinha, P. K.; Halleck, P.; Wang, C. Y. Quantification of liquid water saturation in a PEM fuel cell diffusion medium using X-ray microtomography. Electrochem. Solid-state Lett. 2006, 9, A344–A348.CrossRefGoogle Scholar
  5. [5]
    Ziegler, C.; Gerteisen, D. Validity of two-phase polymer electrolyte membrane fuel cell models with respect to the gas diffusion layer. J. Power Sources 2009, 188, 184–191.CrossRefGoogle Scholar
  6. [6]
    Xie, Z.; Navessin, T.; Shi, K.; Chow, R.; Wang, Q.; Song, D.; Andreaus, B.; Eikerling, M.; Liu, Z.; Holdcroft, S. Functionally graded cathode catalyst layers for polymer electrolyte fuel cells. J. Electrochem. Soc. 2005, 152, A1171–A1179.CrossRefGoogle Scholar
  7. [7]
    Gerteisen, D.; Heilmann, T.; Ziegler, C. Modeling the phenomena of dehydration and flooding of a polymer electrolyte membrane fuel cell. J. Power Sources 2009, 187, 165–181.CrossRefGoogle Scholar
  8. [8]
    Eikerling, M. Water management in cathode catalyst layers of PEM fuel cells. J. Electrochem. Soc. 2006, 153, E58–E70.CrossRefGoogle Scholar
  9. [9]
    Torquato, S.; Haslach, H. W. Jr. Random Heterogeneous Materials: Microstructure and Macroscopic Properties; Springer: New York, 2002.Google Scholar
  10. [10]
    Mukherjee, P. P.; Wang, C. Y. Direct numerical simulation modeling of bilayer cathode catalyst layers in polymer electrolyte fuel cells. J. Electrochem. Soc. 2007, 154, B1121–B1131.CrossRefGoogle Scholar
  11. [11]
    Levitz, P. Off-lattice reconstruction of porous media: Critical evaluation, geometrical confinement and molecular transport. Adv. Colloid. Interf. Sci. 1998, 76, 71–106.CrossRefGoogle Scholar
  12. [12]
    Torquato, S. Statistical description of microstructures. Annu. Rev. Mater. Res. 2002, 32, 77–111.CrossRefGoogle Scholar
  13. [13]
    Kim, S. H.; Pitsch, H. Reconstruction and effective transport properties of the catalyst layer in PEM fuel cells. J. Electrochem. Soc. 2009, 156, B673–B681.CrossRefGoogle Scholar
  14. [14]
    Siddique, N. A.; Liu, F. Process based reconstruction and simulation of a three-dimensional fuel cell catalyst layer. Electrochim. Acta 2010, 55, 5357–5366.CrossRefGoogle Scholar
  15. [15]
    Möbus, G.; Inkson, B. J. Nanoscale tomography in materials science. Mater. Today 2007, 10, 18–25.CrossRefGoogle Scholar
  16. [16]
    Holzer, L.; Indutnyi, F.; Gasser, P. H.; Munch, B.; Wegmann, M. Three-dimensional analysis of porous BaTiO3 ceramics using FIB nanotomography. J. Microscopy 2004, 216, 84–95.CrossRefGoogle Scholar
  17. [17]
    Wilson, J. R.; Kobsiriphat, W.; Mendoza, R.; Chen, H. Y.; Hiller, J. M.; Miller, D. J.; Thornton, K.; Voorhees, P. W.; Adler, S. B.; Barnett, S. A. Three-dimensional reconstruction of a solid-oxide fuel-cell anode. Nat. Mater. 2006, 5, 541–544.CrossRefGoogle Scholar
  18. [18]
    Ziegler, C.; Thiele, S.; Zengerle, R. Direct three-dimensional reconstruction of a nanoporous catalyst layer for a polymer electrolyte fuel cell. J. Power Sources 2011, 196, 2094–2097.CrossRefGoogle Scholar
  19. [19]
    Holzer, L.; Muench, B.; Wegmann, M.; Gasser, P.; Flatt, R. J. FIB-nanotomography of particulate systems—Part I: Particle shape and topology of interfaces. J. Amer. Ceram. Soc. 2006, 89, 2577–2585.CrossRefGoogle Scholar
  20. [20]
    Abramoff, M. D.; Magalhaes, P. J.; Ram, S. J. Image processing with ImageJ. Biophoton. Int. 2004, 11, 36–43.Google Scholar
  21. [21]
    Thevenaz, P.; Ruttimann, U. E.; Unser, M. A pyramid approach to subpixel registration based on intensity. IEEE Trans. Image Process. 1998, 7, 27–41.CrossRefGoogle Scholar
  22. [22]
    Pal, N. R.; Pal, S. K. A review on image segmentation techniques. Pattern Recog. 1993, 26, 1277–1294.CrossRefGoogle Scholar
  23. [23]
    Munch, B.; Gasser, P.; Holzer, L.; Flatt, R. FIBNanotomography of particulate systems—Part II: Particle recognition and effect of boundary truncation. J. Amer. Ceram. Soc. 2006, 89, 2586–2595.CrossRefGoogle Scholar
  24. [24]
    Ohser, J.; Mücklich, F. Statistical Analysis of Microstructures in Materials Science; John Wiley: New York, 2000.Google Scholar
  25. [25]
    Wilson, J. R.; Cronin, J. S.; Barnett, S. A.; Harris, S. J. Measurement of three-dimensional microstructure in a LiCoO2 positive electrode J. Power Sources 2011, 196, 3443–3447.CrossRefGoogle Scholar
  26. [26]
    Fischer, A.; Jindra, J.; Wendt, H. Porosity and catalyst utilization of thin layer cathodes in air operated PEM-fuel cells. J. Appl. Electrochem. 1998, 28, 277–282.CrossRefGoogle Scholar
  27. [27]
    Delerue, J. F.; Perrier, E.; Yu, Z. Y.; Velde, B. New algorithms in 3D image analysis and their application to the measurement of a spatialized pore size distribution in soils. Phys. Chem Earth A: Solid Earth Geodesy 1999, 24, 639–644.CrossRefGoogle Scholar
  28. [28]
    Soboleva, T.; Zhao, X.; Malek, K.; Xie, Z.; Navessin, T.; Holdcroft, S. On the micro-, meso-, and macroporous structures of polymer electrolyte membrane fuel cell catalyst layers. ACS Appl. Mater. Interf. 2010, 2, 375–384.CrossRefGoogle Scholar
  29. [29]
    Karniadakis, G.; Beskok, A.; Aluru, N. R. Microflows and Nanoflows: Fundamentals and Simulation; Springer Verlag: Berlin, 2005.Google Scholar
  30. [30]
    Schaaf, S. A.; Chambré, P. L. Flow of Rarefied Gases; Princeton University Press: Princeton, 1961.Google Scholar
  31. [31]
    Gad-El-Hak, M. Gas and liquid transport at the microscale. Heat Transf. Eng. 2006, 27, 13–29.CrossRefGoogle Scholar
  32. [32]
    Oran, E. S.; Oh, C. K.; Cybyk, B. Z. Direct simulation Monte Carlo: Recent advances and applications. Annu. Rev. Fluid Mech. 1998, 30, 403–441.CrossRefGoogle Scholar
  33. [33]
    Shen, C.; Tian, D. B.; Xie, C.; Fan, J. Examination of the LBM in simulation of microchannel flow in transitional regime. Nanoscale Microscale Thermophys. Eng. 2004, 8, 423–432.CrossRefGoogle Scholar
  34. [34]
    Kim, S. H.; Pitsch, H.; Boyd, I. D. Lattice Boltzmann modeling of multicomponent diffusion in narrow channels. Phys. Rev. E 2009, 79, 16702.CrossRefGoogle Scholar
  35. [35]
    Zalc, J. M.; Reyes, S. C.; Iglesia, E. Monte Carlo simulations of surface and gas phase diffusion in complex porous structures. Chem. Eng. Sci. 2003, 58, 4605–4617.CrossRefGoogle Scholar
  36. [36]
    Johnson, R. W. The Handbook of Fluid Dynamics; Springer: Heidelberg, 1998.Google Scholar
  37. [37]
    Cheng, J. T.; Giordano, N. Fluid flow through nanometerscale channels. Phys. Rev. E 2002, 65, 31206.CrossRefGoogle Scholar
  38. [38]
    Raviv, U.; Laurat, P.; Klein, J. Fluidity of water confined to subnanometre films. Nature 2001, 413, 51–54.CrossRefGoogle Scholar
  39. [39]
    Raviv, U.; Klein, J. Fluidity of bound hydration layers. Science 2002, 297, 1540–1543.CrossRefGoogle Scholar
  40. [40]
    Leng, Y.; Cummings, P. T. Fluidity of hydration layers nanoconfined between mica surfaces. Phys. Rev. Lett. 2005, 94, 26101.CrossRefGoogle Scholar
  41. [41]
    Thomas, J. A.; McGaughey, A. J. H. Water flow in carbon nanotubes: Transition to subcontinuum transport. Phys. Review Lett. 2009, 102, 184502.CrossRefGoogle Scholar
  42. [42]
    Bocquet, L.; Charlaix, E. Nanofluidics, from bulk to interfaces. Chem. Soc. Rev. 2010, 39, 1073–1095.CrossRefGoogle Scholar
  43. [43]
    Huang, D. M.; Sendner, C.; Horinek, D.; Netz, R. R.; Bocquet, L. Water slippage versus contact angle: A quasiuniversal relationship. Phys. Rev. Lett. 2008, 101, 226101.CrossRefGoogle Scholar
  44. [44]
    Sendner, C.; Horinek, D.; Bocquet, L.; Netz, R. R. Interfacial water at hydrophobic and hydrophilic surfaces: Slip, viscosity, and diffusion. Langmuir 2009, 25, 10768–10781.CrossRefGoogle Scholar
  45. [45]
    Tandon, V.; Kirby, B. J. Zeta potential and electroosmotic mobility in microfluidic devices fabricated from hydrophobic polymers: 2. Slip and interfacial water structure. Electrophoresis 2008, 29, 1102–1114.CrossRefGoogle Scholar
  46. [46]
    Jawhari, T.; Roid, A.; Casado, J. Raman spectroscopic characterization of some commercially available carbon black materials. Carbon 1995, 33, 1561–1565.CrossRefGoogle Scholar
  47. [47]
    Mattia, D.; Gogotsi, Y. Review: Static and dynamic behavior of liquids inside carbon nanotubes. Microfluid. Nanofluid. 2008, 5, 289–305.CrossRefGoogle Scholar
  48. [48]
    Bass, M.; Berman, A.; Singh, A.; Konovalov, O.; Freger, V. Surface structure of Nafion in vapor and liquid. J. Phys. Chem. B 2010, 114, 3784–3790.CrossRefGoogle Scholar

Copyright information

© Tsinghua University Press and Springer-Verlag Berlin Heidelberg 2011

Authors and Affiliations

  • Simon Thiele
    • 1
    Email author
  • Roland Zengerle
    • 1
  • Christoph Ziegler
    • 1
  1. 1.Laboratory for MEMS Applications, Department of Microsystems Engineering—IMTEKUniversity of FreiburgFreiburgGermany

Personalised recommendations