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Engineering

Probing and Mapping Electrode Surfaces in Solid Oxide Fuel Cells

Published: September 20th, 2012

DOI:

10.3791/50161

1Center for Innovative Fuel Cells and Battery Technologies, School of Materials Science and Engineering, Georgia Institute of Technology , 2School of Chemistry and Biochemistry, Georgia Institute of Technology

We present a unique platform for characterizing electrode surfaces in solid oxide fuel cells (SOFCs) that allows simultaneous performance of multiple characterization techniques (e.g. in situ Raman spectroscopy and scanning probe microscopy alongside electrochemical measurements). Complementary information from these analyses may help to advance toward a more profound understanding of electrode reaction and degradation mechanisms, providing insights into rational design of better materials for SOFCs.

Solid oxide fuel cells (SOFCs) are potentially the most efficient and cost-effective solution to utilization of a wide variety of fuels beyond hydrogen 1-7. The performance of SOFCs and the rates of many chemical and energy transformation processes in energy storage and conversion devices in general are limited primarily by charge and mass transfer along electrode surfaces and across interfaces. Unfortunately, the mechanistic understanding of these processes is still lacking, due largely to the difficulty of characterizing these processes under in situ conditions. This knowledge gap is a chief obstacle to SOFC commercialization. The development of tools for probing and mapping surface chemistries relevant to electrode reactions is vital to unraveling the mechanisms of surface processes and to achieving rational design of new electrode materials for more efficient energy storage and conversion2. Among the relatively few in situ surface analysis methods, Raman spectroscopy can be performed even with high temperatures and harsh atmospheres, making it ideal for characterizing chemical processes relevant to SOFC anode performance and degradation8-12. It can also be used alongside electrochemical measurements, potentially allowing direct correlation of electrochemistry to surface chemistry in an operating cell. Proper in situ Raman mapping measurements would be useful for pin-pointing important anode reaction mechanisms because of its sensitivity to the relevant species, including anode performance degradation through carbon deposition8, 10, 13, 14 ("coking") and sulfur poisoning11, 15 and the manner in which surface modifications stave off this degradation16. The current work demonstrates significant progress towards this capability. In addition, the family of scanning probe microscopy (SPM) techniques provides a special approach to interrogate the electrode surface with nanoscale resolution. Besides the surface topography that is routinely collected by AFM and STM, other properties such as local electronic states, ion diffusion coefficient and surface potential can also be investigated17-22. In this work, electrochemical measurements, Raman spectroscopy, and SPM were used in conjunction with a novel test electrode platform that consists of a Ni mesh electrode embedded in an yttria-stabilized zirconia (YSZ) electrolyte. Cell performance testing and impedance spectroscopy under fuel containing H2S was characterized, and Raman mapping was used to further elucidate the nature of sulfur poisoning. In situ Raman monitoring was used to investigate coking behavior. Finally, atomic force microscopy (AFM) and electrostatic force microscopy (EFM) were used to further visualize carbon deposition on the nanoscale. From this research, we desire to produce a more complete picture of the SOFC anode.

1. Fabrication of a YSZ-embedded Mesh Anode Cell

  1. Weigh out two batches of 0.2 g of YSZ powder.
  2. Compress one batch YSZ powder in a cylindrical stainless steel mold (13 mm in diameter) with a uniaxial dry press at a pressure of 50 MPa for 30 sec.
  3. Cut a <1-cm piece of Ni mesh and place it onto the surface of YSZ disc inside the mold.
  4. Add the other 0.2 g of YSZ powder on top of the Ni-mesh inside the mold and flatten the surface of the powder using a ram.
  5. Uniaxially pres.......

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Sulfur Poisoning Analysis

Shown in Figure 4 are typical I-V and I-P curves of a cell with a Ni mesh electrode under H2 and 20 ppm H2S condition. Clearly, the introduction of even just a few ppm of H2S can poison the Ni-YSZ anode and cause considerable performance degradation.

In order to more intensively understand the poisoning behavior of the Ni-YSZ anode, AC impedance spectroscopy of the cell was performed under open.......

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Sulfur Poisoning Analysis

The impedance spectra shown in Figure 5 suggest that sulfur poisoning is a surface or interfacial phenomenon rather than one that affects the bulk of the material. Specifically, the quick poisoning of the Ni mesh electrode (Figure 6) might result from the direct exposure of Ni electrode to the fuel gas and subsequent sulfur adsorption; gas diffusion would not limit the rate of this process as much as in the case of a thick porous Ni/YSZ .......

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This work was supported by the HeteroFoaM Center, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences (BES) under Award Number DE-SC0001061.

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Name Company Catalog Number Comments
Name of Reagent/Material Company Catalog Number Comments
Nickel mesh Alfa Aesar CAS: 7440-02-0  
Ni Foil Alfa Aesar CAS: 7440-02-0  
YSZ powder TOSOH Lot No:S800888B  
Ag paste Heraeus C8710  
Barium oxide Sigma-Aldrich 1304-28-5  
Silver wire Alfa Aesar 7440-22-4  
Acetone VWR 67-64-1  
Ethanol Alfa Aesar 64-17-5  
UHP H2 Airgas   99.999% purity
100 ppm H2S/H2 Airgas   Certified custom mix
n-type Si AFM tip MikroMasch NSC16 10 nm tip radius
Au coated AFM tip MikroMasch CSC11/Au/Cr 20-30 nm tip radius
Raman Spectrometer Renishaw RM1000  
Ar Ion laser ModuLaser StellarPro 150  
He-Ne laser Thorlabs HPL170  
Atomic Force Microscope Veeco Nanoscope IIIA  
Moving Raman Stage Prior Scientific H101RNSW  
Optical Microscope Leica DMLM  
Scanning Electron Microscope LEO 1550  
Tube Furnace Applied Test Systems 2110  
Polisher Allied High Tech Products MetPrep  
6 μm Grinding media Allied High Tech Products 50-50040M  
3 μm Polishing media Allied High Tech Products 90-30020  
1 μm Polishing media Allied High Tech Products 90-30015  
0.1 μm Polishing media Allied High Tech Products 90-32000  
Raman chamber Harrick Scientific HTRC  

  1. Minh, N. Q. Solid oxide fuel cell technology-features and applications. Solid State Ionics. 174 (1-4), 271 (2004).
  2. Liu, M., Lynch, M. E., Blinn, K., Alamgir, F., Choi, Y. Rational SOFC material design: new advances and tools. Materials today. 14 (11), 534 (2011).
  3. Zhan, Z. L., Barnett, S. A. An octane-fueled solid oxide fuel cell. Science. 308, 844 (2005).
  4. Huang, Y. H., Dass, R. I., Xing, Z. L., Goodenough, J. B. Double perovskites as anode materials for solid oxide fuel cells. Science. 312, 254 (2006).
  5. Yang, L., Wang, S., Blinn, K., Liu, M., Liu, Z., Cheng, Z., Liu, M. Enhanced Sulfur and Coking Tolerance of a Mixed Ion Conductor for SOFCs: BaZr0.1Ce0.7Y0.2-xYbxO3-d. Science. 326, 126 (2009).
  6. Liu, M. F., Choi, Y. M., Yang, L., Blinn, K., Qin, W., Liu, P., Liu, M. L. Direct octane fuel cells: A promising power for transportation. Nano Energy. 1, 448 (2012).
  7. Cheng, Z., Wang, J. -. H., Choi, Y. M., Yang, L., Lin, M. C., Liu, M. From Ni-YSZ to sulfur-tolerant anodes for SOFCs: electrochemical behavior, in situ characterization, modeling, and future perspectives. Energy & Environmental Science. 4 (11), 4380 (2011).
  8. Blinn, K. S., Abernathy, H. W., Li, X., Liu, M. F., Liu, M. Raman spectroscopic monitoring of carbon deposition on hydrocarbon-fed solid oxide fuel cell anodes. Energy & Environmental Science. 5, 7913 (2012).
  9. Abernathy, H. W. . Investigations of Gas/Electrode Interactions in Solid Oxide Fuel Cells Using Vibrational Spectroscopy [dissertation]. , (2008).
  10. Pomfret, M. B., Owrutsky, J. C., Walker, R. A. High-temperature Raman spectroscopy of solid oxide fuel cell materials and processes. Journal of Physical Chemistry B. 110 (35), 17305 (2006).
  11. Cheng, Z., Liu, M. Characterization of sulfur poisoning of Ni-YSZ anodes for solid oxide fuel cells using in situ Raman microspectroscopy. Solid State Ionics. 178 (13-14), 925 (2007).
  12. Li, X., Blinn, K., Fang, Y., Liu, M., Mahmoud, M. A., Cheng, S., Bottomley, L. A., El-Sayed, M., Liu, M. Application of surface enhanced Raman spectroscopy to the study of SOFC electrode surfaces. Physical Chemistry Chemical Physics. 14, 5919 (2012).
  13. Dresselhaus, M. S., Jorio, A., Hofmann, M., Dresselhaus, G., Saito, R. Perspectives on Carbon Nanotubes and Graphene Raman Spectroscopy. Nano Letters. 10, 751 (2010).
  14. Su, C., Ran, R., Wang, W., Shao, Z. P. Coke formation and performance of an intermediate-temperature solid oxide fuel cell operating on dimethyl ether fuel. Journal of Power Sources. 196, 1967 (2011).
  15. Cheng, Z., Abernathy, H., Raman Liu, M. Spectroscopy of Nickel Sulfide Ni3S2. Journal of Physical Chemistry C. 111 (49), 17997 (2007).
  16. Yang, L., Choi, Y., Qin, W., Chen, H., Blinn, K., Liu, M., Liu, P., Bai, J., Tyson, T. A., Liu, M. Promotion of water-mediated carbon removal bynanostructured barium oxide/nickel interfaces in solid oxide fuel cells. Nature Communications. 2, 357 (2011).
  17. Kumar, A., Ciucci, F., Morzovska, A., Kalinin, S., Jesse, S. Measuring oxygen reduction/evolution reactions on the nanoscale. Nature Chemistry. 3, 707 (2011).
  18. Kumar, A., Arruda, T. M., Kim, Y., Ivanov, I. N., Jesse, S., Bark, C. W., Bristowe, N. C., Artacho, E., Littlewood, P. B., Eom, C. B., Kalinin, S. V. Probing Surface and Bulk Electrochemical Processes on the LaAlO3-SrTiO3 Interface. ACS Nano. 6 (5), 3841 (2012).
  19. Katsiev, K., Yildiz, B., Balasubramaniam, K., Salvador, P. A. Electron Tunneling Characteristics on La0.7Sr0.3MnO3 Thin-Film Surfaces at High Temperature. Applied Physics Letters. 95 (9), 092106 (2009).
  20. Jesse, S., Kumar, A., Arruda, T. M., Kim, Y., Kalinin, S. V., Ciucci, F. Electrochemical strain microscopy: Probing ionic and electrochemical phenomena in solids at the nanometer level. MRS Bulletin. 37 (7), 651-65 (2012).
  21. Datta, S. S., Strachan, D. R., Mele, E. J., Johnson, A. T. Surface Layers and Layer Charge Distributions in Few-Layer Graphene Films. Nano Letters. 9, 7 (2009).
  22. Coffey, D. C., Ginger, D. S. Time-resolved electrostatic force microscopy of polymer solar cells. Nature Materials. 5 (9), 735 (2006).
  23. Nakamura, M., Yamada, H., Morita, S. . Roadmap of Scanning Probe Microscopy. , (2007).
  24. Girard, P. Electrostatic force microscopy: principles and some applications to semiconductors. Nanotechnology. 12, 485 (2001).
  25. Rasmussen, J. F. B., Hagen, A. The effect of H2S on the performance of Ni-YSZ anodes in solid oxide fuel cells. Journal of Power Sources. 191 (2), 534 (2009).
  26. Zha, S. W., Cheng, Z., Liu, M. L. Sulfur poisoning and regeneration of Ni-based anodes in solid oxide fuel cells. Journal of The Electrochemical Society. 154 (2), B201 (2007).
  27. Liu, M. F., Ding, D., Blinn, K., Li, X., Nie, L., Liu, M. L. Enhanced performance of LSCF cathode through surface modification. International Journal of Hydrogen Energy. 37 (10), 8613 (2012).
  28. Park, H., Li, X., Blinn, K. S., Liu, M., Lai, S., Bottomley, L. A., Liu, M., Park, S. Probing coking resistance from nanoscale: a study of patterned BaO nanorings over nickel surface. , (2012).

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