Measuring fundamental properties in operating solid oxide electrochemical cells by using in situ x-ray photoelectron spectroscopy

ABSTRACT Photoelectron spectroscopic measurements have the potential to provide detailed mechanistic insight by resolving chemical states, electrochemically active regions and local

potentials or potential losses in operating solid oxide electrochemical cells (SOCs), such as fuel cells. However, high-vacuum requirements have limited X-ray photoelectron spectroscopy

(XPS) analysis of electrochemical cells to _ex situ_ investigations. Using a combination of ambient-pressure XPS and CeO2−_x_/YSZ/Pt single-chamber cells, we carry out _in situ_ spectroscopy

to probe oxidation states of all exposed surfaces in operational SOCs at 750 °C in 1 mbar reactant gases H2 and H2O. Kinetic energy shifts of core-level photoelectron spectra provide a

direct measure of the local surface potentials and a basis for calculating local overpotentials across exposed interfaces. The mixed ionic/electronic conducting CeO2−_x_ electrodes undergo

Ce3+/Ce4+ oxidation–reduction changes with applied bias. The simultaneous measurements of local surface Ce oxidation states and electric potentials reveal the active ceria regions during H2

electro-oxidation and H2O electrolysis. The active regions extend ∼150 μm from the current collectors and are not limited by the three-phase-boundary interfaces associated with other SOC

materials. The persistence of the Ce3+/Ce4+ shifts in the ∼150 μm active region suggests that the surface reaction kinetics and lateral electron transport on the thin ceria electrodes are

co-limiting processes. Access through your institution Buy or subscribe This is a preview of subscription content, access via your institution ACCESS OPTIONS Access through your institution

Subscribe to this journal Receive 12 print issues and online access $259.00 per year only $21.58 per issue Learn more Buy this article * Purchase on SpringerLink * Instant access to full

article PDF Buy now Prices may be subject to local taxes which are calculated during checkout ADDITIONAL ACCESS OPTIONS: * Log in * Learn about institutional subscriptions * Read our FAQs *

Contact customer support SIMILAR CONTENT BEING VIEWED BY OTHERS REVEALING SOLID ELECTROLYTE INTERPHASE FORMATION THROUGH INTERFACE-SENSITIVE _OPERANDO_ X-RAY ABSORPTION SPECTROSCOPY Article

Open access 14 October 2022 OPERANDO ANALYSIS OF A SOLID OXIDE FUEL CELL BY ENVIRONMENTAL TRANSMISSION ELECTRON MICROSCOPY Article Open access 02 December 2023 COMPUTATIONAL ENGINEERING OF

THE OXYGEN ELECTRODE-ELECTROLYTE INTERFACE IN SOLID OXIDE FUEL CELLS Article Open access 23 July 2021 REFERENCES * Atkinson, A. et al. Advanced anodes for high-temperature fuel cells.

_Nature Mater._ 3, 17–27 (2004). Article  CAS  Google Scholar  * Minh, N. Q. Ceramic fuel-cells. _J. Am. Ceram. Soc._ 76, 563–588 (1993). Article  CAS  Google Scholar  * Huang, Y. H., Dass,

R. I., Xing, Z. L. & Goodenough, J. B. Double perovskites as anode materials for solid-oxide fuel cells. _Science_ 312, 254–257 (2006). Article  CAS  Google Scholar  * Zhan, Z. L. &

Barnett, S. A. An octane-fueled solid oxide fuel cell. _Science_ 308, 844–847 (2005). Article  CAS  Google Scholar  * Adler, S. B. Factors governing oxygen reduction in solid oxide fuel cell

cathodes. _Chem. Rev._ 104, 4791–4843 (2004). Article  CAS  Google Scholar  * Haile, S. M. Fuel cell materials and components. _Acta Mater._ 51, 5981–6000 (2003). Article  CAS  Google

Scholar  * Steele, B. C. H. & Heinzel, A. Materials for fuel-cell technologies. _Nature_ 414, 345–352 (2001). Article  CAS  Google Scholar  * Brandon, N. P., Skinner, S. & Steele, B.

C. H. Recent advances in materials for fuel cells. _Annu. Rev. Mater. Res._ 33, 183–213 (2003). Article  CAS  Google Scholar  * Shao, Z. P. & Haile, S. M. A high-performance cathode for

the next generation of solid-oxide fuel cells. _Nature_ 431, 170–173 (2004). Article  CAS  Google Scholar  * Esch, F. et al. Electron localization determines defect formation on ceria

substrates. _Science_ 309, 752–755 (2005). Article  CAS  Google Scholar  * Fleig, J. On the width of the electrochemically active region in mixed conducting solid oxide fuel cell cathodes.

_J. Power Sources_ 105, 228–238 (2002). Article  CAS  Google Scholar  * Mogensen, M., Sammes, N. M. & Tompsett, G. A. Physical, chemical and electrochemical properties of pure and doped

ceria. _Solid State Ion._ 129, 63–94 (2000). Article  CAS  Google Scholar  * Yang, L. et al. Enhanced sulfur and coking tolerance of a mixed ion conductor for SOFCs:

BaZr0.1Ce0.7Y0.2−_x_Yb_x_O3−_δ_ . _Science_ 326, 126–129 (2009). Article  CAS  Google Scholar  * Campbell, C. T. & Peden, C. H. F. Chemistry—oxygen vacancies and catalysis on ceria

surfaces. _Science_ 309, 713–714 (2005). Article  CAS  Google Scholar  * Fu, Q., Saltsburg, H. & Flytzani-Stephanopoulos, M. Active nonmetallic Au and Pt species on ceria-based water-gas

shift catalysts. _Science_ 301, 935–938 (2003). Article  CAS  Google Scholar  * Murray, E. P., Tsai, T. & Barnett, S. A. A direct-methane fuel cell with a ceria-based anode. _Nature_

400, 649–651 (1999). Article  CAS  Google Scholar  * Ganduglia-Pirovano, M. V., Hofmann, A. & Sauer, J. Oxygen vacancies in transition metal and rare earth oxides: Current state of

understanding and remaining challenges. _Surf. Sci. Rep._ 62, 219–270 (2007). Article  CAS  Google Scholar  * Trovarelli, A. in _Catalysis by Ceria and Related Materials_ (ed. Trovarelli,

A.) Ch. 2 (Imperial College Press, 2002). Book  Google Scholar  * Hsieh, G., Mason, T. O., Garboczi, E. J. & Pederson, L. R. Experimental limitations in impedance spectroscopy. 3. Effect

of reference electrode geometry/position. _Solid State Ion._ 96, 153–172 (1997). Article  CAS  Google Scholar  * Krishnan, V. V., McIntosh, S., Gorte, R. J. & Vohs, J. M. Measurement of

electrode overpotentials for direct hydrocarbon conversion fuel cells. _Solid State Ion._ 166, 191–197 (2004). Article  CAS  Google Scholar  * Schichlein, H., Muller, A. C., Voigts, M.,

Krugel, A. & Ivers-Tiffee, E. Deconvolution of electrochemical impedance spectra for the identification of electrode reaction mechanisms in solid oxide fuel cells. _J. Appl.

Electrochem._ 32, 875–882 (2002). Article  CAS  Google Scholar  * Metzger, P., Friedrich, K. A., Muller-Steinhagen, H. & Schiller, G. SOFC characteristics along the flow path. _Solid

State Ion._ 177, 2045–2051 (2006). Article  CAS  Google Scholar  * Chan, S. H., Chen, X. J. & Khor, K. A. Reliability and accuracy of measured overpotential in a three-electrode fuel

cell system. _J. Appl. Electrochem._ 31, 1163–1170 (2001). Article  CAS  Google Scholar  * Winkler, J., Hendriksen, P. V., Bonanos, N. & Mogensen, M. Geometric requirements of solid

electrolyte cells with a reference electrode. _J. Electrochem. Soc._ 145, 1184–1192 (1998). Article  CAS  Google Scholar  * Pomfret, M. B. et al. Hydrocarbon fuels in solid oxide fuel cells:

_In situ_ Raman studies of graphite formation and oxidation. _J. Phys. Chem. C_ 112, 5232–5240 (2008). Article  CAS  Google Scholar  * Pomfret, M. B., Owrutsky, J. C. & Walker, R. A.

_In situ_ studies of fuel oxidation in solid oxide fuel cells. _Anal. Chem._ 79, 2367–2372 (2007). Article  CAS  Google Scholar  * Cheng, Z. & Liu, M. L. Characterization of sulfur

poisoning of Ni–YSZ anodes for solid oxide fuel cells using _in situ_ Raman micro spectroscopy. _Solid State Ion._ 178, 925–935 (2007). Article  CAS  Google Scholar  * Sumi, H. et al.

Changes of internal stress in solid-oxide fuel cell during red-ox cycle evaluated by _in situ_ measurement with synchrotron radiation. _J. Fuel Cell Sci. Technol._ 3, 68–74 (2006). Article 

CAS  Google Scholar  * Liu, D. J. & Almer, J. Phase and strain distributions associated with reactive contaminants inside of a solid oxide fuel cell. _Appl. Phys. Lett._ 94, 224106

(2009). Article  Google Scholar  * Wilson, J. R. et al. Three-dimensional reconstruction of a solid-oxide fuel-cell anode. _Nature Mater._ 5, 541–544 (2006). Article  CAS  Google Scholar  *

Fister, T. T. et al. _In situ_ characterization of strontium surface segregation in epitaxial La0.7Sr0.3MnO3 thin films as a function of oxygen partial pressure. _Appl. Phys. Lett._ 93,

151904 (2008). Article  Google Scholar  * Ogletree, D. F., Bluhm, H., Hebenstreit, E.D. & Salmeron, M. Photoelectron spectroscopy under ambient pressure and temperature conditions.

_Nucl. Instrum. Methods Phys. Res._ 601, 151–160 (2009). Article  Google Scholar  * Salmeron, M. & Schlogl, R. Ambient pressure photoelectron spectroscopy: A new tool for surface science

and nanotechnology. _Surf. Sci. Rep._ 63, 169–199 (2008). Article  CAS  Google Scholar  * Siegbahn, H. & Lundholm, M. A method of depressing gaseous-phase electron lines in liquid-phase

ESCA spectra. _J. Electron Spectrosc. Relat. Phenom._ 28, 135–138 (1982). Article  CAS  Google Scholar  * Doron-Mor, H. et al. Controlled surface charging as a depth-profiling probe for

mesoscopic layers. _Nature_ 406, 382–385 (2000). Article  CAS  Google Scholar  * Ertas, G. & Suzer, S. in _Surface Chemistry in Biomedical and Environmental Science_ (eds Blitz, J. P.

& Gun’ko, V. M.) Ch. 5 (Springer, 2006). Google Scholar  * Ladas, S., Kennou, S., Bebelis, S. & Vayenas, C. G. Origin of non-Faradaic electrochemical modification of catalytic

activity. _J. Phys. Chem._ 97, 8845–8848 (1993). Article  CAS  Google Scholar  * Bard, A. J. & Faulkner, L. R. _Electrochemical Methods, Fundamentals and Applications_ (John Wiley,

2001). Google Scholar  * Vetter, K. J. _Electrochemical Kinetics: Theoretical and Experimental Aspects_ (Academic, 1967). Google Scholar  * Mogensen, M. in _The CRC Handbook of Solid State

Electrochemistry_ (ed. Trovarelli, A.) Ch. 15 (CRC Press, 1997). Google Scholar  * Kwon, O. H. & Choi, G. M. Electrical conductivity of thick film YSZ. _Solid State Ion._ 177, 3057–3062

(2006). CAS  Google Scholar  * Grass, M. E. et al. New ambient pressure photoemission endstation at Advanced Light Source beamline 9.3.2. _Rev. Sci. Instrum._ 81, 053106 (2010). Article 

Google Scholar  * Mullins, D. R., Overbury, S. H. & Huntley, D. R. Electron spectroscopy of single crystal and polycrystalline cerium oxide surfaces. _Surf. Sci._ 409, 307–319 (1998).

Article  CAS  Google Scholar  * Fleig, J. On the current–voltage characteristics of charge transfer reactions at mixed conducting electrodes on solid electrolytes. _Phys. Chem. Chem. Phys._

7, 2027–2037 (2005). Article  CAS  Google Scholar  Download references ACKNOWLEDGEMENTS This work was financially supported by the ONR through Contract number N000140510711. We thank the

University of Maryland Nanocenter and the University of Maryland Energy Research Center (UMERC) for support. The Advanced Light Source is supported by the Director, Office of Science, Office

of Basic Energy Sciences, of the US Department of Energy under Contract No. DE-AC02-05CH11231. Work at Sandia National Laboratories is supported by the Laboratory Directed Research and

Development programme under contract DE-AC04-94AL85000 of the United States Department of Energy. AUTHOR INFORMATION Author notes * Mark A. Linne Present address: Present address: Chalmers

University of Technology, 41296 Gothenburg, Sweden, AUTHORS AND AFFILIATIONS * Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA Chunjuan

Zhang & Bryan W. Eichhorn * Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA Michael E. Grass, Zhi Liu & Zahid Hussain * Sandia National

Laboratories, Livermore, California 94551, USA Anthony H. McDaniel, Farid El Gabaly, Kevin F. McCarty, Roger L. Farrow & Mark A. Linne * Department of Mechanical Engineering, University

of Maryland, College Park, Maryland 20742, USA Steven C. DeCaluwe & Gregory S. Jackson * Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720,

USA Hendrik Bluhm Authors * Chunjuan Zhang View author publications You can also search for this author inPubMed Google Scholar * Michael E. Grass View author publications You can also

search for this author inPubMed Google Scholar * Anthony H. McDaniel View author publications You can also search for this author inPubMed Google Scholar * Steven C. DeCaluwe View author

publications You can also search for this author inPubMed Google Scholar * Farid El Gabaly View author publications You can also search for this author inPubMed Google Scholar * Zhi Liu View

author publications You can also search for this author inPubMed Google Scholar * Kevin F. McCarty View author publications You can also search for this author inPubMed Google Scholar *

Roger L. Farrow View author publications You can also search for this author inPubMed Google Scholar * Mark A. Linne View author publications You can also search for this author inPubMed 

Google Scholar * Zahid Hussain View author publications You can also search for this author inPubMed Google Scholar * Gregory S. Jackson View author publications You can also search for this

author inPubMed Google Scholar * Hendrik Bluhm View author publications You can also search for this author inPubMed Google Scholar * Bryan W. Eichhorn View author publications You can also

search for this author inPubMed Google Scholar CONTRIBUTIONS All co-authors contributed to the conception and design of experiments. The ALS team collected and analysed the XPS data. The

Sandia team collected the electrochemical data. The Maryland team fabricated and characterized cells and collated data analysis. Z.H. and M.A.L. initiated and partially financially supported

the collaboration. CORRESPONDING AUTHORS Correspondence to Gregory S. Jackson, Hendrik Bluhm or Bryan W. Eichhorn. ETHICS DECLARATIONS COMPETING INTERESTS The authors declare no competing

financial interests. SUPPLEMENTARY INFORMATION SUPPLEMENTARY INFORMATION Supplementary Information (PDF 440 kb) RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS

ARTICLE Zhang, C., Grass, M., McDaniel, A. _et al._ Measuring fundamental properties in operating solid oxide electrochemical cells by using _in situ_ X-ray photoelectron spectroscopy.

_Nature Mater_ 9, 944–949 (2010). https://doi.org/10.1038/nmat2851 Download citation * Received: 24 February 2010 * Accepted: 06 August 2010 * Published: 26 September 2010 * Issue Date:

November 2010 * DOI: https://doi.org/10.1038/nmat2851 SHARE THIS ARTICLE Anyone you share the following link with will be able to read this content: Get shareable link Sorry, a shareable

link is not currently available for this article. Copy to clipboard Provided by the Springer Nature SharedIt content-sharing initiative