2-Dimensional Ion Conducting Bismuth Vanadates for Electrochemical Devices

• Applicant: Professor Dr.-Ing. Ralf Moos
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2012 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 198685931

• Final Report Year: 2015

Final Report Abstract

Bismuth vanadate compounds are of high interest due to their high ionic conductivity, especially at moderate temperatures between 300 and 500 °C. Therefore, a large potential exists for a usage in the field of fuel cells, oxygen separation membranes and gas sensing devices. The project “2-Dimensional Ion Conducting Bismuth Vanadates for Electrochemical Devices” was a collaborative project between DFG and NSF, in the framework of Materials World Network. Project goals were the detailed investigation of material stability and properties as well as to explore their suitability for electrochemical devices. The main findings of the project are the following:  Modest texturing of bismuth vanadate bulk samples up to 16 % can be achieved by hot forging. Samples were characterized and showed anisotropic properties for ionic conductivity as well as thermal expansion. Thermal aging at 400 and 500 °C as well as stability towards low oxygen partial pressures were investigated. While at 500 °C all samples were stable and conductivity was constant for a time period of 48 h, textured samples showed a decrease in conductivity when held at 400 °C. This is probably caused by a γ-γ' phase transition, that comes with an ordering of oxygen vacancies. Dense thick films of doped bismuth vanadate were produced for the first time using a novel spray coating method called aerosol deposition (AD). The after treatment was investigated in detail and already moderate annealing at 500 °C yield an ionic conductivity close to the bulk value. The release of non-uniform lattice strain was identified as the main reason for the increase of conductivity during annealing. AD films showed improved strength, adhesion and ionic conductivity compared to conventional screen-printed films.  By aerosol codeposition dense composite films of a Bi2O3:V2O5 mixture can be deposited, however a change in composition occurred during the process. In situ calcination of the composite film was possible and lead to stable, but porous BiVO4 films.  A planar NO2 sensor was prepared by aerosol deposition of bismuth vanadate. The sensor utilizes the pulse polarization technique and it was achieved to measure small concentrations of NO2 without any sensitivity to NO.

Publications

• Aerosol Co-Deposition of Bi2O3 and TiO2 and in-situ formation of Bi4Ti3O12, Electroceramics XIV, Bucharest, Romania, 16.06.-20.06.2014, p. 357-358
  J. Exner, P. Fuierer, R. Moos
  
• Aerosol Codeposition of Ceramics: Mixtures of Bi2O3-TiO2 and Bi2O3-V2O5, J. Am. Ceram. Soc., 98, 717–723 (2014)
  J. Exner, P. Fuierer, R. Moos
  
• Aerosol deposition of (Cu,Ti) substituted bismuth vanadate films, Thin Solid Films, 573, 185–190 (2014)
  J. Exner, P. Fuierer, R. Moos
  
• Aerosol Deposition of Bismuth Vanadates, Solid State Ionics 18, Kyoto, Japan, Abstracts, 02.06.-07.06.2014, p. 132
  J. Exner, M. Maier, P. Fuierer, R. Moos
  
• Anisotropy and thermal stability of hot-forged BICUTIVOX oxygen ion conducting ceramics, Journal of the European Ceramic Society, 34, 943–951 (2014)
  P. Fuierer, M. Maier, J. Exner, R. Moos
  
• Hot-forging of copper substituted bismuth vanadate ceramics, The 26th Rio Grande Symposium on Advanced Materials, Albuquerque, New Mexico, 06.10.2014, P 24
  K. Ring, R. Reprogle, P. Fuierer
  
• Room temperature aerosol deposition process for dense ceramic coatings - functional principle and applications, The 26th Rio Grande Symposium on Advanced Materials, Albuquerque, New Mexico, 06.10.2014, P 24
  J. Exner, D. Hanft, P. Fuierer, R. Moos
  
• An Overview of the Aerosol Deposition Method: Process Fundamentals and New Trends in Materials Applications, Journal of Ceramic Science and Technology, 6, 147-182 (2015)
  D. Hanft, J. Exner, M. Schubert, T. Stöcker, P. Fuierer, R. Moos
  
• BIMEVOX ceramics as an intermediate temperature SOFC electrolyte: Another look, 11th International Conference on Ceramic Materials and Components for Energy and Environmental Applications, Vancouver, Canada, 14.06.-19.06.2015
  P. A. Fuierer, K. Ring, J. Exner, R. Moos
  
• Microstructure and Stability of Bi4V2-x-y(CuxTiy)O11-δ Ceramics, 7th International Conference on Electroceramics (ICE2015), State College, PA, USA, 13.05.-16.05.2015, p. 4-O-02
  K. Ring, R. Moos, P. Fuierer
  
• NO2 Detection by Pulsed Polarization of Doped Bismuth Vanadate films prepared by the Aerosol Deposition Method, 7th International Conference on Electroceramics (ICE2015), State College, PA, USA, 13.05.-16.05.2015, p. 3-O-02
  J. Exner, G. Albrecht, P. Fuierer, R. Moos
  
• Powder requirements for Aerosol Deposition of alumina films, 90. DKG Jahrestagung / Symposium Hochleistungskeramik 2015, Bayreuth, 15.03.-19.03.2015, p. 51
  J. Exner, M. Hahn, M. Schubert, D. Hanft, R. Moos, P. Fuierer
  
• BICU(TI)VOX as a low/intermediate temperature SOFC electrolyte: Another look. In: Thomas Pfeifer, Josef Matyáš, Palani Balaya, Dileep Singh, John Wei (eds): Ceramics for Energy Conversion, Storage, and Distribution Systems (Ceramic Transactions Series, Volume 255, CCLV) 20160531. Print ISBN: 9781119234487
  P. Fuierer, K. Ring, J. Exner, R. Moos