11-13 November 2019
Africa/Johannesburg timezone
SA-ESRF Light Source Conference

The Search for an Improved SOFC Electrolyte Material: Stabilizing the Fm3 ̅m Phase of Bismuth Oxide to Lower Temperatures

11 Nov 2019, 17:00
1st Floor : Gold and Sliver Rooms and Sundowners (12 floor)

1st Floor : Gold and Sliver Rooms and Sundowners (12 floor)

Poster Materials Poster Session 1


Mr Mathias Kiefer (Wits University)


SOFCs have emerged as a leading candidate in the search for an efficient and environmentally friendly source of electrical energy.[1-7] SOFCs are, however, marred by a variety of limitations[1,4,6] which have prevented the widespread commercialization of this technology. Most of these limitations stem from the high operating temperature (typically 800-1000 °C) that is associated with these cells – a feature dictated by the electrolyte material. As such, there exists a need for an improved electrolyte; a material that will display high oxide ion conduction at substantially lower temperatures. One such candidate is the Fm¯3m-structured δ-polymorph of Bi2O3 – the highest known oxide ion conductor. Normally only stable within a high and narrow temperature range (730-824 °C),[1] this cubic polymorph has been exclusively studied in this work with the primary aim of stabilizing the δ-polymorph structure to lower temperatures by means of yttrium doping. These attempts have been successful; various YxBi2-xO3 members have been found to display the Fm¯3m structure at room temperature. Detailed structural analyses, enabled by synchrotron-based experiments, coupled with ionic conductivity and thermal expansion studies enable the establishment of preliminary material-specific structure-property relationships that allow for the overall suitability of these materials as SOFC electrolytes to be assessed. REFERENCES: 1. Stambouli, A. B.; Traversa, E. Renew. Sustain. Energy Rev. 2002, 6, 433–455. 2. Ruiz-Morales, J. C.; Marrero-Lopez, D.; Galvez-Sanchez, M.; Canales-Vazquez, J.; Savaniu, C.; Savvin, S. N. Energy Environ. Sci. 2010, 3, 1670-1681. 3. Fergus, J. W. J. Power Sources. 2006, 162, 30–40. 4. Zuo, C.; Liu, M.; Liu, M. In Sol-Gel Processing for Conventional and Alternative Energy, eds. M. Aparicio et al. Springer Science+Business Media, New York, 2012; Chap. 2, pp 7-36. 5. Gomez, S. Y.; Hotza, D. Renew. Sustain. Energy Rev. 2016, 61, 155–174. 6. Fellet, M.; Rossner, W. MRS bulletin. 2015, 40, 214–215. 7. Minh, N. Q. Solid State Ion. 2004, 174, 271–277.

Primary author

Mr Mathias Kiefer (Wits University)


Dr Caren Billing (Wits University) Prof. David Billing (University of the Witwatersrand)

Presentation Materials