CHEMICAL STABILITY OF DOPED δ-Bi2O3 AS AN ELECTROLYTE FOR SOLID OXIDE FUEL CELLS
Authors
Malešević, AleksandarDapčević, Aleksandra
Radojković, Aleksandar
Branković, Zorica
Branković, Goran
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The high temperature phase of bismuth oxide (δ-Bi2O3) is a promising material
for application as an electrolyte for solid oxide fuel cells (SOFCs), due to its high
oxygen ion conductivity. Doping with rare earth cations stabilizes δ-Bi2O3 phase
down to room temperature. According to literature [1], the ionic conductivity of
such δ-Bi2O3 is not significantly decreased even at 600 °C. This opens the
possibility to lower SOFC operating temperature from 1000 °C to intermediate
temperatures. The main drawbacks of this material are the instability in reducing
atmosphere and reactivity toward electrode materials. Bismuth ruthenate (Bi2Ru2O7)
was chosen as a potential electrode material because of its chemical stability,
compatibility with δ-Bi2O3 and metal-like electronic conductivity.
Stoichiometric mixtures of Bi2O3 with Tm2O3 or Lu2O3 were dry homogenized
and heat treated at 750 °C for 3 h in order to obtain δ-Bi2O3 with following
compositions: (Bi0.8Tm0.2)2O3 and (Bi0.75Lu0.25...)2O3, respectively. Bi2Ru2O7 was
synthesized similarly, i.e. homogenized mixture of Bi2O3 and RuO2·xH2O was
heated at 900 °C for 3 h. The obtained powders were pressed into disc-shaped
pellets and sintered at 920 °C in case of δ-Bi2O3 and 880 °C in case of Bi2Ru2O7.
Chemical stability of these materials was investigated by exposing the pellets to the
hydrogen and butane atmospheres. Compatibility of electrode and electrolyte
materials was tested by heating a homogenized mixture of Bi2Ru2O7 and
(Bi0.8Tm0.2)2O3 (mass ratio 50:50) at 600 °C. Moreover, a mixture of
(Bi0.75Lu0.25)2O3 and Bi2Ru2O7 (mass ratio 30:70) was pressed into pellet, sintered at
880 °C, and exposed to hydrogen atmosphere in order to evaluate chemical stability
of the mixture under reducing conditions. Both electrolyte- and electrode-supported
configurations were considered with the aim to form a functional fuel cell.
1. A. Dapčević, D. Poleti, J. Rogan, A. Radojković, M. Radović, G. Branković, Solid
State Ionics, 280 (2015) 18
Keywords:
SOFC, electrolyte, Bi2O3, Bi2Ru2O7Source:
5th Conference of The Serbian Society for Ceramic Materials, Belgrade, Serbia, 2019, 81-Publisher:
- The Serbian Society for Ceramic Materials
Funding / projects:
- Zero- to Three-Dimensional Nanostructures for Application in Electronics and Renewable Energy Sources: Synthesis, Characterization and Processing (RS-MESTD-Integrated and Interdisciplinary Research (IIR or III)-45007)
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Institution/Community
Institut za multidisciplinarna istraživanjaTY - CONF AU - Malešević, Aleksandar AU - Dapčević, Aleksandra AU - Radojković, Aleksandar AU - Branković, Zorica AU - Branković, Goran PY - 2019 UR - http://rimsi.imsi.bg.ac.rs/handle/123456789/2293 AB - The high temperature phase of bismuth oxide (δ-Bi2O3) is a promising material for application as an electrolyte for solid oxide fuel cells (SOFCs), due to its high oxygen ion conductivity. Doping with rare earth cations stabilizes δ-Bi2O3 phase down to room temperature. According to literature [1], the ionic conductivity of such δ-Bi2O3 is not significantly decreased even at 600 °C. This opens the possibility to lower SOFC operating temperature from 1000 °C to intermediate temperatures. The main drawbacks of this material are the instability in reducing atmosphere and reactivity toward electrode materials. Bismuth ruthenate (Bi2Ru2O7) was chosen as a potential electrode material because of its chemical stability, compatibility with δ-Bi2O3 and metal-like electronic conductivity. Stoichiometric mixtures of Bi2O3 with Tm2O3 or Lu2O3 were dry homogenized and heat treated at 750 °C for 3 h in order to obtain δ-Bi2O3 with following compositions: (Bi0.8Tm0.2)2O3 and (Bi0.75Lu0.25)2O3, respectively. Bi2Ru2O7 was synthesized similarly, i.e. homogenized mixture of Bi2O3 and RuO2·xH2O was heated at 900 °C for 3 h. The obtained powders were pressed into disc-shaped pellets and sintered at 920 °C in case of δ-Bi2O3 and 880 °C in case of Bi2Ru2O7. Chemical stability of these materials was investigated by exposing the pellets to the hydrogen and butane atmospheres. Compatibility of electrode and electrolyte materials was tested by heating a homogenized mixture of Bi2Ru2O7 and (Bi0.8Tm0.2)2O3 (mass ratio 50:50) at 600 °C. Moreover, a mixture of (Bi0.75Lu0.25)2O3 and Bi2Ru2O7 (mass ratio 30:70) was pressed into pellet, sintered at 880 °C, and exposed to hydrogen atmosphere in order to evaluate chemical stability of the mixture under reducing conditions. Both electrolyte- and electrode-supported configurations were considered with the aim to form a functional fuel cell. 1. A. Dapčević, D. Poleti, J. Rogan, A. Radojković, M. Radović, G. Branković, Solid State Ionics, 280 (2015) 18 PB - The Serbian Society for Ceramic Materials C3 - 5th Conference of The Serbian Society for Ceramic Materials, Belgrade, Serbia T1 - CHEMICAL STABILITY OF DOPED δ-Bi2O3 AS AN ELECTROLYTE FOR SOLID OXIDE FUEL CELLS SP - 81 UR - https://hdl.handle.net/21.15107/rcub_rimsi_2293 ER -
@conference{ author = "Malešević, Aleksandar and Dapčević, Aleksandra and Radojković, Aleksandar and Branković, Zorica and Branković, Goran", year = "2019", abstract = "The high temperature phase of bismuth oxide (δ-Bi2O3) is a promising material for application as an electrolyte for solid oxide fuel cells (SOFCs), due to its high oxygen ion conductivity. Doping with rare earth cations stabilizes δ-Bi2O3 phase down to room temperature. According to literature [1], the ionic conductivity of such δ-Bi2O3 is not significantly decreased even at 600 °C. This opens the possibility to lower SOFC operating temperature from 1000 °C to intermediate temperatures. The main drawbacks of this material are the instability in reducing atmosphere and reactivity toward electrode materials. Bismuth ruthenate (Bi2Ru2O7) was chosen as a potential electrode material because of its chemical stability, compatibility with δ-Bi2O3 and metal-like electronic conductivity. Stoichiometric mixtures of Bi2O3 with Tm2O3 or Lu2O3 were dry homogenized and heat treated at 750 °C for 3 h in order to obtain δ-Bi2O3 with following compositions: (Bi0.8Tm0.2)2O3 and (Bi0.75Lu0.25)2O3, respectively. Bi2Ru2O7 was synthesized similarly, i.e. homogenized mixture of Bi2O3 and RuO2·xH2O was heated at 900 °C for 3 h. The obtained powders were pressed into disc-shaped pellets and sintered at 920 °C in case of δ-Bi2O3 and 880 °C in case of Bi2Ru2O7. Chemical stability of these materials was investigated by exposing the pellets to the hydrogen and butane atmospheres. Compatibility of electrode and electrolyte materials was tested by heating a homogenized mixture of Bi2Ru2O7 and (Bi0.8Tm0.2)2O3 (mass ratio 50:50) at 600 °C. Moreover, a mixture of (Bi0.75Lu0.25)2O3 and Bi2Ru2O7 (mass ratio 30:70) was pressed into pellet, sintered at 880 °C, and exposed to hydrogen atmosphere in order to evaluate chemical stability of the mixture under reducing conditions. Both electrolyte- and electrode-supported configurations were considered with the aim to form a functional fuel cell. 1. A. Dapčević, D. Poleti, J. Rogan, A. Radojković, M. Radović, G. Branković, Solid State Ionics, 280 (2015) 18", publisher = "The Serbian Society for Ceramic Materials", journal = "5th Conference of The Serbian Society for Ceramic Materials, Belgrade, Serbia", title = "CHEMICAL STABILITY OF DOPED δ-Bi2O3 AS AN ELECTROLYTE FOR SOLID OXIDE FUEL CELLS", pages = "81", url = "https://hdl.handle.net/21.15107/rcub_rimsi_2293" }
Malešević, A., Dapčević, A., Radojković, A., Branković, Z.,& Branković, G.. (2019). CHEMICAL STABILITY OF DOPED δ-Bi2O3 AS AN ELECTROLYTE FOR SOLID OXIDE FUEL CELLS. in 5th Conference of The Serbian Society for Ceramic Materials, Belgrade, Serbia The Serbian Society for Ceramic Materials., 81. https://hdl.handle.net/21.15107/rcub_rimsi_2293
Malešević A, Dapčević A, Radojković A, Branković Z, Branković G. CHEMICAL STABILITY OF DOPED δ-Bi2O3 AS AN ELECTROLYTE FOR SOLID OXIDE FUEL CELLS. in 5th Conference of The Serbian Society for Ceramic Materials, Belgrade, Serbia. 2019;:81. https://hdl.handle.net/21.15107/rcub_rimsi_2293 .
Malešević, Aleksandar, Dapčević, Aleksandra, Radojković, Aleksandar, Branković, Zorica, Branković, Goran, "CHEMICAL STABILITY OF DOPED δ-Bi2O3 AS AN ELECTROLYTE FOR SOLID OXIDE FUEL CELLS" in 5th Conference of The Serbian Society for Ceramic Materials, Belgrade, Serbia (2019):81, https://hdl.handle.net/21.15107/rcub_rimsi_2293 .