Bonding State and Thermal Expansion Coefficient of Mn-Doped Ba<sub>0.5</sub>Sr<sub>0.5</sub>FeO<sub>3−δ</sub> Perovskite Oxides for IT-SOFCs
The oxygen vacancy formation behavior and electrochemical and thermal properties of Ba<sub>0.5</sub>Sr<sub>0.5</sub>Fe<sub>1−x</sub>Mn<sub>x</sub>O<sub>3−δ</sub> (BSFMnx, x = 0–0.15) cathode materials were investigated. For thermogravimetri...
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MDPI AG
2023-12-01
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author | Taeheun Lim Sung-sin Yun Kanghee Jo Heesoo Lee |
author_facet | Taeheun Lim Sung-sin Yun Kanghee Jo Heesoo Lee |
author_sort | Taeheun Lim |
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description | The oxygen vacancy formation behavior and electrochemical and thermal properties of Ba<sub>0.5</sub>Sr<sub>0.5</sub>Fe<sub>1−x</sub>Mn<sub>x</sub>O<sub>3−δ</sub> (BSFMnx, x = 0–0.15) cathode materials were investigated. For thermogravimetric analysis, the weight decreased from 1.98% (x = 0) to 1.81% (x = 0.15) in the 400–950 °C range, which was due to oxygen loss from the lattice. The average oxidation state of the B-site increased, the O<sub>ads</sub>/O<sub>lat</sub> ratio decreased, and the binding energy of the O<sub>lat</sub> peak increased with Mn doping. These results indicate that Mn doping increases the strength of the metal–oxygen bond and decreases the amount of oxygen vacancies in the lattice. The electrical conductivity of BSFMnx increased with the temperature due to the thermally activated small-polaron hopping mechanism showing a maximum value of 10.4 S cm<sup>−1</sup> (x = 0.15) at 450 °C. The area-specific resistance of BSFMn0.15 was 0.14 Ω cm<sup>2</sup> at 700 °C and the thermal expansion coefficient (TEC) gradually decreased to 12.7 × 10<sup>−6</sup> K<sup>−1</sup>, which is similar to that of Ce<sub>0.8</sub>Sm<sub>0.2</sub>O<sub>2</sub> (SDC) (12.2 × 10<sup>−6</sup> K<sup>−1</sup>). Mn doping increased the metal–oxygen bonding energy, which reduced the oxygen reduction reaction activity but improved the electrical conductivity and thermal stability with SDC. |
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spelling | doaj.art-5155f0436cc44b0e92d32a2a7041dcae2024-01-10T15:05:02ZengMDPI AGNanomaterials2079-49912023-12-011418210.3390/nano14010082Bonding State and Thermal Expansion Coefficient of Mn-Doped Ba<sub>0.5</sub>Sr<sub>0.5</sub>FeO<sub>3−δ</sub> Perovskite Oxides for IT-SOFCsTaeheun Lim0Sung-sin Yun1Kanghee Jo2Heesoo Lee3School of Materials Science and Engineering, Pusan National University, Busan 46241, Republic of KoreaSchool of Materials Science and Engineering, Pusan National University, Busan 46241, Republic of KoreaSchool of Materials Science and Engineering, Pusan National University, Busan 46241, Republic of KoreaSchool of Materials Science and Engineering, Pusan National University, Busan 46241, Republic of KoreaThe oxygen vacancy formation behavior and electrochemical and thermal properties of Ba<sub>0.5</sub>Sr<sub>0.5</sub>Fe<sub>1−x</sub>Mn<sub>x</sub>O<sub>3−δ</sub> (BSFMnx, x = 0–0.15) cathode materials were investigated. For thermogravimetric analysis, the weight decreased from 1.98% (x = 0) to 1.81% (x = 0.15) in the 400–950 °C range, which was due to oxygen loss from the lattice. The average oxidation state of the B-site increased, the O<sub>ads</sub>/O<sub>lat</sub> ratio decreased, and the binding energy of the O<sub>lat</sub> peak increased with Mn doping. These results indicate that Mn doping increases the strength of the metal–oxygen bond and decreases the amount of oxygen vacancies in the lattice. The electrical conductivity of BSFMnx increased with the temperature due to the thermally activated small-polaron hopping mechanism showing a maximum value of 10.4 S cm<sup>−1</sup> (x = 0.15) at 450 °C. The area-specific resistance of BSFMn0.15 was 0.14 Ω cm<sup>2</sup> at 700 °C and the thermal expansion coefficient (TEC) gradually decreased to 12.7 × 10<sup>−6</sup> K<sup>−1</sup>, which is similar to that of Ce<sub>0.8</sub>Sm<sub>0.2</sub>O<sub>2</sub> (SDC) (12.2 × 10<sup>−6</sup> K<sup>−1</sup>). Mn doping increased the metal–oxygen bonding energy, which reduced the oxygen reduction reaction activity but improved the electrical conductivity and thermal stability with SDC.https://www.mdpi.com/2079-4991/14/1/82cobalt-free cathodeoxygen vacancyoxygen reduction reactionarea-specific resistancethermal expansion coefficient |
spellingShingle | Taeheun Lim Sung-sin Yun Kanghee Jo Heesoo Lee Bonding State and Thermal Expansion Coefficient of Mn-Doped Ba<sub>0.5</sub>Sr<sub>0.5</sub>FeO<sub>3−δ</sub> Perovskite Oxides for IT-SOFCs Nanomaterials cobalt-free cathode oxygen vacancy oxygen reduction reaction area-specific resistance thermal expansion coefficient |
title | Bonding State and Thermal Expansion Coefficient of Mn-Doped Ba<sub>0.5</sub>Sr<sub>0.5</sub>FeO<sub>3−δ</sub> Perovskite Oxides for IT-SOFCs |
title_full | Bonding State and Thermal Expansion Coefficient of Mn-Doped Ba<sub>0.5</sub>Sr<sub>0.5</sub>FeO<sub>3−δ</sub> Perovskite Oxides for IT-SOFCs |
title_fullStr | Bonding State and Thermal Expansion Coefficient of Mn-Doped Ba<sub>0.5</sub>Sr<sub>0.5</sub>FeO<sub>3−δ</sub> Perovskite Oxides for IT-SOFCs |
title_full_unstemmed | Bonding State and Thermal Expansion Coefficient of Mn-Doped Ba<sub>0.5</sub>Sr<sub>0.5</sub>FeO<sub>3−δ</sub> Perovskite Oxides for IT-SOFCs |
title_short | Bonding State and Thermal Expansion Coefficient of Mn-Doped Ba<sub>0.5</sub>Sr<sub>0.5</sub>FeO<sub>3−δ</sub> Perovskite Oxides for IT-SOFCs |
title_sort | bonding state and thermal expansion coefficient of mn doped ba sub 0 5 sub sr sub 0 5 sub feo sub 3 δ sub perovskite oxides for it sofcs |
topic | cobalt-free cathode oxygen vacancy oxygen reduction reaction area-specific resistance thermal expansion coefficient |
url | https://www.mdpi.com/2079-4991/14/1/82 |
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