AUTHOR=Song Kyeong Eun , Woo Sung Hun , Baek Seung Wook , Kang Hyunil , Choi Won Seok , Park Jun Young , Kim Jung Hyun 

TITLE=SmBa1-xCaxCo2O5+d Layered Perovskite Cathodes for Intermediate Temperature-operating Solid Oxide Fuel Cells

JOURNAL=Frontiers in Chemistry

VOLUME=8

YEAR=2021

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2020.628813

DOI=10.3389/fchem.2020.628813

ISSN=2296-2646

ABSTRACT=<p>In SmBa<sub>1-x</sub>Ca<sub>x</sub>Co<sub>2</sub>O<sub>5+d</sub> (x = 0.01, 0.03, 0.1, and 0.2, SBCCO) oxide systems calcined at 1100°C for 8 h, the XRD patterns of the SBCCO single phase were maintained in the cases of SmBa<sub>0.97</sub>Ca<sub>0.03</sub>Co<sub>2</sub>O<sub>5+d</sub> (SBCCO-0.97) and SmBa<sub>0.99</sub>Ca<sub>0.01</sub>Co<sub>2</sub>O<sub>5+d</sub> (SBCCO-0.99) compositions. In SmBa<sub>0.8</sub>Ca<sub>0.2</sub>Co<sub>2</sub>O<sub>5+d</sub> (SBCCO-0.8) and SmBa<sub>0.9</sub>Ca<sub>0.1</sub>Co<sub>2</sub>O<sub>5+d</sub> (SBCCO-0.9), CaCoSmO<sub>4</sub> existed with the pattern SBCCO. SBCCO structures were identified as orthorhombic crystal structures because they showed splitting of the X-ray diffraction (XRD) peaks at 23.4°, 47.9°, and 59.1°.Typical metallic conduction behaviors were found in all measured compositions except SBCCO-0.8, which showed a metal-insulator transition (MIT) behavior. Compared to other SmBa<sub>1-x</sub>Ca<sub>x</sub>Co<sub>2</sub>O<sub>5+d</sub> compositions, SBCCO-0.8 showed the highest electrical conductivity of 460 S/cm at 500°C. In particular, SBCCO-0.9 was found to have an excellent ASR characteristic of about 0.077 Ωcm<sup>2</sup> at 700°C. The activation energy of SBCCO-0.9 was the lowest among SBCCO oxide systems with a value of 0.77 eV.</p>