Koo, Ja Yang Kwon, Hyunguk Ahn, Minwoo Choi, Mingi Son, Ji-Won Han, Jeong Woo Lee, Wonyoung 2024-01-19T23:04:15Z 2024-01-19T23:04:15Z 2021-09-03 2018-03-07 1944-8244 https://pubs.kist.re.kr/handle/201004/121612 Strontium segregation at perovskite surfaces deteriorates the oxygen reduction reaction kinetics of cathodes and therefore the long-term stability of solid oxide fuel cells (SOFCs). For the systematic and quantitative assessment of the elastic energy in perovskite oxides, which is known to be one of the main origins for dopant segregation, we report the fractional free volume as a new descriptor for the elastic energy in the perovskite oxide system. To verify the fractional free volume model, three samples were prepared with different A-site dopants: La0.6Sr0.4CoO3-delta, La0.6Sr0.2Ca0.2CoO3-delta, and La0.6Ca0.4CoO3-delta. A combination of the theoretical calculations of the segregation energy and oxide formation energy and experimental measurements of the structural, chemical, and electrochemical degradation substantiated the validity of using the fractional free volume to predict the dopant segregation. Furthermore, the dopant segregation could be significantly suppressed by increasing the fractional free volume in the perovskite oxides with dopant substitution. Our results provide insight into dopant segregation from the elastic energy perspective and offer a design guideline for SOFC cathodes with enhanced stability at elevated temperatures. English American Chemical Society OXIDE FUEL-CELLS THIN-FILMS PEROVSKITE OXIDES SURFACE PERFORMANCE STABILITY TEMPERATURE REDUCTION ELECTROLYTES DEGRADATION Suppression of Cation Segregation in (La,Sr)CoO3-delta, by Elastic Energy Minimization Article 10.1021/acsami.7b19390 1 ACS Applied Materials & Interfaces, v.10, no.9, pp.8057 - 8065 ACS Applied Materials & Interfaces 10 9 8057 8065 scie scopus 000427204100057 2-s2.0-85043342531 Nanoscience & Nanotechnology Materials Science, Multidisciplinary Science & Technology - Other Topics Materials Science Article OXIDE FUEL-CELLS THIN-FILMS PEROVSKITE OXIDES SURFACE PERFORMANCE STABILITY TEMPERATURE REDUCTION ELECTROLYTES DEGRADATION solid oxide fuel cells perovskite dopant segregation elastic energy long-term stability