Kim, Jeonghee Ji, Ho-Ii Dasari, Hari Prasad Shin, Dongwook Song, Huesup Lee, Jong-Ho Kim, Byung-Kook Je, Hae-June Lee, Hae-Weon Yoon, Kyung Joong 2024-01-20T13:01:50Z 2024-01-20T13:01:50Z 2021-09-01 2013-02-06 0360-3199 https://pubs.kist.re.kr/handle/201004/128362 Degradation mechanism of the electrolyte and air electrode is reported for solid oxide electrolysis cells (SOECs). Symmetric cells composed of yttria-stabilized zirconia (YSZ) electrolyte, Sr-doped LaMnO3 +/-delta (LSM)/YSZ composite working and counter electrodes, and Pt ring-type reference electrode are used to simulate the operating conditions of the air electrode. Degradation behavior in the impedance spectra is characterized as growth of mid-frequency arc at the initial stage, gradual increase of ohmic resistance throughout the operation, and sharp rise of low frequency resistance at the final stage, followed by catastrophic cell failure. Initial stage degradation is attributed to deactivation of LSM, resulting from reduction of oxygen vacancy concentration and/or segregation of passivation species on LSM surface under anodic current passage. Intergranular fracture, which occurs along the grain boundaries of the YSZ electrolyte, is responsible for gradual increase of ohmic resistance. Increase of low frequency arc at the final stage is caused by densification of the air electrode, leading to excessive pressure build-up and delamination of the air electrode. Cation migration, which is facilitated by oxygen excess nonstoichiometry of LSM and externally applied electric field, is considered to be the main cause of permanent damages. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. English PERGAMON-ELSEVIER SCIENCE LTD HIGH-TEMPERATURE ELECTROLYSIS DEMIXING PROFILE CALCULATION ELECTROCHEMICAL PERFORMANCE INTERMEDIATE-TEMPERATURE IMPEDANCE SPECTROSCOPY CATHODIC POLARIZATION STABILIZED ZIRCONIA HYDROGEN-PRODUCTION OXYGEN REDUCTION WATER-VAPOR Degradation mechanism of electrolyte and air electrode in solid oxide electrolysis cells operating at high polarization Article 10.1016/j.ijhydene.2012.10.113 1 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, v.38, no.3, pp.1225 - 1235 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 38 3 1225 1235 scie scopus 000315430600002 2-s2.0-84872296755 Chemistry, Physical Electrochemistry Energy & Fuels Chemistry Electrochemistry Energy & Fuels Article HIGH-TEMPERATURE ELECTROLYSIS DEMIXING PROFILE CALCULATION ELECTROCHEMICAL PERFORMANCE INTERMEDIATE-TEMPERATURE IMPEDANCE SPECTROSCOPY CATHODIC POLARIZATION STABILIZED ZIRCONIA HYDROGEN-PRODUCTION OXYGEN REDUCTION WATER-VAPOR Solid oxide electrolyzer Impedance spectroscopy Anodic current Degradation Densification