New Insights into the Degradation Behavior of Air Electrodes during Solid Oxide Electrolysis and Reversible Solid Oxide Cell Operation

Abstract

The commercialization of reversible solid oxide cells (RSOCs) is limited by the severe degradation of the air electrodes during solid oxide electrolysis cells (SOECs) operation. Herein, the degradation behavior of (La0.8Sr0.2)0.95Mn1−xCoxO3−δ (LSMC) air electrodes where x = 0.1, 0.3, and 0.5 is reported. After the SOEC test, the air electrode with x = 0.1 delaminates. While previous studies reported delamination due to the disintegration of air electrodes, for the first time, it is shown that delamination can also occur due to the disintegration of the samaria‐doped ceria (SDC) barrier layer into nanoparticles. The formation of such nanoparticles weakens the contact between the air electrode and barrier layer and encourages delamination. The air electrode with x = 0.3, shows excellent long‐term stability and also produces an electrolysis current density of 0.63 A cm−2 in 50% H2O/50% H2 at 1.3 V. This mechanistic study will allow researchers to develop air electrodes with improved long‐term stability.