Systematic Study of Chromium Poisoning of LSM Cathodes - Single Cell Tests

Abstract

Chromium poisoning of solid oxide fuel cell cathodes is up to now considered as one major factor which limits life-time and is responsible for degradation. Still unclear are to which extend chromium poisoning is responsible and what the basic degradation mechanism is. At Forschungszentrum Jülich this ambiguity should be clarified by two ways: firstly the post-mortem analysis of cells operated within a stack and secondly by carrying out single cell tests with varied chromium releasing sources and operating conditions. This presentation summarizes the results of approximately 60 single cell tests. The experiments were carried out with variation of operation time, current density applied and the chromium source. The cells are characterized for their degree of degradation, for their chromium content and change in microstructure. The results show that cells solely degrade strongly when current density was applied and a strong chromium source was present and support an electrochemical interaction mechanism.