La(Ni,Fe)O3 Stability in the Presence of Cr Species - solid-state Reactivity Study

The solid-state reactivity between La(Ni0.6Fe0.4)O3 (LNF) and Cr2O3 in the IT-SOFC operating temperature range of 600-800 ºC has been investigated using XRD analysis. Because LNF material can be used as a cathode, as a current collecting layer and/or an interconnect coating, a thorough investigation of its chemical stability is of importance for SOFC systems utilizing ferritic stainless steel interconnects. This study demonstrates the intrinsic instability of LNF when exposed to direct contact with Cr2O3 at 800 ºC. It has been observed that Cr enters the perovskite phase, replacing first Ni and then Fe already after 200 h. The rate of the Cr reaction with LNF depends on temperature and exposure time. After 1000 h at 600 ºC no reaction products could be detected with XRD. Although this is a promising result, long-term testing under fuel cell operating conditions is needed to prove LNF as a viable IT-SOFC cathode material.