La(Ni,Fe)O_3 Stability in the Presence of Cr Species - Solid State Reactivity Study

摘要

The solid-state reactivity between La(Ni_(0.6)Fe_(0.4))O_3 (LNF) and Cr_2O_3 in the IT-SOFC operating temperature range of 600-800°C 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 Cr_2O_3 at 800°C. 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°C 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.