A位缺陷对铁酸盐基阴极材料硫中毒特性影响

Effect of A-Site Defect on Sulfur Poisoning Behaivor of Ferrite-Based Cathode Materials

空气中微量SO_(2)(10-9)引起阴极材料硫中毒是导致固体氧化物燃料电池(SOFC)性能衰减的关键因素之一。将(La_(0.6)Sr_(0.4))(Co_(0.2)Fe_(0.8))O_(3)(LSCF)和A位缺陷型(La_(0.6) Sr_(0.4))_(0.8)5(Co_(0.2)Fe_(0.8))O_(3)(LSCF85)样品放置在含有30μg/gSO_(2)的干空气气氛中,800℃条件下热处理50 h后,对反应的生成物进行XRD、SEM、EDX表征,评价A位缺陷的存在对钙钛矿结构铁酸盐基固体氧化物燃料电池阴极材料硫中毒行为的影响。结果发现,对于钙钛矿结构LSCF阴极材料,A位缺陷的引入可以有效地抑制该材料与SO_(2)发生化学反应生成SrSO_(4),提高材料在含SO_(2)气氛中的化学稳定性。其原因可能是由于A位缺陷的引入,降低了LSCF中Sr元素的活性,从而抑制了Sr元素与SO_(2)之间化学反应的发生。

Ppb amount of SO_(2) in air will react with cathode material of solid oxide fuel cell,inducing decrease of the cell/stack performance as one of the most effective factors.The sulfur poisoning behavior of(La_(0.6)Sr_(0.4))(Co_(0.2)Fe_(0.8))O_(3)(LSCF)and A-site deficient(La_(0.6)Sr_(0.4))_(0.8)5(Co_(0.2)Fe_(0.8))O_(3)(LSCF85)was investigated after exposure to 30μg/g SO_(2) at 800℃for 50 h.The products of the reaction were characterized by XRD,SEM and EDX to evaluate the effect of A-site defects on the sulfur poisoning behavior of perovskite ferrite based solid oxide fuel cell cathode materials.It was found that A-site defect in LSCF85 can suppress the chemical reaction between LSCF based cathode and SO_(2).It was ascribed to the low Sr reaction activity with SO_(2) caused by the existence of A-site defect.