浸渍Gd_(0.2)Ce_(0.8)O_(1.9)对固体氧化物燃料电池La_(0.8)Sr_(0.2)Co_(0.2)Fe_(0.8)O_(3-δ)阴极铬中毒影响的研究

Effect of Gd_(0.2)Ce_(0.8)O_(1.9) Immersion on Chromium Poisoning Behavior of La_(0.8)Sr_(0.2)Co_(0.2)Fe_(0.8)O_(3-δ) Cathode of Solid Oxide Fuel Cells

固体氧化物燃料电池连接体中存在铬元素,会对阴极材料产生毒化作用,严重影响了阴极的电化学性能。采用浸渍法制备了用于固体氧化物燃料电池的La_(0.8)Sr_(0.2)Co_(0.2)Fe_(0.8)O_(3-δ)(LSCF)-Gd_(0.2)Ce_(0.8)O_(1.9)(GDC)复合阴极,以电化学测试为基础,结合扫描电子显微镜、电感耦合等离子光谱、X射线光电子能谱等分析表征方法考察了浸渍GDC对缓解LSCF阴极铬中毒的作用。结果表明,浸渍GDC不仅能提升LSCF阴极的电化学性能,而且对阴极铬中毒有一定程度的抑制作用。相对于LSCF阴极,LSCF-GDC复合阴极在含铬气氛中极化120 h后的电化学性能衰减程度降低。表征结果显示GDC会在阴极上形成包覆层,减少Cr元素与Sr元素的接触,使阴极上SrCrO_(4)的生成量变少,从而抑制LSCF阴极的Cr中毒。

The presence of chromium in the interconnector of solid oxide fuel cells poisons the cathode material and seriously damages electrochemical performance of the cathode.La_(0.8)Sr_(0.2)Co_(0.2)Fe_(0.8)O_(3-δ)(LSCF)-Gd_(0.2)Ce_(0.8)O_(1.9)(GDC)composite cathode was prepared by using an impregnation method.The effect of GDC on chromium poisoning behavior of the LSCF cathode was studied by using scanning electron microscopy(SEM),inductively coupled plasma spectroscop y(ICP-MS)and X-ray photoelectron spectroscopy(XPS).The impregnations with GDC can not only improve electrochemical performance of the LSCF cathode,but also inhibit the chromium poisoning of the cathode to a certain extent.Compared with the pristine LSCF cathode,the LSCF-GDC composite cathode exhibited lower degradation in electrochemical performance after polarization for 120 h in a chromium-containing atmosphere.The GDC formed a coating layer on the cathode to reduce the contact between Cr and Sr,thus preventing the formation of SrCrO_(4) and the Cr poisoning of the LSCF cathode.