Li_2O助烧的Gd_(0.1)Ce_(0.9)O_(1.95)烧结过程及其电导性能研究  

Sintering Behavior and Electrical Conductivity of Gd_(0.1)Ce_(0.9)O_(1.95) with Li_2O Additives

作　　者：杨志宾[1] 朱腾龙[1] 项文龙 于立安[1] 韩敏芳[1,2] 

机构地区：[1]中国矿业大学(北京)煤气化燃料电池中心,北京100083 [2]清华大学热能工程系,北京100084

出　　处：《无机材料学报》2015年第4期345-350,共6页Journal of Inorganic Materials

基　　金：国家科技部973项目(2012CB215404);中美自然科学基金国际合作项目(51261120378);北京市大学生科学研究与创业行动计划项目~~

摘　　要：氧化铈基电解质是中低温固体氧化物燃料电池最常用的材料之一。本研究利用密度泛函理论计算方法阐述了Li2O和Ce O2分子之间的相互作用,计算结果表明Li2O对Ce O2具有助烧作用。在此基础上,在氧化铈基电解质Gd0.1Ce0.9O1.95（GDC）中掺入不同比例（0~5mol%）Li2O,通过烧结曲线测试及扫描电镜分析了其实际烧结过程,并对其电化学性能进行了研究。实验结果表明,添加Li2O后,GDC的烧结开始收缩温度明显向低温偏移,随掺杂量的增加,最大收缩速率的温度也逐渐降低,其中掺入2.5mol%Li2O-GDC在650℃就开始迅速收缩,900℃时相对致密度在99%以上;添加Li2O后,GDC总电导率提高,同时电池开路电压没有降低。因此,Li2O是一种很好的燃料电池氧化铈基电解质的助烧剂,具有很好的应用前景。Cerium oxide-based materials are the most widely used electrolyte material for low-intermediate temperature Solid Oxide Fuel Cell（SOFC）. In this study, the interaction between Li2 O and Ce O2 was calculated based on density functional theory（DFT）. The results showed that the sintering of Ce O2 was positively affected by Li2 O. Based on this result, the actual sintering process of Gd0.1Ce0.9O1.95（GDC） with different concentration（0–5mol%） of Li2 O additive was characterized through the sintering behavior and scanning electron microscope（SEM）. The electrochemical performance was also being investigated simultaneously. The results show that the initial shrinkage temperature shifted to lower temperature significantly, and the temperature of the highest shrinkage rate also decreased with the increasing of the Li2 O additive content. The shrinking of GDC with 2.5mol% Li2 O started at 650 ℃, and the GDC electrolyte with higher than 99% relative density was obtained at a low sintering temperature of 900 ℃. The total electrical conductivity of GDC was improved with Li2 O additive. Meanwhile, the open circuit voltage of the corresponding single cell maintained nearly the same with pure GDC. These preliminary results indicate that Li2 O is a very effective sintering aid for cerium oxide-based electrolyte in SOFC.

关 键 词：氧化铈基电解质 烧结助剂 固体氧化物燃料电池 

分 类 号：TQ174[化学工程—陶瓷工业]