基于纳米CT技术研究运行后Ni-YSZ阳极三维微结构变化  

Analysis of three-dimensional microstructure evolution of tested Ni-YSZ anodes by Nano-CT

作　　者：郭鹏飞[1] 关勇[1] 刘刚[1] 田扬超[1] 

机构地区：[1]中国科学技术大学国家同步辐射实验室,合肥230029

出　　处：《核技术》2016年第6期9-14,共6页Nuclear Techniques

基　　金：国家自然科学基金(No.11275204;No.11475175;No.11405175;No.11205189);国家重点基础研究发展计划(973计划)(No.2012CB825804)资助~~

摘　　要：固体氧化物燃料电池(Solid Oxide Fuel Cell,SOFC)阳极不仅提供了电化学反应的三相界面(Three-phase boundary,TPB)区域,而且在物质传输、扩散和燃料电池反应中不同物质之间的隔离起到积极作用。在运行期间,电极微结构发生变化。对SOFC阳极微结构演变的研究能够帮助我们理解长期运行的SOFC性能损失的原因。近年来不断发展的X射线纳米CT(Computed Tomography)技术使得可以无损地获得测试前后的阳极三维微结构。本文利用硬X射线纳米CT技术对Ni-YSZ复合阳极进行了三维重建,并采用自主开发的一些定量分析方法来获得阳极微结构的关键参数,如颗粒尺寸、每种相的体积分数和连通率等。发现在电池测试后,Ni颗粒尺寸增大,与之相对是由于Ni颗粒的聚集导致Ni相的连通性和三相界面长度明显下降。结果表明,在电池测试过程,Ni颗粒发生了团聚,电极微结构发生了改变,进而导致SOFC性能损失。阳极结构的数据表明,X射线纳米CT技术能够作为一个强力工具研究能源材料的微结构,为阳极结构优化提供重要参考数据。Background： Anode in solid oxide fuel cell （SOFC） provides three-phase boundary （TPB） regions for electrochemical reactions and plays an active role in mass transfer, gas diffusion and isolation between different substances. Purpose： During operation, the microstructure of anode will be changed. Research on microstmctural evolution of SOFC anode can help us understand performance degradation of SOFC after long time operation. Methods： Recently, development of X-ray nano-CT （Computed Tomography） makes it possible to nondestructively obtain the three-dimensional （3D） microstructural change of anodes subjected to no test and test for 20 h. Some quantitative analysis methods developed in house are applied to obtain key parameters of microstructures. Results： Based on the reconstructions of anode 3D microstructures, some parameters of microstructures are measured, such as particle size, volume fraction of each phase and connectivity for each phase. The average particle size of Ni increases after SOFC test, while the Ni-phase connectivity and TPB density of tested anode decrease, which is caused by the aggregation and growth of Ni particles. Conclusion： The data of untested and tested anode microstructures shows thatthe agglomeration of Ni particles occurs and internal structure of anode has changed after SOFC test, which may be a main reason causing performance degradation of SOFC during long time operation. This shows that X-ray nano-CT is a powerful tool to study energy materials and provides important data for optimizing the microstrncture of anode.

关 键 词：X射线成像 复合阳极 三维结构 连通性 

分 类 号：O434.19[机械工程—光学工程]