固体氧化物燃料电池模式阳极内传输与电化学反应耦合机理  

Coupling mechanism of mass transport and electrochemical reaction within patterned anode of solid oxide fuel cell

作　　者：徐晗[1] 张璐[1] 党政[1] Xu Han;Zhang Lu;Dang Zheng(Department of Building Environment and Energy Engineering,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]西安交通大学建筑环境与能源应用工程系,西安710049

出　　处：《物理学报》2020年第9期280-288,共9页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:51606151)资助的课题.

摘　　要：模式电极因其结构可控、电化学/化学反应活性位和物质传输路径明确等优势,被广泛应用于固体氧化物燃料电池新型电极研究.现有研究多采用模式电极研究新材料电化学特性、表界面催化反应机理等,尚未涉及几何结构对其内部传输与电化学反应耦合机理的影响,限制了模式电极的应用.本文建立了固体氧化物燃料电池阳极内电荷传输与电化学反应过程的格子玻尔兹曼模拟方法,明确了控制电极过程的关键无量纲参数及其对电极性能的影响规律,研究了模式阳极几何结构的影响机理.根据电极性能对无量纲参数的敏感程度,绘制了指导模式阳极设计与运行的相图,指出相图过渡区(电极性能随操作参数显著变化区域)为进行反应机理研究的最佳操作参数取值范围.同时,研究发现模式阳极电子导体内电子的快速迁移虽不限制阳极性能,其几何结构显著影响过渡区范围;离子导体内离子迁移为影响阳极性能的限速步骤,但其几何结构几乎不影响过渡区范围.本文的数值方法与机理研究结果可为固体氧化物燃料电池模式电极的设计提供重要理论依据.Patterned electrodes are widely used in the development of novel electrodes of solid oxide fuel cells(SOFCs) because of their well-controlled geometries, distinguishable catalytically active sites and simple transport paths. In the existing studies the patterned electrodes are usually adopted to reveal relevant reaction mechanisms and to investigate the electrochemical characteristics of new materials of SOFCs, however, the effects of electrode geometry are not taken into consideration. In the present paper, a lattice Boltzmann model for simulating the charge transport and electrochemical reaction in an SOFC patterned anode is established,and the key dimensionless parameters governing the above electrode process are deduced. This model is then used to investigate the effects of the key dimensionless parameters on the electrochemical performance of a patterned anode. More importantly, the influences of the patterned anode geometry on the coupling of the charge transport and electrochemical reaction are unraveled. According to the sensitivity of the electrode performance to the dimensionless parameters, a dimensionless phase map, which is divided into maximum area,transition area and minimum area, is built. It is concluded that the transition area, in which the electrode performance varies dramatically with the parameters of design and operation, is regarded as the optimal range for studying the relevant reaction mechanism. Meanwhile, it is found that although the electron transport does not restrict the electrode performance, the moderate decrease of the height-to-width ratio of electronic conductor is capable of enlarging the transition area, which is beneficial to revealing the relevant reaction mechanism. Conversely, the ion transport is the rate-limiting step, however, the transition area remains unchanged under different ionic conductor geometries. The present numerical method and conclusions could offer guidance for rationally designing and operating the patterned electrodes.

关 键 词：固体氧化物燃料电池 模式阳极 相图 过渡区 

分 类 号：TM911.4[电气工程—电力电子与电力传动]