Mechanism of improved electrochemical performance of anode-supported solid oxide fuel cells by mesostructural modification of electrode-electrolyte interface
Mechanism of improved electrochemical performance of anode-supported solid oxide fuel cells by mesostructural modification of electrode-electrolyte interface
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DOI：
10.1016/j.jpowsour.2021.230107
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发表时间：
2021-06-05
影响因子：
9.2
通讯作者：
Yoshida, Hideo
中科院分区：
文献类型：
--
作者：
Seo, Haewon;Kishimoto, Masashi;Yoshida, Hideo
阐明了介观尺度（10-100 μ m）结构修饰改善阳极支撑固体氧化物燃料电池（SOFC）电化学性能的机理。制备了两种具有不同电极-电解质界面面积的阳极支撑SOFC，并对其进行了结构分析和电化学表征。接下来，我们开发了一个二维（2D）的数值模型，在其中实现的细胞的结构，然后通过比较实验和仿真结果验证其有效性。结果发现，在介观修饰的细胞，如界面面积扩大和厚度的不均匀性的结构特征，导致非均匀分布的物理化学量，有助于电化学反应。因此，在欧姆和活化过电位的介观修饰的电池相对于扁平电池的减少分别大于和小于那些估计的假设下，离子和电荷转移电流密度均匀分布在一个单元。此外，在高电流密度下，离子电流密度分布具有很强的不均匀性，导致欧姆损耗的较大相对降低。此外，电池过电位在较高的电流密度下降低得更多;因此，阳极支撑的SOFC的介观结构修饰可以导致更高的电池性能。
The mechanism whereby structural modification on the mesoscale order (10-100 mu m) improves the electrochemical performance of anode-supported solid oxide fuel cells (SOFCs) is elucidated. After preparing two types of anode-supported SOFC having different electrode-electrolyte interfacial areas, we carry out their structural analyses and electrochemical characterization. Next, we develop a two-dimensional (2D) numerical model in which the structures of the cells are implemented and then verify its validity by comparing experimental and simulation results. It is found that the structural features in the mesoscale-modified cell, such as interfacial area enlargement and thickness inhomogeneity, cause nonuniform distributions of physicochemical quantities that contribute to electrochemical reactions. Consequently, the decreases in the ohmic and activation overpotentials of the mesoscale-modified cell relative to the flat cell are respectively larger and smaller than those estimated under the assumptions that the ionic and charge-transfer current densities are uniformly distributed in a cell. Moreover, the ionic current density distribution has a strong nonuniformity at a high current density, leading to a large relative decrease in ohmic loss. Furthermore, the cell overpotential is more reduced at a higher current density; thus, the mesostructural modification of anode-supported SOFCs can lead to a higher cell performance.