Li Zhongqiu, Guan Bo, Xia Fang, Nie Jiuyuan, Li Wenyuan, Ma Liang, Li Wei, Zhou Lingfeng, Wang Yi, Tian Hanchen, Luo Jian, Chen Yan, Frost Matthew, An Ke, Liu Xingbo
Mechanical & Aerospace Engineering Department, West Virginia University, Morgantown, West Virginia 26506, United States.
School of Physics & Electronic Engineering, Harbin Normal University, Harbin 150025, China.
ACS Appl Mater Interfaces. 2022 Jun 1;14(21):24363-24373. doi: 10.1021/acsami.2c03657. Epub 2022 May 16.
To achieve chromium tolerance and high performance, a new series of high-entropy perovskites (HEPs) are investigated as cathode materials for solid oxide fuel cells (SOFCs). Multiple rare-earth, alkaline-earth, and high-order transition metal elements are used for the A-site of this ABO structure. A pure phase is achieved through the designed combination of different elements in seven out of eight candidates. Due to the retaining of alkaline-earth elements Sr and/or Ba, the electrical conductivities of these HEPs are in the order of 100 S/cm at 550-700 °C, a value that can practically eliminate the electronic resistance of the porous cathode. Three out of eight candidates show similar or better performance than the (LaSr)(CoFe)O (LSCF) benchmark. It is found that A-site elements can cast a substantial influence on the overall performance even with a change as small as 10% of the total cations. It seems that each element has its individual "phenomenal activity" that can be transferred from one candidate to the other in the general setting of the perovskite structure, leading to the best candidate by using the three most active elements simultaneously at the A-site. Excellent Cr tolerance has been observed on the (LaSrPrYBa)CoFeO sample, showing degradation of only 0.25%/kh during a 41 day operation in the presence of Cr, while LSCF increases by 100% within the first day in the same condition. X-ray photoelectron spectroscopy discovers no Sr segregation as LSCF is found in this HEP; rather, the active element Y takes more A-sites on the outermost layer after long-term operation.
为了实现耐铬性和高性能，研究了一系列新型高熵钙钛矿（HEPs）作为固体氧化物燃料电池（SOFCs）的阴极材料。在这种ABO结构的A位使用了多种稀土、碱土和高阶过渡金属元素。通过对八个候选材料中不同元素的设计组合，实现了纯相。由于保留了碱土元素Sr和/或Ba，这些HEPs在550-700°C时的电导率约为100 S/cm，该值实际上可以消除多孔阴极的电子电阻。八个候选材料中有三个表现出与（LaSr）（CoFe）O（LSCF）基准相似或更好的性能。研究发现，即使A位元素的变化仅占总阳离子的10%，也会对整体性能产生重大影响。似乎每个元素都有其独特的“显著活性”，在钙钛矿结构的一般情况下，这种活性可以从一个候选材料转移到另一个候选材料，通过在A位同时使用三种最具活性的元素来得到最佳候选材料。在（LaSrPrYBa）CoFeO样品上观察到了优异的耐铬性，在有Cr存在的情况下进行41天运行期间，降解率仅为0.25%/kh，而在相同条件下，LSCF在第一天内增加了100%。X射线光电子能谱发现，在这种HEPs中没有发现LSCF中那样的Sr偏析；相反，在长期运行后，活性元素Y在最外层占据了更多的A位。
