Arshad Muhammad S, Billing Caren, Billing David G, Guan Wanbing
Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Private Bag X3, Johannesburg 2050, South Africa.
Department of Chemical Sciences, University of Johannesburg, Doornfontein, Johannesburg 2028, South Africa.
ACS Appl Mater Interfaces. 2023 Aug 23;15(33):39396-39407. doi: 10.1021/acsami.3c08146. Epub 2023 Aug 9.
Efforts to lower the operating temperature of solid oxide fuel cells include producing electrolytes that are sufficiently conductive and stable below 600 °C. Doped ceria is one such electrolyte being considered. During this study, codoped ceria powders (CeSmMO, M = Bi, Zn and = 0, 0.05, 0.1, 0.15, 0.2) were prepared via coprecipitation by the addition of sodium carbonate and annealed at 800 and 1200 °C, respectively. Poor solubility of the codopants in the ceria was observed for samples annealed at 800 °C, resulting in a mixed-phase product including stable phases of the oxides of these codopants. A second-stage partial incorporation of these codopants into the ceria lattice was observed when the annealing temperature was increased to 1200 °C, with both codopants forming cubic-type phases of their respective oxides. Materials were characterized using X-ray diffraction (XRD), Raman spectroscopy, and Fourier transform infrared spectroscopy (FTIR), as well as scanning electron microscopy (SEM) for structural and morphological investigations. The oxide ion conductivity was evaluated using electrochemical impedance spectroscopy between 550 and 750 °C. Fuel cell performance tests of selected samples (annealed at 1200 °C) showed remarkable improvement in peak power densities when the test temperature was increased from 500 to 600 °C (∼720 mW/cm for CeSmBiO and ∼1230 mW/cm for CeSmZnO), indicating possible contribution from the distinct cubic-type oxide phases of the codopants in performance enhancement.
降低固体氧化物燃料电池工作温度的努力包括生产在600℃以下具有足够导电性和稳定性的电解质。掺杂二氧化铈就是其中一种正在被研究的电解质。在本研究中，通过添加碳酸钠共沉淀法制备了共掺杂二氧化铈粉末（CeSmMO，M = Bi、Zn， = 0、0.05、0.1、0.15、0.2），并分别在800℃和1200℃下进行退火。对于在800℃退火的样品，观察到共掺杂剂在二氧化铈中的溶解度较差，导致产物为混合相，包括这些共掺杂剂氧化物的稳定相。当退火温度提高到1200℃时，观察到这些共掺杂剂的第二阶段部分掺入二氧化铈晶格中，两种共掺杂剂均形成各自氧化物的立方型相。使用X射线衍射（XRD）、拉曼光谱、傅里叶变换红外光谱（FTIR）以及扫描电子显微镜（SEM）对材料进行表征，以进行结构和形态研究。在550℃至750℃之间使用电化学阻抗谱评估氧化物离子电导率。对选定样品（在1200℃退火）进行的燃料电池性能测试表明，当测试温度从500℃提高到600℃时，峰值功率密度有显著提高（CeSmBiO约为720 mW/cm²，CeSmZnO约为1230 mW/cm²），这表明共掺杂剂独特的立方型氧化物相对性能增强可能有贡献。
