HU Xingguo, LIU Limin, QIAN Xinyuan, HE Feifan, WANG Zhou, CHEN Hanyu, SHENG Yang, ZHOU Xiaoliang
(College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610000, Sichuan, China)
Abstract: Solid oxide cells (SOCs) with Ni-YSZ fuel electrodes were prepared by using cast-screen printing method. Highly catalytically active materials, including Ce0.9Fe0.1Mn0.3O 2−6 (CFO), Ce0.9Fe0.1Mn0.3O 2−6 (CMO) and Ce0.6Fe0.1Mn0.3O 2−6 (CFM), were prepared by using Fe/Mn doped CeO2 , which were then impregnated to modify the Ni-YSZ electrodes. Microstructure, properties and stability of the electrodes after impregnation modification were studied, with electrochemical tests combined with analytical characterization methods, such as scanning electron microscopy (SEM), X-ray diffractometer (XRD) and energy spectrometer. The highest power densities of the unimpregnated, CFO, CMO and CFM impregnation modified Ni-YSZ electrodes in H2 (3 vol.% H2O) at 850 °C were 526 mW ·cm−2 , 724 mW ·cm−2 , 706 mW ·cm−2 and 829 mW ·cm−2 , respectively, while the electrolytic current densities in VCO2:VCO=50:50 at 850 ℃ at 1.8 V were 0.55 A ·cm−2 , 1.39 A ·cm−2 , 1.43 A ·cm−2 and 1.63 A ·cm一2 , respectively. Obviously, the performance was significantly improved after the impregnation modification, with CFM to be the best modification agent. The CFM-impregnated Ni-YSZ electrode was characterized by using CO2 electrolytic stability test and EDS element content analysis. The decay rate was only 3.7% after testing for 100 h and the C content was almost unchanged before and after the testing, indicating that the CFM-impregnated Ni-YSZ electrode has high stability and can suppress the generation of carbon deposition. Therefore, CFO, CMO, and CFM are promising impregnation modifiers to extend the length of the three-phase boundary (TPB), optimize the microstructure and improve catalytic activity and stability of the Ni-YSZ electrode.
Key words: SOCs; Ni-YSZ electrode; transition metal; CeO2 ; impregnation modified