The surface evolution of La0.4Sr0.6TiO3+δ anode in solid oxide fuel cells: Understanding the sulfur-promotion effect

JOURNAL OF POWER SOURCES

卷:343

Article

Yan, Ning^1,2  Zanna, Sandrine³  Klein, Lorena H.³  Roushanafshar, Milad¹  Amirkhiz, Babak S.⁴  Zeng, Yimin⁴  Rothenberg, Gadi²  Marcus, Philippe³  Luo, Jing-Li¹ 

[1] Univ Alberta, Dept Chem & Mat Engn, Edmonton, AB T6G 1H9, Canada

[2] Univ Amsterdam, Vant Hoff Inst Mol Sci HIMS, NL-1098 XH Amsterdam, Netherlands

[3] PSL Res Univ, Res Grp Phys Chem Surfaces, Inst Rech Chim Paris, Chim ParisTech,CNRS, 11 Rue Pierre & Marie Curie, F-75005 Paris, France

[4] Nat Resources Canada, CanmetMAT, Hamilton, ON L8P 0A5, Canada

关键词: Titanate;    Sulfur poisoning;    Sulfur promoter;    Surface chemistry;    Quenching;   

DOI  :  10.1016/j.jpowsour.2017.01.048

来源: Elsevier

【 摘 要 】

The ideal solid oxide fuel cells (SOFCs) can be powered by readily available hydrocarbon fuels containing impurities. While this is commonly recognized as a key advantage of SOFC, it also, together with the elevated operating temperature, becomes the main barrier impeding the in-situ or operando investigations of the anode surface chemistry. Here, using a well-designed quenching experiment, we managed to characterize the near-surface structure of La0.4Sr0.6TiO3+delta (LST) anode in SOFCs fuelled by H2S-containing methane. This new method enabled us to clearly observe the surface amorphization and sulfidation of LST under simulated SOFC operating conditions. The similar to 1 nm-thick two dimensional sulfur adsorbed layer was on top of the disordered LST, containing -S, -SH and elemental sulfur species. In SOFC test, such poisoned anode showed increased performances: a ten-fold enhanced power density enhancement (up to 30 mW cm(-2)) and an improved open circuit voltage (from 0.69 V to 1.17 V). Moreover, its anodic polarization resistance in methane decreased to 21.53 cm(2), a difference of 95% compared with the sulfur-free anode. Control experiments confirmed that once the adsorbed sulfur species were removed electrochemically, methane conversion slowed down simultaneously till full stop. (C) 2017 Elsevier B.V. All rights reserved.

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