Oxygen reduction on strontium-doped LaMnO3 cathodes in the absence and presence of an iron–chromium alloy interconnect

Zhen, Y. D.; Li, Jian

doi:10.1016/j.jpowsour.2006.08.034

Cited by 38 publications

(17 citation statements)

References 56 publications

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“…The impedance responses to reactions on both electrodes are similar, which is characterised by an overlapped impedance arc with a low frequency inductance loop. The low frequency inductance loop was also observed for O 2 reduction reactions in LSM electrodes in the presence of chromium gaseous species and/or under dc bias [19,20] [21] and for methane and ethanol oxidation reactions in Pd-promoted (La, Sr)(Cr, Mn)O 3 (LSCM) anodes [15]. It seems that such a low frequency loop is often associated with reactions in nanostructured electrodes with a significantly high specific surface area; its appearance may be related to the adsorption and desorption of the reactant species on the electrode surface.…”

Section: Microstructure and Electrochemical Activity Of Pd-and Pd 09mentioning

confidence: 68%

Mn‐Stabilised Microstructure and Performance of Pd‐impregnated YSZ Cathode for Intermediate Temperature Solid Oxide Fuel Cells

et al. 2009

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The effect of Mn alloying on PdO powder and Pd‐impregnated Pd + YSZ cathode for the O2 reduction reaction in intermediate temperature solid oxide fuel cells has been studied in detail. The microstructure, thermal stability, electrochemical activity and performance stability of the powder and cathode were analysed using thermal gravimetric analysis, X‐ray diffraction, scanning electron microscopy/energy dispersive spectroscopy and electrochemical impedance spectroscopy. The results indicate that an addition of 5 mol.‐% Mn effectively inhibits the growth and coalescence of Pd and PdO particles at high temperatures and stabilises the microstructure of the powders and the electrode; as a consequence, the electrochemical performance and stability of the cathode are significantly improved. The electrochemical performance of the Pd + YSZ and Pd0.95Mn0.05 + YSZ cathodes so prepared is much better than that of the conventional LSM‐based cathodes and is also comparable with the mixed ionic and electronic conducting oxide cathodes such as LSCF.

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Section: Microstructure and Electrochemical Activity Of Pd-and Pd 09mentioning

confidence: 68%

Mn‐Stabilised Microstructure and Performance of Pd‐impregnated YSZ Cathode for Intermediate Temperature Solid Oxide Fuel Cells

et al. 2009

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“…There is a substantial reduction in the electrode impedance at low frequencies, and the impedance responses are characterized by a much smaller arc with a significant lowfrequency inductance loop. The low-frequency inductance loop was also reported for the O 2 reduction reaction in the presence of chromium gaseous species and for the reaction under dc bias on LSM electrodes 26,27 for the oxidation reaction of methane and ethanol on Pd-promoted ͑La,Sr͒͑Cr,Mn͒O 3 ͑LSCM͒ anodes. 28 As this lowfrequency loop is often seen for the reaction in nanostructured electrodes and in Pd-promoted cathodes and anodes, the low-frequency loop could be attributed to significant dissociation and adsorption of oxygen species on the electrode surface, enhanced by the nanostructure and the presence of catalytic promoter.…”

Section: B214mentioning

confidence: 83%

Development of Nanostructured and Palladium Promoted (La,Sr)MnO[sub 3]-Based Cathodes for Intermediate-Temperature SOFCs

Liang

Chen

Jiang

et al. 2008

Electrochem. Solid-State Lett.

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Nanostructured and palladium-promoted Sr-doped LaMnO 3 ͑LSM͒-based cathodes are developed via solution impregnation for intermediate-temperature solid oxide fuel cells ͑IT-SOFCs͒. Both the nanostructured and Pd-promoted LSM-based cathodes show significantly improved electrochemical performance compared to the conventional LSM/Y 2 O 3 -doped ZrO 2 YSZ composite cathode, with electrode polarization resistances of 1.5 and 0.9 ⍀ cm 2 at 600°C, respectively, in contrast to 70 ⍀ cm 2 obtained from the conventional LSM/YSZ cathode. Low activation energies are also obtained with the developed cathodes, indicating a promising applicability of such nanostructured and Pd-promoted electrodes as cathodes for the intermediate-temperature SOFCs.For solid oxide fuel cells ͑SOFCs͒ based on Y 2 O 3 -doped ZrO 2 ͑YSZ͒ electrolyte, Sr-doped LaMnO 3 ͑LSM͒ perovskite is a widely investigated cathode material because of its thermal and chemical compatibility with YSZ, high electrochemical activity for the O 2 reduction reaction, and high structural stability at high temperatures. 1-4 Numerous attempts have been undertaken to improve the performance of LSM-based cathodes by forming composite. [5][6][7][8][9][10][11][12][13] The conventional approach is to mix an ionic conducting phase, such as YSZ and Gd-doped CeO 2 ͑GDC͒, with electronic conducting LSM to extend the three-phase boundary ͑TPB͒ for the O 2 reduction reaction. Murray et al. 6,10 achieved a reduction in electrode polarization resistance to 15% of the pure LSM electrodes at 700°C by using LSM/YSZ and LSM/GDC composite electrodes. Another strategy is to develop nanostructured composite cathodes by wet impregnation. We have shown that impregnation of ionic conducting GDC particles into porous LSM cathode resulted in a substantial reduction in electrode polarization resistance, as compared to the conventional LSM/YSZ and LSM/GDC composite cathodes. 14,15 Huang et al. have also confirmed the enhancement with LSM-impregnated YSZ composite cathodes prepared at temperatures between 850 and 1250°C. 16 Addition of catalytically active nanoparticles onto the internal surfaces of porous electrodes can increase their performance by facilitating the electrochemical reaction processes on electrodes. [17][18][19][20] Recently we demonstrated substantially low electrode polarization resistance and reduced activation energy for the O 2 reduction reaction on Pd-impregnated YSZ composite cathodes in comparison with conventional LSM/YSZ, LSM/GDC, and mixed ionic and electronic conducting ͑MIEC͒ cathodes such as ͑La,Sr͒͑Co,Fe͒O 3 . 21 LSM has been known to be the most stable cathode material for high-temperature SOFCs; however, it becomes much less performed when the operation temperature is decreased to the intermediate range of 600-800°C due to the negligible ionic conductivity of LSM perovskites. 22 The purpose of this study is to engineer the microstructure and electrocatalytic properties of LSM-based cathodes for applications in intermediate-temperature SOFCs ͑IT-SOFCs͒, using nanostructur...

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“…The polarization potential, E cathode , increases with the cathodic polarization time, showing the typical characteristics of polarization behavior for the reaction in the presence of Fe-Cr alloy. 25,26 However, the magnitude in the increase of R E , E cathode , and for the reaction in the presence of the Fe-Cr metallic interconnect is related to the cathodic polarization time and to the composition of LSBCF. In the initial stages of polarization, the change in R E and is more or less the same for the reaction on the LSBCF cathodes.…”

Section: Resultsmentioning

confidence: 99%

Chromium Deposition and Poisoning on (La[sub 0.6]Sr[sub 0.4−x]Ba[sub x])(Co[sub 0.2]Fe[sub 0.8])O[sub 3] (0≤x≤0.4) Cathodes of Solid Oxide Fuel Cells

Chen

Zhang

Jiang

2008

J. Electrochem. Soc.

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The chromium deposition process at ͑La 0.6 Sr 0.4−x Ba x ͒͑Co 0.2 Fe 0.8 ͒O 3 ͑LSBCF͒ ͑0 ഛ x ഛ 0.4͒ cathodes of solid oxide fuel cells ͑SOFCs͒ has been investigated in the presence of an Fe-Cr metallic interconnect at 900°C. Chromium deposition depends strongly on the composition of LSBCF cathodes as x varies from 0 to 0.4. At x = 0, the Cr deposition is most significant, completely covering the surface of the electrode after polarization at 200 mA cm −2 for 1200 min. As Sr content in LSBCF decreases ͑i.e., Ba content increases͒, the Cr deposition is reduced significantly. The LSBCF electrodes show similar electrocatalytic activities toward the O 2 reduction reaction in the absence of Fe-Cr interconnect and at early stages in the presence of Fe-Cr interconnect. The results clearly show that the significant differences in the Cr deposition are closely related to the Sr and Ba content and are not related to the electrochemical activities of the LSBCF cathodes, indicating that Cr deposition on the LSBCF cathode is not controlled by an electrochemical reduction process of gaseous chromium species.Solid oxide fuel cells ͑SOFCs͒ are widely regarded as promising candidates for future energy conversion technologies due to their high energy conversion efficiency and low greenhouse emission. 1-3 However, development of SOFC technologies still faces many challenges. One of them is the chromium deposition and poisoning of SOFC cathodes by the vaporization of chromium species from the chromia-forming metallic interconnect material. 4 Without effective protective coatings, cathode performance deteriorates very rapidly in contact with chromia-forming metallic interconnect under SOFC operating conditions due to the deposition of chromium oxides at the electrode and electrolyte system. [5][6][7][8][9] The interaction between metallic interconnect and cathodes of SOFCs has been extensively investigated and a great deal of information is available. However, there are still considerable disagreements and debates on the exact mechanism of the chromium poisoning and chromium deposition for the O 2 reduction reaction in the literature, as reviewed recently by Fergus. 10 Taniguchi et al. 11 and Badwal et al. 8 made extensive investigations on chromium poisoning of ͑La,Sr͒MnO 3 ͑LSM͒ cathode in contact with an Fe-Cr metallic interconnect and found that the degradation of the electrochemical activity of the LSM cathode is strongly related to the chromium deposited at the LSM electrode and yttria-stabilized zirconia ͑YSZ͒ electrolyte interface. A mechanism is proposed that the chromium deposition is closely related to the oxygen ͑i.e., electrochemical͒ activities at the electrode/electrolyte interface and is mainly caused by the electrochemical reduction of gaseous, highly valent chromium oxide and oxyhydroxide species to solid Cr 2 O 3 phase in competition with the O 2 reduction reaction at the triple phase boundaries. 6,8,[11][12][13][14] The driving force for chromium deposition, i.e., electrochemical reduction of high valent gaseous Cr...

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Oxygen reduction on strontium-doped LaMnO3 cathodes in the absence and presence of an iron–chromium alloy interconnect

Cited by 38 publications

References 56 publications

Mn‐Stabilised Microstructure and Performance of Pd‐impregnated YSZ Cathode for Intermediate Temperature Solid Oxide Fuel Cells

Mn‐Stabilised Microstructure and Performance of Pd‐impregnated YSZ Cathode for Intermediate Temperature Solid Oxide Fuel Cells

Development of Nanostructured and Palladium Promoted (La,Sr)MnO[sub 3]-Based Cathodes for Intermediate-Temperature SOFCs

Chromium Deposition and Poisoning on (La[sub 0.6]Sr[sub 0.4−x]Ba[sub x])(Co[sub 0.2]Fe[sub 0.8])O[sub 3] (0≤x≤0.4) Cathodes of Solid Oxide Fuel Cells

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