Influence of Water Vapor on Sulfur Distribution Within La0.6Sr0.4Co0.2Fe0.8O3 Cathode

Wang, Fangfang; Yamaji, Katsuhiko; Cho, Do-Hyung; Shimonosono, Taro; Nishi, Mina; Kishimoto, Haruo; Brito, Manuel E.; Horita, Teruhisa; Yokokawa, Harumi

doi:10.1149/05027.0143ecst

Cited by 9 publications

(14 citation statements)

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“…1,2 Many studies have investigated the sulfur poisoning behavior of cathode materials such as La 1−x Sr x CoO 3−δ (LSC), La 1−x Sr x MnO 3−δ (LSM), La 1−x Sr x Co 0.2 Fe 0.8 O 3−δ (LSCF) and tried to clarify their degradation mechanisms. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] For LSM, essentially no cathode performance degradation occurs. Secondary phase formation, if any, can take place at any area of the cathode showing no selectivity near the triple-phase boundary (TPB) at the electrode/electrolyte interfaces.…”

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confidence: 99%

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Effect of Operating Temperature on Sulfur Distribution and Performance Degradation of Porous La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ Electrode

Wang

Yan

Budiman

et al. 2020

J. Electrochem. Soc.

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The effect of low concentrations of SO 2 (0.01 ppm) in air on the degradation of a porous La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 (LSCF) electrode was investigated as a function of operating temperature. At 1073 K, most of the introduced SO 2 became trapped as SrSO 4 in the vicinity of the air inlet, and consequently the degradation of cathode performance was not observed. At 973 K and 923 K, the SO 2 reached directly the electrochemically active region. Thus, the formed SrSO 4 caused a gradual decrease in cathode performance. These results suggest that sulfur poisoning behavior at 0.01 ppm SO 2 is mainly governed by two processes, the chemical reactions in the vicinity of air inlet and the electrochemically enhanced reactions in the active region; the former is strongly enhanced by temperature, whereas the latter additionally by the applied overpotential. SEM-EDX analysis confirmed the sulfur distribution was correlated to the degradation in the electrode performance. The concentration of SrSO 4 found near the triple-phase boundaries corresponded to the case where both the polarization and the ohmic resistances increased. Typical values for the effective reaction length essentially correlated with the k* and D* values obtained using the transmission line model. Results are in order-ofmagnitude agreement with the features obtained using SEM-EDX.

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confidence: 99%

“…The sulfur poisoning effects on the LSCF cathode has been investigated in high concentrations of SO 2 (0.1, 1, 10, 100 ppm SO 2 in air). [6][7][8][9][10] It was found that SO 2 reacts with the Sr component in LSCF to form SrSO 4 , which leads to the performance degradation. With increasing sulfur concentration, faster degradation was observed.…”

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confidence: 99%

Effect of Operating Temperature on Sulfur Distribution and Performance Degradation of Porous La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ Electrode

Wang

Yan

Budiman

et al. 2020

J. Electrochem. Soc.

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“…Researchers have also found that levels of sulfur at the ppb level in the form of SO 2 can cause serious performance degradation in cathodes 33 . This seems to be related to the surface strontium enrichment described above, with surface strontium forming SrSO 4 , likely triggering the local decomposition of the cathode material or reducing the strontium content in the bulk enough to reduce the conductivity 34 . Sulfur tolerant cathode materials need to be developed, as the current solution is a chemical sulfur scrubber, which inevitably increases cost and decreases efficiency and power density.…”

Section: Lifetime and Degradationmentioning

confidence: 98%

Progress and outlook for solid oxide fuel cells for transportation applications

2019

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With their high temperatures and brittle ceramic components, solid oxide fuel cells (SOFCs) might not seem the obvious fit for a power source for transportation applications. However, over recent years advances in materials and cell design have begun to mitigate these issues, leading to the advantages of SOFCs such as fuel flexibility and high efficiency being exploited in vehicles. Here we review the advances in SOFC technology which have led to this, look at the vehicles that SOFCs have already been used in, and discuss the areas which need improvement for full commercial breakthrough, and the ways in which catalysis science can assist with these. In particular we identify lifetime and degradation, fuel flexibility, efficiency and power density for improvement, and areas of catalysis science ranging from surface science and computational materials design to improvements in reforming catalysts and reformer design as key to this. MainDecarbonising transport is one of the largest challenges in the global response to climate change. Globally, transport is responsible for 23% of emissions and currently relies on hydrocarbons for 92% of its energy 1 . Decarbonisation is particularly difficult for transportation, because one of the key requirements for the energy source is portability, and hydrocarbons are one of the most energy dense substances available. In addition, the public health burden from pollutants such as particulates, nitrogen oxides and sulfur oxides emitted by vehicles is large, so cleaner energy sources are required.Efforts in transportation have focussed on batteries and polymer electrolyte fuel cells (PEFCs) running on hydrogen, alongside efficiency improvements and fuel switching. Although over the last decade batteries have been the dominant technology because they have advantages over fuel cells in manufacturing, cost, responsiveness in a vehicle and availability of supporting infrastructure, in the longer-term fuel cells may have advantages in some areas. The clearest advantage of fuel cells is high energy density, where it's not known whether battery technology will ever advance far enough to power long-distance transportation such as ships or intercontinental flights. In the area of passenger vehicles, with high battery vehicle penetration, much of the local grid infrastructure such as substations may not be able to cope and may have to be replaced -it is not clear at the moment whether this will be more expensive and disruptive than the rollout of the hydrogen-fuelling network which would be needed to support fuel cell vehicles. In applications such as buses where fast charging/refuelling is needed, fuel cells also possess an innate advantage. Finally, the wider advantage of switching to a hydrogen-fuelled transportation system is that electrolysers can be used to smooth the intermittent supply from renewable energy, while at the same time producing hydrogen fuel for vehicles.One technology which was until relatively recently deemed unsuitable for transportation, but nevertheless has unique ad...

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“…Our group has investigated the degradation behavior of LSCF cathodes induced by SO 2 containing air. It is observed that SO 2 induced degradation is affected by the SO 2 concentration in air [4], the Sr content in LSCF cathode [5], the flow rate of air [6], and the humidity of air [7]. In the present study, we mainly focused on the temperature dependence of degradation behavior of (La 0.6 Sr 0.4 )(Co 0.2 Fe 0.8 )O 3 (LSCF6428) by SO 2 .…”

Section: Introductionmentioning

confidence: 98%

“…Degradation of LSCF cathodes is induced by impurities in air. One of the most recognized impurities is sulfur dioxide (SO 2 ) [1][2][3][4][5][6][7][8][9][10]. Our group has investigated the degradation behavior of LSCF cathodes induced by SO 2 containing air.…”

Section: Introductionmentioning

confidence: 99%

Degradation of LSCF Cathode Induced by SO₂ in Air

et al. 2015

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Sulfur dioxide (SO 2 ) is one of the major impurities in air and it induces performance degradation of SOFC cathodes. Our group has investigated the degradation behavior of (LaSr)(CoFe)O 3 (LSCF) cathodes by sulfur dioxide (SO 2 ) containing air. It is clearly observed that SO 2 -induced degradation is affected by cell operation conditions, such as impurity concentration and the operating temperature. We observed two degradation steps; one is a rapid degradation rate occurring at an early stage and the other is a constant degradation with relatively slow rate. During progress of degradation, both ohmic resistance, R ohm , and oxygen reduction reaction resistance (polarization resistance), R p , increased. There is a relationship between increasing rates of R p and R ohm in each degradation step.

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Influence of Water Vapor on Sulfur Distribution Within La_0.6Sr_0.4Co_0.2Fe_0.8O₃ Cathode

Cited by 9 publications

References 10 publications

Effect of Operating Temperature on Sulfur Distribution and Performance Degradation of Porous La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ Electrode

Effect of Operating Temperature on Sulfur Distribution and Performance Degradation of Porous La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ Electrode

Progress and outlook for solid oxide fuel cells for transportation applications

Degradation of LSCF Cathode Induced by SO₂ in Air

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Influence of Water Vapor on Sulfur Distribution Within La0.6Sr0.4Co0.2Fe0.8O3 Cathode

Cited by 9 publications

References 10 publications

Effect of Operating Temperature on Sulfur Distribution and Performance Degradation of Porous La0.6Sr0.4Co0.2Fe0.8O3−δ Electrode

Effect of Operating Temperature on Sulfur Distribution and Performance Degradation of Porous La0.6Sr0.4Co0.2Fe0.8O3−δ Electrode

Progress and outlook for solid oxide fuel cells for transportation applications

Degradation of LSCF Cathode Induced by SO2 in Air

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Influence of Water Vapor on Sulfur Distribution Within La_0.6Sr_0.4Co_0.2Fe_0.8O₃ Cathode

Effect of Operating Temperature on Sulfur Distribution and Performance Degradation of Porous La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ Electrode

Effect of Operating Temperature on Sulfur Distribution and Performance Degradation of Porous La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ Electrode

Degradation of LSCF Cathode Induced by SO₂ in Air