Improved Tolerance of Lanthanum Nickelate (La2NiO4+δ) Cathodes to Chromium Poisoning Under Current Load in Solid Oxide Fuel Cells

Gong, Yiwen; Wang, Ruofan; Banner, Jane; Basu, Soumendra N.; Pal, Uday B.; Gopalan, Srikanth

doi:10.1007/s11837-019-03724-0

Cited by 10 publications

(6 citation statements)

References 39 publications

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“…Meanwhile, Cr-tolerant cathodes are being actively investigated since no matter how much effort is made, volatile Cr species still cannot be removed from the heated cathode air. Among them, Ruddlesden–Popper-phase LaNiO 4+δ (LNO) shows strong Cr tolerance and relatively good electrochemical performance for cathode reaction. − This Sr-free composition gives LNO strong tolerance to Cr deposition that proceeds through SrO-CrO 3 reaction. However, the performance of LNO is still not a match to LSCF in general.…”

Section: Introductionmentioning

confidence: 99%

High-Entropy Perovskite as a High-Performing Chromium-Tolerant Cathode for Solid Oxide Fuel Cells

Guan

Xia

et al. 2022

ACS Appl. Mater. Interfaces

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To achieve chromium tolerance and high performance, a new series of high-entropy perovskites (HEPs) are investigated as cathode materials for solid oxide fuel cells (SOFCs). Multiple rareearth, alkaline-earth, and high-order transition metal elements are used for the A-site of this ABO 3 structure. A pure phase is achieved through the designed combination of different elements in seven out of eight candidates. Due to the retaining of alkaline-earth elements Sr and/or Ba, the electrical conductivities of these HEPs are in the order of 100 S/cm at 550−700 °C, a value that can practically eliminate the electronic resistance of the porous cathode. Three out of eight candidates show similar or better performance than the (La 0.6 Sr 0.4 )(Co 0.2 Fe 0.8 )O 3−δ (LSCF) benchmark. It is found that A-site elements can cast a substantial influence on the overall performance even with a change as small as 10% of the total cations. It seems that each element has its individual "phenomenal activity" that can be transferred from one candidate to the other in the general setting of the perovskite structure, leading to the best candidate by using the three most active elements simultaneously at the A-site. Excellent Cr tolerance has been observed on the (La 0.2 Sr 0.2 Pr 0.2 Y 0.2 Ba 0.2 )Co 0.2 Fe 0.8 O 3−δ sample, showing degradation of only 0.25%/kh during a 41 day operation in the presence of Cr, while LSCF increases by 100% within the first day in the same condition. X-ray photoelectron spectroscopy discovers no Sr segregation as LSCF is found in this HEP; rather, the active element Y takes more A-sites on the outermost layer after long-term operation.

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Section: Introductionmentioning

confidence: 99%

High-Entropy Perovskite as a High-Performing Chromium-Tolerant Cathode for Solid Oxide Fuel Cells

Guan

Xia

et al. 2022

ACS Appl. Mater. Interfaces

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“…It is believed that chromium deposition in LNO electrodes can occur by both chemical and electrochemical mechanisms, such as for the aforementioned LSM and LSCF electrodes. TEM‐EDX measurements have shown that during chemical deposition, chromium dissolves into the LaNiO 3 blocks of the La 2 NiO 4+ δ to form LaNi 0.7 Cr 0.3 O 3 57,58 . In Reference 58, it was determined that the Cr‐enrichment ratios increase with the distance from the triple‐phase boundaries, as opposed to LSM electrodes characterized by the predominant chromium deposition at the electrode ‐ electrolyte interface.…”

Section: Introductionmentioning

confidence: 99%

“…At the same time, the chromium poisoning of LNO electrodes via the electrochemical mechanism is accelerated by the current density and humidity, as in the case of other electrode materials. In Reference 58, it was demonstrated that the amount of chromium that is evaporated from Crofer 22 H and deposited in the LNO electrode depends on the test conditions and increases: dry air + open circuit ~ dry air + 0.05 A cm −2 < dry air + 0.2 A cm −2 < 10% humidified air + 0.05 A cm −2 .…”

Section: Introductionmentioning

confidence: 99%

“…TEM‐EDX measurements have shown that during chemical deposition, chromium dissolves into the LaNiO 3 blocks of the La 2 NiO 4+ δ to form LaNi 0.7 Cr 0.3 O 3 57,58 . In Reference 58, it was determined that the Cr‐enrichment ratios increase with the distance from the triple‐phase boundaries, as opposed to LSM electrodes characterized by the predominant chromium deposition at the electrode ‐ electrolyte interface. At the same time, the chromium poisoning of LNO electrodes via the electrochemical mechanism is accelerated by the current density and humidity, as in the case of other electrode materials.…”

Section: Introductionmentioning

confidence: 99%

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Revealing the degradation mechanism of the lanthanum nickelates based double‐layer electrodes during long‐term tests in contact with chromium‐containing steel interconnects

Solodyankin

Еремин

Ananyev

et al. 2022

Intl J of Energy Research

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Summary This paper focuses on the long‐term tests for 1000 hours of different Membrane‐Electrode‐Interconnect Assemblies (MEIAs), consisting of a steel interconnect and an asymmetrical solid electrochemical cell based on the Ce0.8Sm0.2O2−δ electrolyte, the double‐layer working electrode with the La2NiO4+δ – Ce0.8Sm0.2O2−δ composite functional layer and the LaNi0.6Fe0.4O3−δ current collector layer, and the platinum reference electrode (O2, LaNi0.6Fe0.4O3−δ|La2NiO4+δ – Ce0.8Sm0.2O2−δ|Ce0.8Sm0.2O2−δ|Pt, O2). These tests were carried out on MEIAs with two types of Cr‐based stainless steels, Crofer 22 APU and 08X17T, with and without protective coatings at 850°C in air. The electrochemical performance of MEIAs was studied without polarization as well as under cathodic and anodic polarization (current density was 0.5 A cm−2) by means of electrochemical impedance spectroscopy (EIS) and the distribution of relaxation times method (DRT). It was found that the proposed protective coatings for the stainless steels inhibit chromium poisoning without polarization and under anodic polarization: for Crofer 22 APU the degradation of the polarization resistance after ~1100 hours of exposure was 0.35 ± 0.05 Ω cm2, and for 08X17T it was from 0.40 ± 0.05 Ω cm2. In the case of cathodic polarization, the degradation of the polarization resistance remained at a very high level, comparable to uncoated samples: for Crofer 22 APU and 08X17T with coatings, it was about 0.6 to 0.8 Ω cm2 after ~1100 hours. Post‐test analysis of the microstructure and chemical composition of the interconnect ‐ double‐layer electrode interface was carried out using scanning electron microscopy (SEM), wavelength dispersive X‐ray spectrometry (WDS), and respective image analysis of the obtained data. The influence of chromium poisoning on the degradation was considered for different stages of the electrode performance. It was demonstrated that chromium predominantly accumulates in the current collector layer in the case of anodic polarization and in the functional layer in the cases of open circuit and cathodic polarization. For the first time, a combined electrochemical‐chemical degradation mechanism of the La2NiO4+δ – Ce0.8Sm0.2O2−δ functional layer was discussed. Highlights Long‐term tests of Membrane‐Electrode‐Inteconnect Assembles (MEIAs) were done. Chromium poisoning was detected on MEIAs with the interconnects without coating. Cathodic polarization terminates the protective properties of the coatings. Chromium poisoning decreases electrode activity to oxygen exchange and diffusivity. A combined electrochemical‐chemical degradation mechanism of the functional layer was revealed.

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“…[7][8][9] Therefore, the Sr-free K 2 NiF 4 -type rare-earth nickelates have been considered to be potentially more resilient to Cr-poisoning. So far, several Cr-poisoning studies on rare-earth nickelates have been published for La 2 NiO 4+δ [10][11][12][13][14][15][16][17][18] and Nd 2 NiO 4+δ . [19][20][21][22][23] However, no such studies are available for Pr 2 NiO 4+δ , which is quite surprising, considering that Pr-nickelates show very high performance as SOEC/SOFC air electrodes matching current state-of-the-art materials like LSCF.…”

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confidence: 99%

Long-Term Stability of Pr₂NiO_4+δ Air Electrodes for Solid Oxide Cells against Chromium Poisoning

Schrödl

Egger

Lammer

et al. 2021

J. Electrochem. Soc.

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Long-term stability tests are performed at 800 °C on Pr2NiO4+δ air electrodes by use of a symmetrical button cell with Ce0.9Gd0.1O1.95 as solid electrolyte. The experiments are carried out by means of electrochemical impedance spectroscopy and current-voltage measurements with and without current load under dry and humid conditions in the presence of a chromium source. Chromium poisoning of Pr2NiO4+δ air electrodes is investigated for periods of several hundred hours at 30% relative humidity. In order to separate the influence of anodic and cathodic electrode polarization on Cr-deposition, measurements are conducted using a Pt-reference electrode. The electrode performance is found to remain fairly stable under dry conditions, even when a current is drawn. However, after volatile Cr-species in a humid atmosphere are introduced, the cell performance starts to deteriorate and the polarization resistance contribution of the SOFC cathode increases significantly. After several thousand hours, the electrodes are analyzed by means of analytical electron microscopy. Detailed post-test analyses provide evidence for a correlation between the extent of Cr-deposition and electrode degradation in SOFC as well as SOEC mode. Based on these findings, enhanced resilience of Pr2NiO4+δ against Cr-poisoning in SOEC mode can be established.

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Improved Tolerance of Lanthanum Nickelate (La2NiO4+δ) Cathodes to Chromium Poisoning Under Current Load in Solid Oxide Fuel Cells

Cited by 10 publications

References 39 publications

High-Entropy Perovskite as a High-Performing Chromium-Tolerant Cathode for Solid Oxide Fuel Cells

High-Entropy Perovskite as a High-Performing Chromium-Tolerant Cathode for Solid Oxide Fuel Cells

Revealing the degradation mechanism of the lanthanum nickelates based double‐layer electrodes during long‐term tests in contact with chromium‐containing steel interconnects

Long-Term Stability of Pr₂NiO_4+δ Air Electrodes for Solid Oxide Cells against Chromium Poisoning

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Improved Tolerance of Lanthanum Nickelate (La2NiO4+δ) Cathodes to Chromium Poisoning Under Current Load in Solid Oxide Fuel Cells

Cited by 10 publications

References 39 publications

High-Entropy Perovskite as a High-Performing Chromium-Tolerant Cathode for Solid Oxide Fuel Cells

High-Entropy Perovskite as a High-Performing Chromium-Tolerant Cathode for Solid Oxide Fuel Cells

Revealing the degradation mechanism of the lanthanum nickelates based double‐layer electrodes during long‐term tests in contact with chromium‐containing steel interconnects

Long-Term Stability of Pr2NiO4+δ Air Electrodes for Solid Oxide Cells against Chromium Poisoning

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Long-Term Stability of Pr₂NiO_4+δ Air Electrodes for Solid Oxide Cells against Chromium Poisoning