Analysis of Impedance Spectra for Segmented-in-Series Tubular Solid Oxide Fuel Cells

Liu, Bin; Muroyama, Hiroki; Matsui, Toshiaki; Tomida, Kazuo; Kabata, Tatsuo; Eguchi, Koichi

doi:10.1149/1.3494214

Cited by 111 publications

(70 citation statements)

References 23 publications

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“…The change in a high frequency (1 kHz) peak is attributed to a slower oxygen ion transport from the electrode to the cathode/electrolyte interface. 6,22 With an increase in Cu content, the area of cathodic peaks increases by 42% (10 mol% Cu), indicating a higher resistance in cathodic processes. This increase is consistent with the higher electrode polarization in Cu doped electrodes, as shown in Figures 10d-10f at 0 th hour.…”

Section: Resultsmentioning

confidence: 99%

Activity and Stability of (Pr_1-xNd_x)₂NiO_4+δas Cathodes for Oxide Fuel Cells: Part VI. The Role of Cu Dopant on the Structure and Electrochemical Properties

Dogdibegovic

Yan

Cai

et al. 2017

J. Electrochem. Soc.

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Phase instability in praseodymium nickelates is a major concern for the long-term operations of solid oxide fuel cells since it may lead to the performance degradation. In this work, praseodymium nickelates (ex. Pr 2 NiO 4+δ ) have been stabilized via substitution on both Pr-and Ni-sites. Systematic studies over a wide range of compositions were conducted via long-term thermal annealing studies (T ≤ 870 • C) and electrochemical tests in full cells. Proposed (Pr 0.50 Nd 0.50 ) 2 Ni 1-y Cu y O 4+δ compositions (y = 0. 05, 0.10, 0.20, and 0.30) showed the most promising results and serve as a comprehensive extension to our previous studies in this series of papers. A stable long-term performance was obtained for temperatures up to 790 • C for 500 hours at 0.80 V with a minimal tradeoff between the activity (power density of 0. Solid oxide fuel cells (SOFCs) attract growing interests as residential and industrial power sources primarily because of their high flexibility to a wide variety of fuels, including CO, hydrocarbons, and coal. In addition, SOFCs exhibit a high efficiency in combined heat and power systems (up to 80%) due to the direct conversion of chemical energy to electricity and heat, which is not limited by the Carnot cycle.1-3 Moreover, SOFC power systems are more affordable alternative to unreliable backup power systems that often tend to fail during startups and are only used in cases of main grid failures. 4 One of the key components in an SOFC is the cathode which catalyzes the oxygen reduction reaction (ORR). Cathodes with a low polarization resistance, stable structure, and stable performance over a wide temperature window are highly desired. A recent interest for Pr 2 NiO 4+δ (PNO) 5 stems from its superior properties over commonly used cathode materials 6 and the ability to accept various substituents at Pr and/or Ni sites, which allows for modifications of material's intrinsic properties.5,7 Such properties allow the PNO to be used on commonly utilized yttrium stabilized zirconia and gadolinium doped ceria electrolytes.PNO-based SOFCs, however, exhibit a performance degradation, 6,8 which may be linked to a rapid phase transition in PNO, 9 thus require means to stabilize its crystal structure. It has been a challenge to develop a compositional window which results in both stable structure and desirable catalytic activity. Our recent report 6 shows that A-site substitution with Nd in (Pr 1-x Nd x ) 2 NiO 4+δ cathodes is a promising solution to stabilize the cell performance. However, with a low Nd-content (≤ 50 mol%), a long-term operation leads to phase transition. In contrast, a high Nd content results in a stable phase during a 2,500-hour test, 10 but with a much lower performance (fourfold decrease). Therefore, further compositional modifications are required to simultaneously obtain high catalytic activity and stable crystal structure.An approach taken in this work was to substitute the Nisite in a promising (Pr 0.50 Nd 0.50 ) 2 NiO 4+δ (PNNO5050) electrode, * Electrochemical Society M...

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Section: Resultsmentioning

confidence: 99%

Activity and Stability of (Pr_1-xNd_x)₂NiO_4+δas Cathodes for Oxide Fuel Cells: Part VI. The Role of Cu Dopant on the Structure and Electrochemical Properties

Dogdibegovic

Yan

Cai

et al. 2017

J. Electrochem. Soc.

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“…47,48 The change in the size of impedance arcs is very small with the cathodic polarization time at 800…”

Section: Resultsmentioning

confidence: 99%

Thermally and Electrochemically Induced Electrode/Electrolyte Interfaces in Solid Oxide Fuel Cells: An AFM and EIS Study

Jiang

2015

J. Electrochem. Soc.

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In high temperature solid oxide fuel cells (SOFCs), electrode/electrolyte interfaces play a critical role in the electrocatalytic activity and durability of the cells. In this study, thermally and electrochemically induced electrode/electrolyte interfaces were investigated on pre-sintered and in situ assembled (La 0.8 Sr 0.2 ) 0.90 MnO 3 (LSM) and La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ (LSCF) electrodes on Y 2 O 3 -ZrO 2 (YSZ) and Gd 0.2 Ce 0.8 O 2 (GDC) electrolytes, using atomic force microscopy (AFM) and electrochemical impedance spectroscopy (EIS). The results indicate that thermally induced interface is characterized by convex contact rings with depth of 100-400 nm and diameter in agreement with the particle size of pre-sintered LSM and LSCF electrodes, while the electrochemically induced interfaces under cathodic polarization conditions on in situ assembled electrodes are characterized by particle-shaped contact marks or clusters (50-100 nm in diameter). The number and distribution of contact clusters depend on the cathodic current density as well as the electrode and electrolyte materials. The contact clusters on the in situ assembled LSCF/GDC interface are substantially smaller than that on the in situ assembled LSM/GDC interface likely due to the high mixed ionic and electronic conductivities of LSCF materials. The results show that the electrochemically induced interface is most likely resulting from the incorporation of oxygen species and cation interdiffusion under cathodic polarization conditions. However, the electrocatalytic activity of electrochemically induced electrode/electrolyte interfaces is comparable to the thermally induced interfaces for the O 2 reduction reaction under SOFC operation conditions. © The Author Solid oxide fuel cell (SOFC) is one of the most efficient technologies for the conversion of chemical energy of fuels such as hydrogen and natural gas directly into electrical power. It employs a solid oxide electrolyte such as yttria-stabilized zirconia (YSZ) that serves as an ionic conductor in the temperature range between 600• C to 1000• C. The electrolyte separates the cathode from the anode and conducts oxygen ions from the cathode to the anode where they react electrochemically with the fuel. Electrons are then released to an external circuit, which provides a useful source of electrical power. The electrochemical reactions such as O 2 reduction at the cathode and H 2 oxidation at the anodes occur at the electrode/electrolyte interface regions.1-3 Thus, in SOFCs, electrode/electrolyte interfaces play a vital role in the mechanism and kinetics of the electrochemical reactions and in the fundamental understanding of the relationship between the electrochemical processes and microstructure.4-10 The cell performance and durability also depend strongly on the microstructural change at the interface under SOFC operation conditions. 11,12Lanthanum strontium manganite (LSM) is one of the most common cathode materials for SOFCs because of high electrical conductivity, good thermal and chem...

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“…The area under each DRT peak reflects the corresponding resistance of individual electrode process. The detailed process of DRT calculation strictly followed the procedures stated in Liu et al [25] using software package Ftikreg. Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Fig. 5 (aec) shows the DRT plots of the three tested cells at different temperatures and the inserts of (a) and (c) present the transformation of DRT plots as a function of P O2 for the LSM- oxygen intermediate species and oxygen reduction process, respectively [25,29,30]. P1A in 8000~2000 Hz, P2A in 1500~1000 Hz and P3A with summit frequency at 5 Hz, which do not change with cathode composition and P O2 , are three anodic processes.…”

Section: Resultsmentioning

confidence: 99%

High performance solid oxide fuel cells with Co1.5Mn1.5O4 infiltrated (La,Sr)MnO3-yittria stabilized zirconia cathodes

Zhang

Liu

Zhao

et al. 2015

International Journal of Hydrogen Energy

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Analysis of Impedance Spectra for Segmented-in-Series Tubular Solid Oxide Fuel Cells

Cited by 111 publications

References 23 publications

Activity and Stability of (Pr_1-xNd_x)₂NiO_4+δas Cathodes for Oxide Fuel Cells: Part VI. The Role of Cu Dopant on the Structure and Electrochemical Properties

Activity and Stability of (Pr_1-xNd_x)₂NiO_4+δas Cathodes for Oxide Fuel Cells: Part VI. The Role of Cu Dopant on the Structure and Electrochemical Properties

Thermally and Electrochemically Induced Electrode/Electrolyte Interfaces in Solid Oxide Fuel Cells: An AFM and EIS Study

High performance solid oxide fuel cells with Co1.5Mn1.5O4 infiltrated (La,Sr)MnO3-yittria stabilized zirconia cathodes

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Analysis of Impedance Spectra for Segmented-in-Series Tubular Solid Oxide Fuel Cells

Cited by 111 publications

References 23 publications

Activity and Stability of (Pr1-xNdx)2NiO4+δas Cathodes for Oxide Fuel Cells: Part VI. The Role of Cu Dopant on the Structure and Electrochemical Properties

Activity and Stability of (Pr1-xNdx)2NiO4+δas Cathodes for Oxide Fuel Cells: Part VI. The Role of Cu Dopant on the Structure and Electrochemical Properties

Thermally and Electrochemically Induced Electrode/Electrolyte Interfaces in Solid Oxide Fuel Cells: An AFM and EIS Study

High performance solid oxide fuel cells with Co1.5Mn1.5O4 infiltrated (La,Sr)MnO3-yittria stabilized zirconia cathodes

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Activity and Stability of (Pr_1-xNd_x)₂NiO_4+δas Cathodes for Oxide Fuel Cells: Part VI. The Role of Cu Dopant on the Structure and Electrochemical Properties

Activity and Stability of (Pr_1-xNd_x)₂NiO_4+δas Cathodes for Oxide Fuel Cells: Part VI. The Role of Cu Dopant on the Structure and Electrochemical Properties