Measurements of Lateral Impedance and Local Characteristics of Solid Oxide Fuel Cells

2012 ◽  
Vol 9 (4) ◽  
Author(s):  
Shih-Wei Cheng ◽  
Yaw-Hwa Shui ◽  
Yung-Neng Cheng ◽  
Ruey-Yi Lee
Keyword(s):  
Fuel Cells ◽  
Solid Oxide Fuel Cells ◽  
Electrochemical Impedance ◽  
Open Circuit ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Local Characteristics ◽  
Eis Measurements ◽  
Original Cell ◽  
Lower Impedance

Lateral impedance and local characteristics of anode-supported solid oxide fuel cells (SOFCs) are studied in this paper. The testing device, which combines the original cell housing with a four-point probe equipment, is set for measuring SOFC single cell. The current collectors on anode and cathode in the original cell housing are, respectively, replaced by four independent probe units. They are not only to collect current, but also become measuring probes. Therefore, the lateral impedance of anode and cathode can be measured. Furthermore, the local characteristics are examined by open circuit voltage (OCV), I-V curve, and electrochemical impedance spectroscopy (EIS) measurements. The results show that the lateral impedance is substantially varied with temperature, the OCV at the center of the cell are higher than the edge, the central location on cell have better performance and lower impedance than the marginal location.

scholarly journals Fabrication and Electrochemical Performance of Zn-Doped La0.2Sr0.25Ca0.45TiO3 Infiltrated with Nickel-CGO, Iron, and Cobalt as an Alternative Anode Material for Solid Oxide Fuel Cells

Catalysts ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 269 ◽  
Author(s):  
Nazan Muzaffar ◽  
Nasima Arshad ◽  
Daniel Drasbæk ◽  
Bhaskar Sudireddy ◽  
Peter Holtappels
Keyword(s):  
Fuel Cells ◽  
Electrochemical Performance ◽  
Solid Oxide Fuel Cells ◽  
Polarization Resistance ◽  
Electrochemical Impedance ◽  
Open Circuit ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Sulphur Poisoning ◽  
Operating Temperatures

In solid oxide fuel cells, doped strontium titinates have been widely studied as anode materials due to their high n-type conductivity. They are used as current conducting backbones as an alternative to nickel-cermets, which suffer degradation due to coking, sulphur poisoning, and low tolerance to redox cycling. In this work, anode backbone materials were synthesized from La0.2Sr0.25Ca0.45TiO3−δ (LSCTA-), modified with 5 wt.% Zn, and infiltrated with nickel (Ni)/ceria gadolinium-doped cerium oxide (CGO), Fe, and Co. The electrodes were further studied for their electrochemical performance using electrochemical impedance spectroscopy (EIS) at open circuit voltage (OCV) in different hydrogen to steam ratios and at various operating temperatures (850–650 °C). Infiltration of electrocatalysts significantly reduced the polarization resistance and among the studied infiltrates, at all operating temperatures, Ni-CGO showed excellent electrode performance. The polarization resistances in 3% and 50% H2O/H2 atmosphere were found to be 0.072 and 0.025 Ω cm2, respectively, at 850 °C, and 0.091 and 0.076 Ω cm2, respectively, at 750 °C, with Ni-CGO. These values are approximately three orders of magnitude smaller than the polarization resistance (25 Ω cm2) of back bone material measured at 750 °C.

scholarly journals Remarkable Ionic Conductivity in a LZO-SDC Composite for Low-Temperature Solid Oxide Fuel Cells

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2277
Author(s):  
Zhengwen Tu ◽  
Yuanyuan Tian ◽  
Mingyang Liu ◽  
Bin Jin ◽  
Muhammad Akbar ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Ionic Conductivity ◽  
Low Temperature ◽  
Solid Oxide Fuel Cells ◽  
Ionic Conduction ◽  
Open Circuit ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Open Circuit Voltages ◽  
Composite Samples

Recently, appreciable ionic conduction has been frequently observed in multifunctional semiconductors, pointing out an unconventional way to develop electrolytes for solid oxide fuel cells (SOFCs). Among them, ZnO and Li-doped ZnO (LZO) have shown great potential. In this study, to further improve the electrolyte capability of LZO, a typical ionic conductor Sm0.2Ce0.8O1.9 (SDC) is introduced to form semiconductor-ionic composites with LZO. The designed LZO-SDC composites with various mass ratios are successfully demonstrated in SOFCs at low operating temperatures, exhibiting a peak power density of 713 mW cm−2 and high open circuit voltages (OCVs) of 1.04 V at 550 °C by the best-performing sample 5LZO-5SDC, which is superior to that of simplex LZO electrolyte SOFC. Our electrochemical and electrical analysis reveals that the composite samples have attained enhanced ionic conduction as compared to pure LZO and SDC, reaching a remarkable ionic conductivity of 0.16 S cm−1 at 550 °C, and shows hybrid H+/O2− conducting capability with predominant H+ conduction. Further investigation in terms of interface inspection manifests that oxygen vacancies are enriched at the hetero-interface between LZO and SDC, which gives rise to the high ionic conductivity of 5LZO-5SDC. Our study thus suggests the tremendous potentials of semiconductor ionic materials and indicates an effective way to develop fast ionic transport in electrolytes for low-temperature SOFCs.

Microstructure, Sinterability and Electrochemical Properties of a Sm-Sr-(Co,Fe,Ni)-O Cathode System for Solid Oxide Fuel Cells

2009 ◽  
Author(s):  
Seung-Wook Baek ◽  
Joongmyeon Bae
Keyword(s):  
Fuel Cells ◽  
Solid Oxide Fuel Cells ◽  
Electrochemical Properties ◽  
Electrochemical Impedance ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Sofc Cathode ◽  
Low Thermal Expansion ◽  
Temperature Operating ◽  
The Relationship

Samarium (Sm) is a rare earth material that shows promise for use in cathodes of intermediate temperature-operating solid oxide fuel cells (IT-SOFCs). Perovskite-structured oxide containing Sm has very attractive electrocatalytic properties, and spinel-structured oxide generally exhibits low thermal expansion, indicating its suitability for application as a SOFC cathode. In this paper, the characteristics of the various Sm-based oxide materials (Sm-Sr-(Co,Fe,Ni)-O) deposited on Sm0.2Ce0.8O1.9 (SDC) electrolyte pellets were investigated in terms of their microstructure, sinterability and electrochemical properties. The relationship between the composition and the sintering temperature was studied and discussed. Results show that the substitution of iron (Fe) and nickel (Ni) in Co-sites affects the sinterability, adhesion to the electrolyte and electrochemical activity, such that the different sintering temperatures for these compositions should be considered. The microstructure and sinterability of the cathodes were investigated using a scanning electron microscope (SEM). Area specific resistance (ASR) values for all cathode compositions were measured using AC electrochemical impedance spectroscopy (EIS).

Characterization of SOFCS: A Crystallographic Analysis and First Steps towards an Impedance Spectroscopy Approach

2012 ◽  
Vol 727-728 ◽  
pp. 769-774
Author(s):  
A. Ávila ◽  
J. Poveda ◽  
D. Gómez ◽  
D. Hotza ◽  
J. Escobar
Keyword(s):  
Fuel Cells ◽  
Impedance Spectroscopy ◽  
Solid Oxide Fuel Cells ◽  
Electrochemical Impedance ◽  
Electrical Energy ◽  
Crystallographic Analysis ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Major Disadvantage ◽  
Different Temperatures

Solid oxide fuel cells (SOFCs) have emerged as an efficient way to transform chemical energy into electrical energy. However, a major disadvantage of this technology is related to the high temperatures required for SOFC operation. In this way, new materials are necessary to maintain the electrical properties of the cell at intermediate temperatures. Based on these ideas, it is necessary to study both the structural variation of the cells components at different temperatures and their electrochemical behavior. In this work, a crystallographic characterization is presented, which was performed in a commercial SOFC cell using X-ray diffraction (XRD). An equivalent linear electrical model to predict SOFC losses is developed as well. Keywords: Solid oxide fuel cells (SOFCs); AC impedance; Electrochemical impedance spectroscopy (EIS); Equivalent circuit models.

scholarly journals Characterization of Glass-Ceramic Sealant for Solid Oxide Fuel Cells at Operating Conditions by Electrochemical Impedance Spectroscopy

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4702
Author(s):  
Roberto Spotorno ◽  
Marlena Ostrowska ◽  
Simona Delsante ◽  
Ulf Dahlmann ◽  
Paolo Piccardo
Keyword(s):  
Fuel Cells ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Solid Oxide Fuel Cells ◽  
Glass Ceramic ◽  
Electrochemical Impedance ◽  
Electrical Response ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
X Ray

A commercially available glass-ceramic composition is applied on a ferritic stainless steel (FSS) substrate reproducing a type of interface present in solid oxide fuel cells (SOFCs) stacks. Electrochemical impedance spectroscopy (EIS) is used to study the electrical response of the assembly in the temperature range of 380–780 °C and during aging for 250 h at 780 °C. Post-experiment analyses, performed by means of X-ray diffraction (XRD), and along cross-sections by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis, highlight the microstructural changes promoted by aging conditions over time. In particular, progressive crystallization of the glass-ceramic, high temperature corrosion of the substrate and diffusion of Fe and Cr ions from the FSS substrate into the sealant influence the electrical response of the system under investigation. The electrical measurements show an increase in conductivity to 5 × 10−6 S∙cm−1, more than one order of magnitude below the maximum recommended value.

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