scholarly journals Synthesis and Characterization of High Temperature Properties of YBa2Cu3O6+δ Superconductor as Potential Cathode for Intermediate Temperature Solid Oxide Fuel Cells

Author(s):  
Joaquín Grassi ◽  
Mario A. Macías ◽  
Juan F. Basbus ◽  
Jorge Castiglioni ◽  
Gilles H. Gauthier ◽  
...  

YBa2Cu3O6+δ (YBC) oxygen deficient perovskite was synthesized by an auto-combustion method and was studied as potential cathode for Intermediate Temperature Solid Oxide Fuel Cell (IT-SOFC). Synchrotron X-ray thermodiffraction in air shows a phase transition from orthorhombic Pmmm to tetragonal P4/mmm space groups at ~ 425 °C. The chemical compatibility with Ce0.9Gd0.1O1.95 (GDC) electrolyte was investigated in air where certain reactivity was observed above 800 °C. However, the main phase is Ba(Ce1-xYx)O3, a good ionic conductor. The catalytic performance in air was obtained by electrochemical impedance spectroscopy (EIS) measurements on YBC/GDC/YBC symmetrical cells. The area specific resistance (ASR) values change from 13.66 to 0.14 Ω cm2 between 500 and 800 °C, with activation energy (Ea) of 0.41 eV. The results suggest potential applications of YBC as IT-SOFC cathode.

Author(s):  
Shih-Wei Cheng ◽  
Yaw-Hwa Shui ◽  
Yung-Neng Cheng ◽  
Ruey-Yi Lee

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.


2019 ◽  
Vol 12 (05) ◽  
pp. 1951001
Author(s):  
Jie Yang ◽  
Changan Tian ◽  
Yu Wang ◽  
Junjie Meng ◽  
Dongdong Ji ◽  
...  

CaxBi[Formula: see text]W[Formula: see text]O[Formula: see text] (CBW) ([Formula: see text], 0.05, 0.10, 0.15, 0.20, 0.30) electrolyte material were synthesized by sol–gel self-combustion method. The samples were characterized by thermogravimetric-differential thermogravimetric analysis(TG-DSC), X-ray diffraction, scanning electron microscopy (SEM), porosity and electrochemical impedance spectroscopy (EIS). The results show the powders CaxBi[Formula: see text]W[Formula: see text]O[Formula: see text] (CBW) with fluorite crystal structure can be obtained after the precursor was calcined at 760∘C. When sintered at 780∘C for 2[Formula: see text]h, the compact ceramic sintered with relative density higher than 97% can be obtained. The electrochemical studies showed that CaxBi[Formula: see text]W[Formula: see text]O[Formula: see text] (CBW) have high ionic conductivity after 780∘C sintering. The sample Ca[Formula: see text]Bi[Formula: see text]W[Formula: see text]O[Formula: see text] exhibits a conductivity of 0.07978 S[Formula: see text][Formula: see text][Formula: see text]cm[Formula: see text] at 750∘C, and the activation energy is 0.845[Formula: see text]eV, which is expected to be applied to the electrolyte materials for intermediate temperature solid oxide fuel cells (SOFC).


Author(s):  
Peter A. Lindahl ◽  
Xuelei Hu ◽  
Joshua Wold ◽  
Matthew Cornachione ◽  
Steven R. Shaw

This paper presents results from an investigation concerning load-induced degradation, recovery, and control of solid oxide fuel cells (SOFCs). In this study, commercially available SOFCs were subject to extended over-current conditions, followed by periods of open-circuit operation. During times of current loading, degradation was observed in the cells’ electrical performance through polarization and electrochemical impedance spectroscopy (EIS) measurements. These measurements showed an increase in the polarization curve’s ohmic region slope, i.e. large-signal resistance, as well as an increase in the cell’s small-signal low-frequency impedance. The degradation was temporary however, as the electrical performance recovered during times of open-circuit operation. These results, attributed to electrochemically-induced oxidation and reduction of nickel in the anode, suggest the degradation phenomenon is controllable via the electrical terminals. As such, an additional test was performed on an SOFC powering a pulse-width modulated load, with the load’s duty-cycle negatively proportional to the cell’s large-signal resistance. Polarization and EIS measurements taken during this test showed that despite the controlled load, degradation occurred throughout the test. However, post-test scanning electron microscope images revealed cracks in the cell’s cathode along the boundary between the active and bulk layers. This type of cracking was not observed in the original degradation and recovery tests, suggesting that the degradation observed in the controlled load test was irreversible and caused by a separate phenomenon.


2011 ◽  
Vol 347-353 ◽  
pp. 3325-3329
Author(s):  
Xin Hui Zhang ◽  
Jie Zhang ◽  
Chao Yuan ◽  
Er Jun Liang

Ceramic systems of template explains and demonstrates how to prepare your camera-ready Ceramic systems of Bi2O3 and La-doped SrTiO3 (LST) solid mixtures La0.2Sr0.8TiO3–x%Bi2O3 (x = 0, 20, 25, 30, 35) are prepared and explored as possible anode materials for solid oxide fuel cells. It is shown that the conductivity of La0.2Sr0.8TiO3–x%Bi2O3 composites increases from 0.15 to 1.4 S cm−1 in 97%H2 +3%H2O at 800°C with increasing the content of Bi2O3. Electrochemical impedance spectra indicated that the addition of Bi2O3 into LST can significantly reduce the fuel cell’s polarization and refine the grains and increase the triple phase boundary, leading to a better performance of the fuel cells. The results suggest potential applications of LST–x%Bi2O3 composite as SOFC anode materials.


2011 ◽  
Vol 192 (1) ◽  
pp. 431-434 ◽  
Author(s):  
Nitish Kumar Singh ◽  
Prabhakar Singh ◽  
Manish Kumar Singh ◽  
Devendra Kumar ◽  
Om Parkash

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