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.

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 Structural and Electrochemical Properties of Lanthanum Silicate Apatites La10Si6−x−0.2AlxZn0.2O27−δ for Solid Oxide Fuel Cells (SOFCs)

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Shammya Afroze ◽  
Hidayatul Qayyimah Hj Hairul Absah ◽  
Md Sumon Reza ◽  
Mahendra Rao Somalu ◽  
Jun-Young Park ◽  
...  
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Solid Oxide ◽  
Ion Conductivity ◽  
Oxide Fuel ◽  
X Ray ◽  
Oxide Ion Conductivity ◽  
Lanthanum Silicate ◽  
Oxide Ion

An excellent oxide ion conductivity with high oxygen transportation of lanthanum silicate apatite at the solid oxide fuel cell (SOFC) can be achieved through the solid-state reaction method. The doped La10Si6−x−0.2AlxZn0.2O27−δ (x = 0.2 and 0.4) materials sintered at 1600°C accomplished crystallinity and crystal structure of apatite-type. The structural and electrochemical characterizations of La10Si6−x−0.2AlxZn0.2O27−δ (x = 0.2 and 0.4) were executed using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and electrochemical impedance spectroscopy (EIS) measurements. The total oxide ion conductivities of La10Si6−x−0.2AlxZn0.2O27−δ (x = 0.2 and 0.4) were measured from low to intermediate operating temperature range (450 to 800°C) using electrochemical impedance spectroscopy. Room temperature XRD patterns of La10Si6−x−0.2AlxZn0.2O27−δ (x = 0.2 and 0.4) exhibited La10Si6O27 apatite phase with space group P63/m as the main phase with the minor appearance of La2SiO5 as an impurity phase. The highest total oxide ion conductivity of 3.24 × 10−3 Scm−1 and corresponding activation energy of 0.30 eV at 800°C were obtained for La10Si5.6Al0.2Zn0.2O26.7 which contains a low concentration of Al3+ dopant.

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