scholarly journals Creating and Preserving Nanoparticles during Co-Sintering of Solid Oxide Electrodes and Its Impact on Electrocatalytic Activity

Catalysts ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1073
Author(s):  
Sixbert P. Muhoza ◽  
Michael D. Gross
Keyword(s):  
Fuel Cell ◽  
Electrocatalytic Activity ◽  
Polarization Resistance ◽  
Electrochemical Impedance ◽  
Cell Polarization ◽  
Solid Oxide ◽  
Electrochemical Impedance Spectra ◽  
Ohmic Resistance ◽  
Oxide Electrodes ◽  
Novel Processing

A novel processing method that creates and preserves ceramic nanoparticles in solid oxide electrodes during co-sintering at traditional sintering temperatures is introduced. Specifically, carbon templated samarium-doped ceria nanoparticles (nSDC) were successfully integrated with commercial lanthanum strontium cobalt ferrite (LSCF) and commercial SDC powders, producing LSCF-SDC-nSDC cathodes upon processing. The effect of nSDC concentration on cathode electrocatalytic activity was investigated at low operational temperatures, 600 °C–700 °C, with symmetrical cells. Low nSDC loadings, ≤5 wt% nSDC, significantly decreased cell polarization resistance whereas higher loadings increased it. The best electrochemical performance was achieved with 5 wt% nSDC, lowering the polarization resistance by 41% at 600 °C. Fuel cell tests demonstrate that adding 5 wt% nSDC increased the maximum fuel cell power density by 38%. Electrochemical impedance spectra showed substantial improvements in both fuel cell polarization resistance and ohmic resistance, indicating that nSDC increased the electrocatalytically active area of the cathode. This work demonstrates a simple, novel method for effectively increasing electrocatalytic activity of solid oxide electrodes at low operational temperatures.

scholarly journals Calcium manganite as oxygen electrode materials for reversible solid oxide fuel cell

2015 ◽  
Vol 182 ◽  
pp. 289-305 ◽  
Author(s):  
Chengsheng Ni ◽  
John T. S. Irvine
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Polarization Resistance ◽  
Electrode Materials ◽  
Electrochemical Impedance ◽  
Variable Temperature ◽  
Oxygen Electrode ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Electrochemical Impedance Spectra

For an efficient high-temperature reversible solid oxide fuel cell (RSOFC), the oxygen electrode should be highly active for the conversion between oxygen anions and oxygen gas. CaMnO3−δ (CM) is a perovskite that can be readily reduced with the formation of Mn3+ giving rise to oxygen defective phases. CM is examined here as the oxygen electrode for a RSOFC. CaMn0.9Nb0.1O3−δ (CMN) with Nb doping shows superior electric conductivity (125 S cm−1 at 700 °C) compared with CM (1–5 S cm−1 at 700 °C) in air which is also examined for comparison. X-ray diffraction (XRD) data show that CM and CMN are compatible with the widely used yttria-stabilized zirconia (YSZ) electrolyte up to 950 °C. Both materials show a thermal expansion coefficient (TEC) close to 10.8–10.9 ppm K−1 in the temperature range between 100–750 °C, compatible with that of YSZ. Polarization curves and electrochemical impedance spectra for both fuel cell and steam electrolysis modes were investigated at 700 °C, showing that CM presented a polarization resistance of 0.059 Ω cm2 under a cathodic bias of −0.4 V while CMN gave a polarization resistance of 0.081 Ω cm2 under an anodic bias of 0.4 V. The phase stability up to 900 °C of these materials was investigated with thermogravimetric analysis (TGA) and variable temperature XRD.

scholarly journals Differentiation and Decomposition of Solid Oxide Fuel Cell Electrochemical Impedance Spectra

2019 ◽  
Vol 35 (5) ◽  
pp. 509-516 ◽  
Author(s):  
Wangying SHI ◽  
◽  
Chuan JIA ◽  
Yongliang ZHANG ◽  
Zewei Lü ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Electrochemical Impedance ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Impedance Spectra ◽  
Electrochemical Impedance Spectra

Zn 0.6 Fe 0.1 Cu 0.3 / GDC Composite Anode for Solid Oxide Fuel Cell

2011 ◽  
Vol 8 (3) ◽  
Author(s):  
Rizwan Raza ◽  
Bin Zhu ◽  
Torsten H. Fransson
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Electrode Materials ◽  
Electrochemical Impedance ◽  
Research Effort ◽  
High Resolution Electron Microscopy ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Composite Anode ◽  
Electrochemical Impedance Spectra

Recent research results show that homogeneity and microstructure are very important parameters for the development of low cost materials with better performance for fuel cell applications. This research effort has been contributed in the development of low temperature solid oxide fuel cell (LTSOFC) material and technology as well as applications for polygeneration. The microstructure and electrochemical analyses were conducted. We found a series of new electrode materials which can run solid oxide fuel cell at 300–600°C range with high performances, e.g., a high power density output of 980 mW cm−2 was obtained at 570°C. The fuel cell electrodes were prepared from metal oxide materials through a solid state reaction and then mixed with doped ceria. The obtained results have many advantages for the development of LTSOFCs for polygeneration. The nanostructure of the anode has been studied by high-resolution electron microscopy, the crystal structure and lattice parameters have also been studied by X-ray diffraction. The electrical conductivity of the composite anode was studied by electrochemical impedance spectra.

Performance of Ba0.5Sr0.5Co0.8Fe0.2O3-δ-Ag Composite Cathode Materials for IT-SOFCs

2011 ◽  
Vol 311-313 ◽  
pp. 2309-2314 ◽  
Author(s):  
Wen Xia Zhu ◽  
Zhe Lü ◽  
Le Xin Wang ◽  
Xiao Yan Guan ◽  
Xin Yan Zhang
Keyword(s):  
Solid Oxide Fuel Cells ◽  
Electrochemical Impedance ◽  
Composite Cathode ◽  
Solid Oxide ◽  
Electrode Polarization ◽  
Impedance Spectra ◽  
Electrochemical Impedance Spectra ◽  
Composite Cathodes ◽  
Reduced Temperature ◽  
Resistance Value

°Abstract. In order to develop new cathodes for reduced temperature SOFCs, Ba0.5Sr0.5Co0.8Fe0.2O3-δ-Ag composite cathode was investigated in intermediate-temperature Solid Oxide Fuel Cells (IT-SOFCs). The XRD results suggested that no chemical reactions between BSCF and Ag in the composite cathode were found. The resistance measurements showed that the addition of Ag into BSCF improved electrical conductivity of pure BSCF, and the improved conductivity resulted in attractive cathode performance. In addition, electrochemical impedance spectra exhibited the better performance of BSCF-Ag composite cathodes than pure BSCF, e.g., the polarization resistance value of BSCF-Ag was only 0.36Ω cm2 at 650°C, which was nearly 80% lower than that of BSCF electrode. Polarization curves showed the overpotential decreased with the addition of Ag. The current density value of BSCF-Ag was 0.88Acm-2 under –120mV, about five times of that BSCF measured at 650°C. As a summary, compared to a pure BSCF cathode, it was found that adding Ag in the cathode enhanced the BSCF performance significantly.

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