Electrochemical Performance of Ni-YSZ, Ni/Ru-GDC, LSM-YSZ, LSCF and LSF Electrodes for Solid Oxide Electrolysis Cells

2010 ◽  
Author(s):  
P. Kim-Lohsoontorn ◽  
H.-B. Yim ◽  
J.-M. Bae
Keyword(s):  
Electrochemical Performance ◽  
Operating Conditions ◽  
Solid Oxide ◽  
Hydrogen Electrode ◽  
Anodic Reaction ◽  
Oxygen Electrodes ◽  
Electrolysis Cells ◽  
Solid Oxide Electrolysis ◽  
Solid Oxide Electrolysis Cells ◽  
Electrolysis Mode

The electrochemical performance of solid oxide electrolysis cells (SOECs) having nickel – yttria stabilized zirconia (Ni-YSZ) hydrogen electrode and a composite lanthanum strontium manganite – YSZ (La0.8Sr0.2MnO3−δ – YSZ) oxygen electrodes has been studied over a range of operating conditions temperature (700 to 900°C). Increasing temperature significantly increased electrochemical performance and hydrogen generation efficiency. Durability studies of the cell in electrolysis mode were made over 200 h periods (0.1 A/cm2, 800°C, and H2O/H2 = 70/30). The cell significantly degraded over the time (2.5 mV/h). Overpotentials of various SOEC electrodes were evaluated. Ni-YSZ as a hydrogen electrode exhibited higher activity in SOFC mode than SOEC mode while Ni/Ru-GDC presented symmetrical behavior between fuel cell and electrolysis mode and gave lower losses when compared to the Ni-YSZ electrode. All the oxygen electrodes gave higher activity for the cathodic reaction than the anodic reaction. Among the oxygen electrodes in this study, LSM-YSZ exhibited nearest to symmetrical behavior between cathodic and anodic reaction. Durability studies of the electrodes in electrolysis mode were made over 20–70 h periods. Performance degradations of the oxygen electrodes were observed (3.4, 12.6 and 17.6 mV/h for LSM-YSZ, LSCF and LSF, respectively). The Ni-YSZ hydrogen electrode exhibited rather stable performance while the performance of Ni/Ru-GDC decreased (3.4 mV/h) over the time. This was likely a result of the reduction of ceria component at high operating voltage.

Electrochemical Performance and Microstructural Characterization of Solid Oxide Electrolysis Cells

2011 ◽  
Vol 287-290 ◽  
pp. 2506-2510 ◽  
Author(s):  
Jian Xin Zhu ◽  
Bo Yu
Keyword(s):  
Fuel Cell ◽  
Hydrogen Production ◽  
Electrochemical Performance ◽  
High Efficiency ◽  
Solid Oxide ◽  
Hydrogen Electrode ◽  
Steam Content ◽  
Electrolysis Cells ◽  
Solid Oxide Electrolysis ◽  
Solid Oxide Electrolysis Cells

High temperature steam electrolysis (HTSE) through solid oxide electrolysis cells (SOEC), a promising high-efficiency and zero-emission way to large-scale hydrogen production, has been received increasingly international interest. The hydrogen production efficiency of HTSE is more than 50%. In this paper, the electrochemical performance and microstructure change of single button cells operating in both fuel cell (SOFC) and electrolysis modes (SOEC) were studied at 850°C. Also, the degradation mechanisms of hydrogen electrodes were investigated. The results showed that OCV decreased from 0.944 V to 0.819 V when the steam content increased from 20% to 80%. The voltage began to increase rapidly at relatively higher current density for lower steam content because of steam starvation; however, steam starvation did not occur at higher steam content. The ASR data decreased from 1.68 to 0.645Ωcm2 with the increase of steam contents, while steam content had little effect on ASR data in SOFC mode. The polarization loss of the single cell was higher in electrolysis mode than that in fuel cell mode. The microstructure of the hydrogen electrode changed obviously after electrolysis process. Furthermore, the performance degraded at high steam partial pressure due to the oxidation of Ni grains at the interface of hydrogen electrode.

Sr2Fe1.5Mo0.5O6-δ- Zr0.84Y0.16O2-δMaterials as Oxygen Electrodes for Solid Oxide Electrolysis Cells

Fuel Cells ◽  
2014 ◽  
Vol 14 (6) ◽  
pp. 1046-1049 ◽  
Author(s):  
J. Li ◽  
C. Zhong ◽  
X. Meng ◽  
H. Wu ◽  
H. Nie ◽  
...  
Keyword(s):  
Solid Oxide ◽  
Oxygen Electrodes ◽  
Electrolysis Cells ◽  
Solid Oxide Electrolysis ◽  
Solid Oxide Electrolysis Cells

3-Dimensional Numerical Analysis of Solid Oxide Electrolysis Cells (SOEC) Steam Electrolysis Operation for Hydrogen Production

2014 ◽  
Author(s):  
Juhyun Kang ◽  
Joonguen Park ◽  
Joongmyeon Bae
Keyword(s):  
Simulation Model ◽  
Electrical Energy ◽  
High Energy ◽  
Operating Conditions ◽  
Solid Oxide ◽  
Governing Equations ◽  
Electrolysis Cells ◽  
Solid Oxide Electrolysis ◽  
Solid Oxide Electrolysis Cells ◽  
The Relationship

Hydrogen is a resource that provides energy and forms water only after reacting with oxygen. Because there are no emissions such as greenhouse gases when hydrogen is converted to produce energy, it is considered one of the most important energy resources for addressing the problems of global warming and air pollution. Additionally, hydrogen can be useful for constructing “smart grid” infrastructure because electrical energy from other renewable energy sources can be stored in the form of chemical energy by electrolyzing water, creating hydrogen. Among the many hydrogen generation systems, solid oxide electrolysis cells (SOECs) have attracted considerable attention as advanced water electrolysis systems because of their high energy conversion efficiency and low use of electrical energy. To find the relationship between operating conditions and the performance of SOECs, research has been conducted both experimentally, using actual SOEC cells, and numerically, using computational fluid dynamics (CFD). In this investigation, we developed a 3-D simulation model to analyze the relationship between the operating conditions and the overall behavior of SOECs due to different contributions to the over-potential. All SOECs involve the transfer of mass, momentum, species, and energy, and these properties are correlated. Furthermore, all of these properties have a direct influence on the concentration of the gases in the electrodes, the pressure, the temperature and the current density. Therefore, the conservation equations for mass, momentum, species, and energy should be included in the simulation model to calculate all terms in the transfer of mass, heat and fluid. In this simulation model, the transient term was neglected because the steady state was assumed. All governing equations were calculated using Star-CD (CD Adapco, U.S). The source terms in the governing equations were calculated with in-house code, i.e., user defined functions (UDF), written in FORTRAN 77, and these were linked to the Star-CD solver to calculate the transfer processes. Simulations were performed with various cathode inlet gas compositions, anode inlet gas compositions, cathode thickness, and electrode porosity to identify the main parameters related to performance.

scholarly journals REBaCo2O5+δ (RE = Pr, Nd, and Gd) as promising oxygen electrodes for intermediate-temperature solid oxide electrolysis cells

RSC Advances ◽  
2017 ◽  
Vol 7 (27) ◽  
pp. 16332-16340 ◽  
Author(s):  
Shaoming Liu ◽  
Wenqiang Zhang ◽  
Yifeng Li ◽  
Bo Yu
Keyword(s):  
Double Perovskite ◽  
Solid Oxide ◽  
Intermediate Temperature ◽  
Oxygen Electrodes ◽  
Electrolysis Cells ◽  
Solid Oxide Electrolysis ◽  
Solid Oxide Electrolysis Cells

Double-perovskite REBaCo2O5+δ (RE = Pr, Nd, and Gd) oxides were synthesized and evaluated as oxygen electrodes for intermediate-temperature solid oxide electrolysis cells (IT-SOECs).

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