Why solid oxide cells can be reversibly operated in solid oxide electrolysis cell and fuel cell modes?

2015 ◽  
Vol 17 (46) ◽  
pp. 31308-31315 ◽  
Author(s):  
Kongfa Chen ◽  
Shu-Sheng Liu ◽  
Na Ai ◽  
Michihisa Koyama ◽  
San Ping Jiang
Keyword(s):  
Fuel Cell ◽  
Operating Conditions ◽  
Solid Oxide ◽  
Electrolysis Cell ◽  
Electrolyte Interface ◽  
Solid Oxide Electrolysis ◽  
Solid Oxide Electrolysis Cell ◽  
Ysz Electrolyte

The LSM electrode/YSZ electrolyte interface of solid oxide cells is reversible under cyclic SOFC cathodic and SOEC anodic operating conditions.

scholarly journals 3D CFD Electrochemical and Heat Transfer Model of an Internally Manifolded Solid Oxide Electrolysis Cell

2011 ◽  
Author(s):  
Grant L. Hawkes ◽  
James E. O’Brien ◽  
Greg G. Tao
Keyword(s):  
Heat Transfer ◽  
Hydrogen Production ◽  
Current Density ◽  
Operating Conditions ◽  
Solid Oxide ◽  
Electrolysis Cell ◽  
Transfer Model ◽  
Gas Composition ◽  
Solid Oxide Electrolysis ◽  
Solid Oxide Electrolysis Cell

A three-dimensional computational fluid dynamics (CFD) and electrochemical model has been created to model high-temperature electrolysis cell performance and steam electrolysis in an internally manifolded planar solid oxide electrolysis cell (SOEC) stack. This design is being evaluated experimentally at the Idaho National Laboratory (INL) for hydrogen production from nuclear power and process heat. Mass, momentum, energy, and species conservation are numerically solved by means of the commercial CFD code FLUENT. A solid-oxide fuel cell (SOFC) model adds the electrochemical reactions and loss mechanisms and computation of the electric field throughout the cell. The FLUENT SOFC user-defined subroutine was modified for this work to allow for operation in the SOEC mode. Model results provide detailed profiles of temperature, operating potential, steam-electrode gas composition, oxygen-electrode gas composition, current density and hydrogen production over a range of stack operating conditions. Results will be presented for a five-cell stack configuration that simulates the geometry of five-cell stack tests performed at the INL and at Materials and System Research, Inc. (MSRI). Results will also be presented for a single cell that simulates conditions in the middle of a large stack. Flow enters the stack from the bottom, distributes through the inlet plenum, flows across the cells, gathers in the outlet plenum and flows downward making an upside-down “U” shaped flow pattern. Flow and concentration variations exist downstream of the inlet holes. Predicted mean outlet hydrogen and steam concentrations vary linearly with current density, as expected. Contour plots of local electrolyte temperature, current density, and Nernst potential indicate the effects of heat transfer, reaction cooling/heating, and change in local gas composition. Results are discussed for using this design in the electrolysis mode. Discussion of thermal neutral voltage, enthalpy of reaction, hydrogen production, cell thermal efficiency, cell electrical efficiency, and Gibbs free energy are discussed and reported herein.

High-performance electrodes for reversible solid oxide fuel cell/solid oxide electrolysis cell: Ni–Co dispersed ceria hydrogen electrodes

RSC Advances ◽  
2014 ◽  
Vol 4 (31) ◽  
pp. 16260 ◽  
Author(s):  
Ryuta Nishida ◽  
Pramote Puengjinda ◽  
Hanako Nishino ◽  
Katsuyoshi Kakinuma ◽  
Manuel E. Brito ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
High Performance ◽  
Solid Oxide ◽  
Electrolysis Cell ◽  
Oxide Fuel ◽  
Solid Oxide Electrolysis ◽  
Solid Oxide Electrolysis Cell

scholarly journals Thermal and Electrochemical Three Dimensional CFD Model of a Planar Solid Oxide Electrolysis Cell

2005 ◽  
Author(s):  
Grant Hawkes ◽  
Jim O’Brien ◽  
Carl Stoots ◽  
Steve Herring ◽  
Mehrdad Shahnam
Keyword(s):  
National Laboratory ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Solid Oxide ◽  
Cathode Side ◽  
Electrolysis Cell ◽  
Gas Composition ◽  
Cfd Model ◽  
Solid Oxide Electrolysis ◽  
Solid Oxide Electrolysis Cell

A three-dimensional computational fluid dynamics (CFD) model has been created to model high-temperature steam electrolysis in a planar solid oxide electrolysis cell (SOEC). The model represents a single cell, as it would exist in an electrolysis stack. Details of the model geometry are specific to a stack that was fabricated by Ceramatec, Inc. and tested at the Idaho National Laboratory. Mass, momentum, energy, and species conservation and transport are provided via the core features of the commercial CFD code FLUENT. A solid-oxide fuel cell (SOFC) model adds the electrochemical reactions and loss mechanisms and computation of the electric field throughout the cell. The FLUENT SOFC user-defined subroutine was modified for this work to allow for operation in the SOEC mode. Model results provide detailed profiles of temperature, Nernst potential, operating potential, anode-side gas composition, cathode-side gas composition, current density and hydrogen production over a range of stack operating conditions. Mean model results are shown to compare favorably with experimental results obtained from an actual ten-cell stack tested at INL.

scholarly journals Chromium deposition and poisoning of La0.8Sr0.2MnO3 oxygen electrodes of solid oxide electrolysis cells

2015 ◽  
Vol 182 ◽  
pp. 457-476 ◽  
Author(s):  
Kongfa Chen ◽  
Junji Hyodo ◽  
Aaron Dodd ◽  
Na Ai ◽  
Tatsumi Ishihara ◽  
...  
Keyword(s):  
Surface Segregation ◽  
Oxygen Electrode ◽  
Operating Conditions ◽  
Solid Oxide ◽  
Electrolysis Cell ◽  
Electrolyte Interface ◽  
Oxygen Electrodes ◽  
Inner Surface ◽  
Solid Oxide Electrolysis ◽  
Electrolyte Surface

The effect of the presence of an Fe–Cr alloy metallic interconnect on the performance and stability of La0.8Sr0.2MnO3 (LSM) oxygen electrodes is studied for the first time under solid oxide electrolysis cell (SOEC) operating conditions at 800 °C. The presence of the Fe–Cr interconnect accelerates the degradation and delamination processes of the LSM oxygen electrodes. The disintegration of LSM particles and the formation of nanoparticles at the electrode/electrolyte interface are much faster as compared to that in the absence of the interconnect. Cr deposition occurs in the bulk of the LSM oxygen electrode with a high intensity on the YSZ electrolyte surface and on the LSM electrode inner surface close to the electrode/electrolyte interface. SIMS, GI-XRD, EDS and XPS analyses clearly identify the deposition and formation of chromium oxides and strontium chromate on both the electrolyte surface and electrode inner surface. The anodic polarization promotes the surface segregation of SrO and depresses the generation of manganese species such as Mn2+. This is evidently supported by the observation of the deposition of SrCrO4, rather than (Cr,Mn)3O4 spinels as in the case under the operating conditions of solid oxide fuel cells. The present results demonstrate that the Cr deposition is essentially a chemical process, initiated by the nucleation and grain growth reaction between the gaseous Cr species and segregated SrO on LSM oxygen electrodes under SOEC operating conditions.

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