Hi there,

As mentioned before, the electrodes have to display sufficient ionic and electronic conductivities. This can be done either by mixing 2 materials each presenting one type of conductivity, or by using MIEC materials (mixed ionic and electronic conductors). The electrolyte should stick to only ionic conductivity, to preserve high faradaic efficiency, although Virkar showed that introducing small amount of electronic conductivity in the electrolyte could basically help prevent some forms of degradation.

Another important feature is the thermal expansion coefficients of all the layers that must be compatible. If not, it leads to high stresses over time and ultimately one layer will separate. The delamination of the oxygen electrode is usually considered as the most severe mechanism for cell degradation.

Also, the chemical stability of layers in contact must be demonstrated, as well as the chemical stability of each layer over time. For example, YSZ in Ni-YSZ has been shown to change from a cubic to a less conductive tetragonal crystal structure. Or the growth of an insulating phase between YSZ and LSCF, that led to the introduction of CGO barrier layers.

And of course, the materials have to display sufficient catalytic activity to participate in the electrochemical reactions.

These are the basic features for SOFC/SOEC materials. I'm sure there are more, but I gotta run ! Good luck.

Hi,Pardeep

I am also a newbie for SOFC. It is great to find someone that is in this research field here. Depending on the component that you are investigating, anode, cathode, electrolyte or the interconnecting materials. They require different types of properties.

Generally, electronic contribution is important but depending on which components that you are focusing. Such as anode, main material should be high catalytic and high dissolution when react with H2 or any other gasses. The material should be also metallic for electron conduction so that it completes the circuit back to cathode. Electrolytes needs higher ionic conduction to transfer oxide ion to anode from cathode . Though some of the materials possess mixed ionic electronic conductivity, it depends on which type of component that u are concern. And many studies regarding the different types of parameters and operating condition. Other that that, conductivity, impedance testing, single cell testing will be the main research interest nowadays. This field is seriously wide and many interesting knowledge can be explored. 

Dear Hoga, 

Its really nice, but I can not understand the meaning of " on which component that you are focusing" What are the components??  Can you suggest/send a review to read the basics on SOFC. 

Hi, 

Below are some of the review papers that I feel suitable for understanding the basics of SOFC. The basic components of SOFC include:- anode, electrolytes and cathodes.  You will also have other components such as the interconnect and sealing material

http://www.sciencedirect.com/science/article/pii/S136403210200014X

http://www.sciencedirect.com/science/article/pii/S0167273800004525

http://www.sciencedirect.com/science/article/pii/S1359645403004737 

http://www.sciencedirect.com/science/article/pii/S1364032112006430

Hello Pardeep:

I recommend reading at least the first chapters of this book. Here the basic characteristics and why each of the components listed SOFC

John T. S. Irvine • Paul Connor Editors

"Solid Oxide Fuels Cells: Facts and FiguresPast, Present and Future Perspectives

for SOFC Technologies".

Springer-Verlag London 2013

Hi there,

As mentioned before, the electrodes have to display sufficient ionic and electronic conductivities. This can be done either by mixing 2 materials each presenting one type of conductivity, or by using MIEC materials (mixed ionic and electronic conductors). The electrolyte should stick to only ionic conductivity, to preserve high faradaic efficiency, although Virkar showed that introducing small amount of electronic conductivity in the electrolyte could basically help prevent some forms of degradation.

Another important feature is the thermal expansion coefficients of all the layers that must be compatible. If not, it leads to high stresses over time and ultimately one layer will separate. The delamination of the oxygen electrode is usually considered as the most severe mechanism for cell degradation.

Also, the chemical stability of layers in contact must be demonstrated, as well as the chemical stability of each layer over time. For example, YSZ in Ni-YSZ has been shown to change from a cubic to a less conductive tetragonal crystal structure. Or the growth of an insulating phase between YSZ and LSCF, that led to the introduction of CGO barrier layers.

And of course, the materials have to display sufficient catalytic activity to participate in the electrochemical reactions.

These are the basic features for SOFC/SOEC materials. I'm sure there are more, but I gotta run ! Good luck.

Thank you, guys. As a newbie in SOFC, I learned some basic concepts here.