Artur Braun, Sir, I want to check what effect it has on the ceramic electrolytes. Then i will proceed accordingly.

Because most of the researcher dont used graphene for SOFC due to higher operating temperature.

Artur Braun because it increases conductivity.

Of course you can use graphene effectively for electrolyte in SOFC which can yield a higher power density. Graphene oxide (GO) is used in fuel cells now a days for relatively high proton conduction even at low relative humidity and temperatures.

Gourab Das Thank you so much for answering.

Yes, you are right, but I read that graphene will evaporate when used at certain operating temperatures (May be more than 600 C). However, the ceramic electrolyte is sintered at a higher working temperature ( more than 1200- 1500 C). So, if we use graphene in the electrolyte and sintered it at a higher temperature, so that the graphene will evaporate and leave some porosity in it, what do you think about it.

What you say can about it, maybe I am wrong in some aspects, please guide me.

Thank you

What are the advantages to used Graphene In this field comparing with common metal?

good luck

regards

Raad

Artur Braun Sir, Yes you are right.

Graphene/Go/rGo also affects the SOFC electrolyte performance. It has a great influence on the grain boundaries as well. Just trying to get useful information from all researchers who already worked on it.

Thank you so much for your concern.

Are the work is looking by graphene for offers more ionization or to protect the electrodes .

Dear M Bilal Hanif ,

why/how it increases (ionic) conductivity?

Dear Ioannis Samaras Sir, I think it will not increase the ionic conductivity. But it will foresure increase the electronic conductivity up to some extend.

but there are some other factors that may effect by adding graphene/ Go/ rGO. thats why i am asking why people considered its not a good choice for solid oxide fuel cell applications

Dear M Bilal Hanif ,

a(ny) high (partial) electronic[1] conductivity in (SOFC) electrolytes is a very common, historical, experimental error (trap).

1. Your (partial quotation): "... But it will foresure increase the electronic conductivity..."

Yes Ioannis Samaras Sir you are right. I understand what you are trying to say.

Thank you so much for your guidance

Ioannis Samaras Sir, what is your opinion on this, will it affect the densification of the electrolyte?

Dear M Bilal Hanif ,

it might affect the densification of your electrolyte. Try to test it, experimentally.

It is great useful to fellow this discussion .

Dear Ioannis Samaras Sir, Thank you so much for valuable comments.

i will foresure try this experimentally and will let you know about the details.

thank you so much for joining my discussion.

Dear Raad Sh. Alnayli Sir, thank you so much for joining our discussion.

Stay blessed

Dear M Bilal

There’s a huge interest in replacing the liquid electrolytes in current batteries with ceramic materials because they’re safer and can provide higher energy density, so far, research on solid electrolytes has focused on optimizing their chemical properties. Liquid electrolytes are found in most batteries but at high currents, tiny filaments of lithium metal can form inside the electrolytes, which cause batteries to short circuit. Liquid electrolytes are highly flammable, so shorting can lead to fires. Solid ceramic electrolytes are not flammable, and evidence suggests they can prevent the formation of lithium filaments, which could enable batteries to operate at higher currents. However, ceramics are highly brittle materials that can fracture during the manufacturing process and during use. So, the researchers wanted to see if infusing a ceramic with graphene could increase the material’s ability to withstand cracking without falling apart while maintaining the electronic properties needed for electrolyte function. Experiments showed that the graphene did not interfere with the electrical properties of the material. According to research work, the key was making sure the right amount of graphene was added to the ceramic. Too little graphene would not achieve the toughening effect, but too much would cause the material to become electrically conductive. as we want the electrolyte to conduct ions, not electricity, so the graphene is a good electrical conductor, so people may think we’re shooting ourselves in the foot by putting a conductor in our electrolyte. But if we keep the concentration low enough, we can keep the graphene from conducting, and we still get the structural benefit.

Regards

Dear M. S. Alkathy you explained it very well.

thank you so much for explaining everything.

stay blessed

Hello,

I think graphene-based materials have no potential application in the SOFC's electrolyte.

There are some requirements that needed to be considered for the SOFC’s electrolyte:

1) Having high oxygen ion conductivity

2) Being electrical insulator to minimize the internal electrical leakage

3) Being stable under the oxidation and reduction condition of the fuel cell

4) Being stable under the operating temperature of SOFC as well as its processing (sintering) condition

5) Have a dense structure to prevent the gas leakage

For graphene, it has almost no oxygen ion conductivity, it shows high electrical conductivity, it is very difficult to densify graphene-ceramic composite, and it is not very stable under high oxidation condition as well as high operation and processing temperature. These problems will be intensified for the fabrication of thin (around 10µm) electrolyte films.

If you are looking for improvement in the electrolyte toughness, applying other techniques can be more effective. For example, YSZ with 3% Yttria enjoys high toughness and fair oxygen ion conductivity while YSZ with 8% Yttria has high oxygen ion conductivity with fair mechanical properties. A combination of these two grades of YSZ can provide relatively high oxygen ion conductivity and good toughness. If you are looking for a sintering aid, again, graphene-based materials may not be a good choice because of their covalent bands (even if the sintering at a high temperature can be addressed).

GO is an appropriate additive for the medium temperature (80 - 120⁰C) Proton Exchange Membrane (PEM) because of its high proton conductivity and ability to preserve water in its structure at the relatively dry condition. Graphene also has a potential application for the catalyst support of PEMFC because it is more stable than carbon black under the oxidation condition. However, to my best knowledge, they are not good candidates for using in SOFC.

In order to develop the electrical properties

Dear Dr, Alnayli,

May I ask you to explain more about "developing the electrical properties"? To my knowledge, the electrolyte should be insulator (for the electron conduction) as you can find this requirement in the following resources:

1) Minh, Nguyen Quang, and Takehiko Takahashi. Science and technology of ceramic fuel cells. Elsevier, 1995. (Chapter 4)

2) Singhal, Subhash C., and Kevin Kendall, eds. High-temperature solid oxide fuel cells: fundamentals, design and applications. Elsevier, 2003. (Chapter 4)

Enhancement the electrical conductivity (if it is low) causes increasing the internal current leakage leading to reduction of OCV and the output power. At high electrical conductivity, the short circuit can be taken place. Even one of the drawbacks of doped Ceria is its inherent high electronic conductivity.

My knowledge may not be up to date in this field, so If you have any new resources which show electrical conductivity to some extend can improve the performance of SOFC, please share them with us.

Thank you,

Raad Sh. Alnayli

It is little bit strange that one can mix ceramics with graphene to enhance its mechanical properties without affecting its electronic conduction properties.

By definition graphene is a two dimensional graphite layer having high electron conductivity. Then how can you introduce graphene and at the same time hold the electronic conduction negligible?

How you introduce graphine layers inside the ceramic.

Then if you want to mix them most probably you mean carbon and ceramic.

There is contradiction in this question. And according to the basic definition of the

graphene this process of mixing will not lead to the expected materials properties.

Best wishes