[tom_miya2003]

1. Area: SOFC (solid oxide fuel cells)

2. Topic: No leakage currents in the doped Ceria electrolytes using in
SOFC.

3. Experimental Evidence:
Using SDC (Samaria doped Ceria) electrolytes, the OCV (open circuit
voltage) is only 0.8 V and lower than Nernst voltage 1.15V. If there
are any leakage currents in SDC electrolytes, the OCV should be
changed in long term experiments. There are not only ohmic loses, but
also polarization voltage losses. And the polarization voltage losses
should be changed, because every electrode becomes worse with time.
There are no perfect electrodes. But the OCV was constant 0.8V
permanently with rapidly aggregating anode. Why could the OCV be
constant while the anode getting worse with time?

Consequently, there are no leakage currents in Samaria doped Ceria.

Details are shown in next homepage.
Homepage: http://uk.geocities.com/tom_miya2003

{touch up; EE}

[trespam]

$this->bbcode_second_pass_quote('tom_miya2003', '1'). Area: SOFC (solid oxide fuell cells)

2. Topic: No leakage currents in the doped Ceria electrolytes using in
SOFC.

3. Experimental Evidence:

[Permanently_Baffled]

You better send this info to Bush he may want a refund on the multiple billions he has just signed off for fuel cell research!

[big_rc]

SOFCs are small change. PEM (Polymer Electrolyte Membrane) fuel cells are the "fuel cells" that everyone talks about when they say fuel cells in the media. SOFCs run at ~600C so they tend to be a bit hard to deal with. Also they are mainly designed for on-site power generation and not really a big commercial product. PEMs are the ones that people want to stick into cars and low temp applications and run on hydrogen. (Ballard's fuel cells are PEMs).

Open circuit voltage is independent of electrode performance. The most important thing to look at is the power curve at a specified voltage. If the power drops like a rock, then you have a much bigger problem than if the OCV drops.

[nero]

SOFCs certainly have some nice features (high efficiency useful hitemp heat energy, clean burning, no external reformation, no expensive catalyst ). Although as a transportation device I don't think they work because there would be too much temperature cycling required which might shorten the life of the stack. But used as a distributed power plant I like them alot. PEMs have their advantage and problems as well. Not terrible efficient, water balance problem, external reformation, low temperature heat management, ageing of membrane, expensive catalyst, poisoning of catalyst.

I've got a question for the original poster. can you explain what you believe is the significance of no current leakage at open circuit(To a non expert). It is not obvious to me what you are on about.

[tom_miya2003]

Q1. People want to stick into cars and low temp applications and run on hydrogen
Q2. As a transportation device I don't think they work

How will you get hydrogen?
It is too expensive to get from water electrolysis in usual temperature.
Then there needs SOFC technologies.

Q3. Open circuit voltage is independent of electrode performance.
Q4. Can you explain what you believe is the significance of no current leakage at open circuit(To a non expert).Open circuit voltage is independent of electrode performance.

Using doped Ceria electrolytes, in the conventional theory, RI-drop is caused by leakage (ionic and electronic) currents. So,

Open circuit voltage = Nernst voltage - RI-dorop - polarization voltage losses (1)

And polarization voltage losses are caused by leakage currents.
Polarization voltage losses are not independent of electrode performance.
So open circuit voltage is not independent of electrode performance

Q5. Can you dumb it down a bit?
I notice that there are no reports in the world about the changing in open circuit voltage using doped Ceria electrolytes.
Voltage loss should be caused by any other reasons.
Title should be “HUGE FLAW in SOLID STATE ELECROCHEMISTRY”.
One of the main principles in this area is denied.
We must rewrite present text books entirely. (for example, CRC Handbook of Solid State Electrochemistry)

[nero]

As I understand it:
Polarization loss is due to mass transport limitations between catalyst surface and bulk fluid. In an OC situation there would be little if any polarization so this term would be negligible?

If the resistance is a massive number the current may be negligible and result in a negligible polarization term while the RI term is still significant.

So in my thinking your equipment might not have been sensitive enough to pick up the small polarization caused by leakage. If you can't pick up the polarization term then the increase of the polarization term due to degredation of the catalyst performance will escape your notice as well.

(It's been a while so I'm probably missing something.)

[The_Virginian]

Now I know how useless that psych degree is. :D

Tom,

if that's your Idea of dumbing it down, could you please put it into street slang, either Ebonics/jive, "Scat" or Redneck, I am fleunt in those toungs.

( I do realize we are talking about voltage loss but as "Scotty" said "She can't do any mo' captain." )

[nicklockard]

$this->bbcode_second_pass_quote('The_Virginian', ':')oops: Now I know how useless that psych degree is. :D

Tom,

if that's your Idea of dumbing it down, could you please put it into street slang, either Ebonics/jive, "Scat" or Redneck, I am fleunt in those toungs.

( I do realize we are talking about voltage loss but as "Scotty" said "She can't do any mo' captain." )

[MonteQuest]

I own a some stock in Ballard Power, the leading fuel cell company. Trades at about $6/share nowadays, but in its pre-tech stock crash days it hit $119/share. I sold most near the peak.

http://www.ballard.com/

You guys seem to have a handle on this thread. What do you think about what they are doing?

[giengrene]

Monte,

Quick sell all your shares, hydrogen is a scam.

[The_Virginian]

Nick,

Happy to oblige. Yes! I was thinking of othe lady who played June Cleaver and the Jive/Airplane scene...(classic movie)

Unfortunately it was an Earnest (knowaddamean) cry for help that was not answered by our more technicaly minded friends here at Peak Oil.Com .

So if any of your real smart types would like to build bridges with us simple Volk, well go right on ahead and explain the first 5 posts.

[MonteQuest]

$this->bbcode_second_pass_quote('giengrene', 'M')onte,

Quick sell all your shares, hydrogen is a scam.

[giengrene]

Hydrogen fuel cells have many issues.

A) Electrolysis is inefficient and wasful of huge amounts of fresh water (no seawater won't work).

B) Hydrogen of the "future" will be made from Natural Gas...hmmm sounds like a fossil fuel to me. (otherwise it won't even compete w/ regular desiel)

C) Eficiency claims may be overstated (see first post). If someones calims are too good to be true, they generaly are.

D) Platinum is EXPENSIVE and won't get any cheaper. So unless your co. has really neet alternatives to Platinum I sugest you wait for a spike then sell.

I hope this explanation was effacious to "Virginian" as well.

[tom_miya2003]

My apology
I want to change my topic title, but I can not do it.

New Topic Name: Low Open Circuit Voltage in PEMs and SOFCs …Why?

Between SOFCs (solid oxide fuel cell) and PEMs (proton exchange membrane), using materials, temperature and carriers are different, but the electrochemical basic structure is almost same.

And in SOFCs and PEMs, open circuit voltage often become lower than Nernst voltage.

Why?

My answer: THERE SHOULD BE NEW TYPE POLARIZATION.

SOFC researchers do not agree with new type polarization.
Because they do not want to deny leakage currents which have not been measured.

When membranes have mixed ionic and electronic conductivity only near the cathode in PEMs, the electrochemical situation is same with doped Ceria electrolyte in SOFC.
So I hope that PEM researchers have interests in my topic.

About new type polarization, I added the detail explanation in my home page.
homepage: http://uk.geocities.com/tom_miya2003

[Sololeum]

G'Day All,

The problem with hydrogen is not esoteric -

It is not the significant loss of energy in making it.
It is not that it is only an expensive battery for an electric car.
It is not the very limited range that compressed hydrogen can give.
It is not the further loss of energy converting to liquid hydrogen.
It is not the danger of exploding hydrogen in traffic accidents.

BUT IT IS the very real danger we will kill ourselves and the entire planet through the loss of the ozone layer.

In the real world gas escapes, be it when you make it, when you fuel up, when you pipe it across the nation, when there are auto accidents, when it gets old, when the vehicle is on the scrap heap.

It is very simple - hydrogen escapes and goes up- and up - hits the ozone layer and converts to water, falls to earth and life on the planet is not possible.

With our experiences and our common knowledge of them including nuclear problems, and green house climate change, we can abstract the problem a little and say that man has to stop fooling around with unnatural systems and live within the framework of the planetary systems.

ie. If you want a fuel you grow it.

In Vi Et Silva

[Devil]

$this->bbcode_second_pass_quote('Sololeum', '
')It is very simple - hydrogen escapes and goes up- and up - hits the ozone layer and converts to water, falls to earth and life on the planet is not possible.

[tom_miya2003]

$this->bbcode_second_pass_quote('nero', 'A')s I understand it:
Polarization loss is due to mass transport limitations between catalyst surface and bulk fluid. In an OC situation there would be little if any polarization so this term would be negligible?

If the resistance is a massive number the current may be negligible and result in a negligible polarization term while the RI term is still significant.

So in my thinking your equipment might not have been sensitive enough to pick up the small polarization caused by leakage. If you can't pick up the polarization term then the increase of the polarization term due to degredation of the catalyst performance will escape your notice as well.

[big_rc]

Tom,

I think this might answer your question.

Typical OCV for PEM fuel cells (H2) are always going to be below the Nerst value because of one main reason.

Fuel crossover - There will be a small amount of fuel that leaks across the membrane from the anode to the cathode which will lower the OCV.

When you actually start to draw current is when item like mass transport become critical.

I don't know if this helps.