Making a PEM fuel cell

[Muzzwezz]

Hi, for my design A2 project i have set about the task of building a PEM hydrogen fuel cell, i wish for it to run around 2-3 watt power output preferably, or at the least for it to power an LED or Motor.

 

To start i researched PEMs and so have many a-question, but ill start with my practice set-up:

 

Electrodes: Aluminum

Water: Tap

Power: 9.4 Volt 190mA 1.7 watts DC

[add: ht-tp:// to beginning of following links, dam anti spamming]

i12.photobucket.com/albums/a239/muzzwezz/PICT0013.jpg

 

i12.photobucket.com/albums/a239/muzzwezz/PICT0016.jpg

 

i12.photobucket.com/albums/a239/muzzwezz/PICT0019.jpg

 

From this experiment it took around three hours to get around 3cm3 of hydrogen, and 1.5 of O2 [at a guess]. I assume this is due to many factors, in which i intend to inquire,

 

First, electrodes - I used aluminum which i am the first to admit wasn't the best of choices, but its what i had,

What electrodes would you suggest? - Some say platinum and i say im a poor student,

Carbon / Graphite - this seems to break up / dissolve at a fast rate meaning you'll have to keep replacing them

I read someone saying nickle

[add ht-tp:// to following link]

hypography.com/forums/chemistry/4164-nickel-catalyst-pem-fuel-cell.html

I assume that this is alot cheaper, but seem not to be-able to find a site that sells it in sheet/foil of around 4 inches cubed.

What do you recommend using as electrodes and preferably a link to buy it too

 

Next: Electrolyte

Water, if you look at the PEM toys,

[add ww-w.]

minihydrogen.dk

They all say to use Distilled water, but according to:

jchemed.chem.wisc.edu/JCeSoft/CCA/CCA3/MAIN/ELECSOL/PAGE1.HTM

"In the absence of dissolved electrolytes, water will not conduct electricity, so no electrolysis occurs" and so it shouldn't be possible to split up the molecules? is this correct

Also most places say i should use Niflon and an electrolyte;

The gas was stored in two inverted glasses, was it constantly also reverting back to water as i was making it? explaining the slow gas production? and so does an electrolyte like Niflon prevent this? Else is Niflon essential as i got power out, or does it just speed up the creation of electricity and Gas?

 

 

Power source:

I used 9.4 volt 190 mA 2 watt power source, as that is what was available, is just using a 9 volt square battery better? is there a maximum voltage / Amperage recommended.

 

Distance of electrodes, does this effect the speed of reaction? the closer the faster i would assume?, and any other factors that would allow me to get a faster amount of gas

 

Electricity output:

When finished i removed the aluminum and power, then just put two bared copper wires into each glass and connected it across an old volt meter off an old radio. The end of the wires were completely submerged - as in the ends weren't in the gas, if the actual copper was in the oxygen and Hydrogen gas rather than in the water would this increase my power output?

 

I managed to get a power output, how much i dont know, but very little, the voltmeter is marked very strangely and i have a horrible feeling i never got past 20 mV and unknown ampage, before i could try out an LED i accidentally lost my hydrogen

 

So if you could decipher the text above and answer any of the questions it would be a great help!, thanks

 

Dom :)

[Muzzwezz]

s12.photobucket.com/albums/a239/muzzwezz/?action=view&current=PICT0023.flv

 

add ht-tp:// to watch a very poor quality video of the experiment, lighting's all wrong,

 

another point is that the bubbles of O and H stick to the electrodes, thus meaning less space is available to electonisize, is there any way to get around this problem, does it happen with other electrodes?

[Mercedes Benzene]

Well... you're on the right track.

I would suggest carbon electrodes. They *shouldn't* break up when passing a current through them. I've never seen that happen before.

Nickel electrodes can be found here:

http://secure.sciencecompany.com/Electrode-Strips-C667.aspx

...but I definitely suggest Carbon.

 

As for electrolytes, yes. You should use some. Water is a terrible conductor by itself. A simple metallic salt will solve this problem. It's your choice, but table salt is easy enough. :)

 

For your power source, make sure you're using DC current.

See our thread on this subject here:

http://hypography.com/forums/chemistry/5332-ac-electrolysis.html

 

Good luck! and feel free to ask any more questions if necessary.

[Muzzwezz]

thank-you Merc, yes its definitely DC voltage, actually it says explicitly it should only be used to charge Li-iron batteries :)

 

I said that about carbon as i remember us doing it in chem in As, and it broke up, maybe i was dreaming at the time though

 

 

You also mentioned using table salt, or NaCl, this i believe produces chlorine gas when split, which is very nasty stuff - are you sure it works?

 

ill look into using other electrolytes, thanks for the input!!!

[Mercedes Benzene]

You also mentioned using table salt, or NaCl, this i believe produces chlorine gas when split, which is very nasty stuff - are you sure it works?

 

:) It's not very likely that you'll get any chlorine gas. The bond between sodium and chlorine is quite strong, and only an extremely high current and voltage will split it (and this is after the NaCl is molten!). If you're worried, just make sure you replenish the water regularly.

[Muzzwezz]

Seems now ive added about 1 tspn of salt that when i try and get power back from the cell i cant,

 

also noticed i seem not to be gaining much 0, a noticeable amount of H had appeared and yet apart from the bubbles on the anode no O has appeared or captured in the glass. Ill post anther pic

[Muzzwezz]

The Rig:

i12.photobucket.com/albums/a239/muzzwezz/PICT0007-1.jpg

 

Before Salt:

i12.photobucket.com/albums/a239/muzzwezz/PICT0006-1.jpg

 

After salt:

i12.photobucket.com/albums/a239/muzzwezz/PICT0009-1.jpg

 

again just add ht-tp://

[Mercedes Benzene]

Well it's hard to come to any conclusions by simply looking at those pictures. I would say keep trying, and give us as much detail as possible.

[Muzzwezz]

if i had my power out terminals both in the gas and not touch either the electrodes or water would that make it better or worse?

[Mercedes Benzene]

if i had my power out terminals both in the gas and not touch either the electrodes or water would that make it better or worse?

 

Sorry, but I don't understand the question...

 

What do you mean by "both in the gas" and "not touch either the electrodes or water"?

:)

[Muzzwezz]

lol sorry let me refrase

 

I have two power inputs, each going to the aluminium

Then above that are the two inverted glasses

 

I then have two separate Copper wires which connect to the voltmeter

 

At the moment i have been placing the copper voltmeter wires directly into the water and seem to be getting a current

 

would this improve if the copper wire was placed in the gas at the top of the glasses rather than in the water surrounding the electrodes?

 

 

if that makes sense?

[HydrogenBond]

One useful approach to electrode effeciency is to increase its surface area. One way this can be done is with carbon filaments woven into cloth. Even if you use aluminum, use thin wire twisted tightly at the top (for good conduction contact) but loosely where it enters the solution. The surface area will increase by an order of magnitude or more.

[Muzzwezz]

Hello

 

I am trying to make a PEM using Nafion 112, however i am unsure on several things:

 

Firstly i have only found Untreated Nafion 112 to buy:

fuelcellstore.com/cgi-bin/italy/view=Item/cat=57/product=238

 

For my PEM to work do i need to treat it?

If so how do you treat it?

Or could you direct me to a site that sells pretreated membrane?

 

Many regards

Dominic

[Muzzwezz]

Does anyone know where to buy cheap and small quantities of Nafion 112?

 

i was looking at:

 

http://www.fuelcellstore.com/cgi-bin/italy/view=Item/cat=57/product=238

 

but it costs 75$ just to ship it!!

 

preferably in the UK.

 

thanks