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Building Fuel Cells from Kits?
ItsMr.Data asks: "I am looking for a model fuel cell. After checking many web sites, and this one seems to have the best selection. I am wondering if, due to the high cost of the kits, any Slashdot readers have ever built their own fuel cells. I would also like to know if any readers have found any good resellers of kits and supplies."
That I've got a catalogue today with a fuel cell kit.
:-(
It's from an australian company, and it costs AUD299 so it's probably not much help - but it does look like some sort of generic kit. No specs on the cell though
You are in a twisty maze of processor lines, all alike.
There is a lot of hype here.
I've been meaning to get one for myself, but haven't yet found the time.
Fuel Cell Kit
A blog like any other.
http://froogle.google.com/froogle?scoring=p&q=%22f uel+cell%22+kit&btnG=Search+Froogle
Starting at $99.99, and in-stock at $140, there are reversible fuel-cell kit cars.
Most of the posters here are providing links to "toy" fuel cells, suitable for lab experiments and small robotic toys but vastly underpowered for real-world applications. So I searched a bit further and found the real thing.
Product brochure (PDF format) is here.
Click here for a search interface to various fuel-cell products and technologies.
The Web is like Usenet, but
the elephants are untrained.
Do you have proof of this? It sounds like complete bunk to me.
Wise default opinion... Even ignoring the economics of the situation (how do they sell a vehicle containing $100k worth of platinum for FAR under $100k?), such an assertion also ignores the requirements of such a fuel cell as well.
First of all, most "platinum" catalysts actually use palladium, still not cheap but a tenth the cost of actual platinum. Second, surface area means everything. The most common way of maximizing surface area of a catalyst involves using it as a componant of the surface of a ceramic material (such as in catalytic converters, which on average use less than a quarter of milligram of palladium). On a similar catalyst-density to a catalytic converter, even using real platinum rather than palladium, you would need a ceramic cube over 250 feet on a side to use up $100,000 worth of platinum).
Finally, even if this particular use required (for some strange reason) non-powdered metal, presenting a solid metalic surface - Making it into a foil bonded to some less expensive metal (copper, for instance) would give you (at least) 125 square feet of surface area. A thick electroplating could beat that by an order of magnitude.
So no, you should not believe it, without some totally irrefutable proof.
For this homebrew effort, I personally think that the "sacraficial anode" type of fuel cell is one that could be done most easily. In these types of fuel cells, a metal anode is decomposed in an electrolyte solution, and it is this decomposition that is used to convey the charges, thus creating the voltage potential. First, take a look at this link. This is from the fuel cell store website which was mentioned by the submitter. This link show a product that the store carries which is a sacraficial anode fuel cell. The anode in this case is magnesium-based, the electrolyte is salt water. The cathode is a so-called "diffusion cathode", which performs an oxygen-interface with the surrounding air, via a semi-permeable membrane. This membrane is such that oxygen is allowed in, but the salt water inside stays inside.
Now, this company that supplies this cell to the fuel-cell store gives a good explanation of what is going on. However, it is different from what I remember. I remember that they used to sell a different such fuel cell - one in which the sacraficial anode was alluminium, not magnesium. I can't remember what the chemical reaction was, but it was nearly identical to what goes on with the magnesium based cell. Seeing this, I realized that such a homebrew cell might be possible.
The question is, what to use for materials? Here's the answer I have come up with:
1. Get a piece of PVC pipe with an end cap. Drill a bunch of holes in it, in a pattern of some sort. The more holes, the better, but make sure it is left structurally sound. Install the end cap.
2. Construct a cardboard tube such that its diameter is approximately 1-2mm less than the inside diameter of the PVC pipe.
3. Around this cardboard tube wrap a single layer of stainless steel mesh cloth. Around this wrap a single layer of polyethylene or polypropylene plastic.
4. Slide this inside the PVC pipe. This is your diffusion cathode.
5. In the center of another end cap, attach an alluminium rod. This is your anode.
6. Fill the pipe with a mostly saturated-salt water solution. Insert alluminium rod and cap. The rod should not touch the sides, but instead should hang down the middle of the pipe. Keep the pipe vertical, leave room for air circulation.
7. Profit?
Now, I don't know if this will work. I have not tried it. But I think somewhere in it is gem of truth on how a homebrew fuel cell could be made. The hardest (and most expensive) portion of a fuel cell is the membrane. I think something like cling wrap or plastic freezer could supply the membrane - some kind of plastic that "breaths", and lets air through.
So, could a homebrew fuel cell be made? Try it, and see!
Reason is the Path to God - Anon