Graphite-Paper - Aluminium-Foil galvanic cell with 1.7 to 1.92 Volts

[stephenafreter]

Found some data about the electrolyte used by this Hong Kong student (see doc linked above)
According to Wikipedia, 1 mol of table salt NaCl is 58.4g
1 mol of sodium hydroxide NaOH is 40g.

2 electrolyte are cited as good ones in the doc, both use 1 mol of salt (58.4g), and one has 0.5 mol (20g) of NaOH page 31, while the other only 0.1 mol of NaOH (4g) page 42. Make your own choice ...

NaOH is widely used as soap/detergent/bleach. Cost is less than 2 USD per kilo in many countries. You can find it in food market for cleaning, textile manufacture for whitening, ... And also in supermarket as drain opener, and for agriculture/gardening purpose.

Sorry if you feel that I hijack the thread, but that data might be useful as reference for new comers, and because I feel this battery concept is worth the investigation.

The main problem is the graphite electrode, as we want large surface area for less material. With good conductivity. The Hong Kong student added some powder to their graphite pencils and got better current output, I wonder what glue they used for such good results ??

[stephenafreter]

A last post for today resuming my last question to go further: What is the right glue to use with the graphite powder, for best conductivity (must also be a none corrosive material)

[hartiberlin]

Hi Stephen and all,
you can use an acryllic binder which is used for painter´s purposes
as the binder.
It has the advantage, that it is waterproof !
So when it has hardened, it is not soluable anymore in water ( electrolyte)

I am using it for my experiments and it is great.

But you can also try out black carbon copy paper.

It is only the surface area of the graphite that counts,
so it does not depend how thick the material is,
so thin sheets of black lampblack imprinted carbon copy
paper should also work great.

Lampblack is one of the best conductive graphite powders.
So use this, it is cheap and can also be got from the painter´s shop.

@Pirate,
yes, Magnesium is the best and powerful
metal for the other electrode, but it is pretty expensive and you can
not get it everywhere, so I prefer to see, how to best build
alufoil-graphite-paper cells with good output power and longer lasting.

As alufoil could be got in every supermarket and it is cheap, it is the ideal
cheap electrode material.

Regards, Stefan.

[hartiberlin]

P.S: I also tried Cement with lampblack and graphite,
but cement as the binder does not work well with the graphite or
lampblack.
It does not get hard very well and when it is
dry again after hardened  the resistance of this cement-graphite electrode is very high and not useable
for batteries.
I also tried to mix in sand, but this does not help to get it hardended and shatterproof.
It crumbles pretty easily, so in my experience it is not usable and the high resistance
is bad.

Regards, Stefan.

[hartiberlin]

Mk1 posted a very interesting document on graphite-alu battery on the "Working Air Battery"
http://www.overunity.com/index.php?action=downloads;sa=view;down=396

Many thanks for this very good document.

It also contains the experiment with a selfbuild Fuel Cell that runs on Alcohol.
They found out that using ethanol alcohol produced the best electrical output.

So that is very interesting.
As ethanol is the drinking alcohol it can be produced very easily in good quantities.
As this one cell produced already 85 Milliwatts this could be probably scaled up
with a bigger surface stack of these cells to a  KiloWatts easily.
The only problem is to find cheaper electrodes for it.

So if you need power, then you go to your supermarket and buy a bottle
of 40 % Vodka or in your pharmacy or drug store and get isopropyl alcohol
and you have power again.
Would be interesting, how long these cells lasts, if you only feed them in ethanol
all the time.
Does one have to refuel also the NaOH again or does this work
more like a catalyst ?