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

[broli]

Many thanks for this video.

Are you sure that this decomposed Graphite sheet was then graphene ?

How strong was the H2SO4 acid solution ? What percentage ?

What was used as the other electrode ?

How much graphene to graphite ratio did you get out of the powder when filtrated out ?
How much more conductive is graphene then ?

Many thanks.

Regards, Stefan.

This is not my work but that of a chinese research group doing nano technolgy research. You can find the experiment fully described in their paper here:

http://idv.sinica.edu.tw/lanceli/Paper%20PDF/High-Quality%20Thin%20Graphene%20Films%20from%20Fast%20Electrochemical%20Exfoliation.pdf

But I'll try to answer your questions as well.

Are you sure that this decomposed Graphite sheet was then graphene ?
Yes I'm sure, that's what the research was aimed for.

How strong was the H2SO4 acid solution ? What percentage ?
This is what the paper says: 4.8g of 98% H2SO4 diluted in 100mL of deionized (DI) water

What was used as the other electrode ?
"A Pt wire was chosen as a grounded electrode."

How much graphene to graphite ratio did you get out of the powder when filtrated out ?
I believe most of the electrode that exfoliated are thin graphene sheets.

How much more conductive is graphene then ?
No idea in this case.

[PhiChaser]

@ Stefan: The pultruded carbon tube I have been using for one of the electrodes (the other is aluminum) in my battery experiments has a very low resistance; Between 5-10 ohms per foot (or thereabouts) according to my digital meter. I will have to test with analog meter for better measurements, sorry... It is NOT something you would want to grind up though!! Pretty sure they use a high purity carbon powder and expoxy resins to make the stuff..
Now that I look at my dwindling supply, I think I need to order some more. The last batch I got was from dragonplate.com which has been good to me in the past.

Happy experimenting,
PC

[Cherryman]

Here is some related stuff:


http://physicsworld.com/cws/article/news/48889


http://arxiv.org/abs/1203.0161

[Curious_Celt]

Hi, I'm new to this forum, and have mostly just been reading, and from what I've read so far I am way behind the rest of you guys. But I gotta start somewhere...

As it happens, I made one of these graphite/paper/aluminium foil cells a few nights ago, just to see if I could, and because my brother lives off-grid and wanted me to show him how to make a water/alkali battery, as a back-up to the humungus pile of lead-acid forklift batteries that he currently uses for power.

I have been medically retired for the last 25 years with multiple sclerosis, and my hands don't work so good. However, I succeeded after about three hours, and with a half tea-spoon of caustic soda in a 3/4 pint of water my cell was almost immediately wacking out 1.8VDC at 5.5mA. The cell produced enough energy to light an LED from a defunct solar garden light for about five minutes, which I have to admit, really impressed me, as those LEDs don't even switch on much below 2V.

As a way to while away the time, brilliant. But then later I worked out the cost of making my cell. Came out at £18.59 (including a modest £5/hour labour cost). It would be cheaper for me to go to Morrisons and buy a pack of their AA cells, because I would get six for a quid!

But, at least I now know how to make one if the world ended tomorrow.

On a practical note - has anybody tried using carbon/graphite rods larger than ordinary pencil leads, such as leads from carpenters pencils or carbon arc welding rods, or maybe the recycled carbon rods from dud D cells. The one thing I found with making these really small cells was that the pencil leads are really fragile, and for clumsy sods like me, something thicker would serve two purposes. 1 - the carbon/graphite would not break so easily (which is why it took me three hours), and 2 - the surface area of the carbon/graphite would be greatly increased, thereby giving an increase in current.

I did some measurements and found that for the three pencil leads I used, the total surface area was 33 sq. cm, giving a total electrode area of approximately 66 sq cm. Power density worked at about 0.3 watts per sq cm, which I though was quite good for a rough-made cell. And of course these cells have an advantage over commercial cells. They are recyclable. Just replace the aluminium when it is too corroded, and refresh the electrolyte. Hope I haven't bored too many of you with this...

[neazoi]

Yesterday I tried a battery made out graphite and aluminum with NaOH electrolyte.
I had not seen this thread until today. My experiment was based on the galvanic tables I have seen on the net. I had also the same thoughts as some of the people in this thread, as far as concern the good and bad electrodes, as well as the easiness of finding them.

My goal:
"Making a battery instead of buying one has only sense if it can be made quick, cheap and easily, and this includes the reusability and the cost of parts"

I will post a picture as long as I get back home, but the preliminary results are these:

I used a graphite square rod, taken out of these artists sketch sets, instead of scrapping the fradgile graphite out of a pencil. These sets cost about 2Euros and they contain about 16 rods, of different hardness. The one I have tried marked with an "H". There are others marked with HH, BH etc, which I will try. These represent the hardness of the rod, because sketch artists want rods with different hardnesses. I have not yet measures the resistance of the rod, I will do so.

For the other electrode I used a sheet of aluminum (I thought also that magnesium would be best, but only aluminum is widely available to the consumer). Since aluminum will eventually get consumed, I would like to try cheap aluminum foil as well.

Ok the results. I have tried the battery with a joule thief I have made here http://qrp.gr/energy-harvesting
The LED shines brightly, more brigtly than my previous aluminum/copper/vinegar-salt battery, and it also lasted all night. This morning I slightly tapped my hand on the graphite electrode and then the led continued to lights brightly again. I had not time to watch it more, so I will make some tests today too.