Hi All,
after Lidmotor having success with my idea to use 2 carbon based electrodes for his
Litharge ( lead oxide ) battery,
see:
http://www.youtube.com/watch?v=0g4ZBJ8KFbw&feature=plcpand
http://www.youtube.com/watch?v=jNhMhzMnwT8&feature=plcpI pondered how to come up with a different oxide than lead oxide for
such a cell, cause PbO is so toxic...
Then I remembered hearing about the Aquion cell via Mark Dansie in the Smartscarecrow show recently on Youtube...
and I had another look at:
http://www.aquionenergy.com/blog/bid/108285/What-s-Inside-an-Aqueous-Hybrid-Ion-Batteryand saw that they use MnO2, the material that is also used in Zinc Carbon and Alkali Mangan batteries !
So this Manganese dioxide is a real good replacement for the Lead oxide and it is also cheap
and readily availabe, also from old used up batteries ! You will find it at the used up battery disposals
in every supermarket...
Well. This is how I built the cell:
First I used some carbonfiber thread and a graphite pencil lead to fix the next layer of a carbon fiber sheet to it.
This will be the Minus pole in this cell.
Then I put a layer of toilet paper above it and soaked it from above with a concentrated solution of
NaSO4 in destilled water..
Then I poured on this "NaSO4-wetted" toilet separator a good chunk of wet Manganese Dioxide ( MnO2)
and then layed a layer of stainless stell mesh metal onto it.
The stainless steel layer is then the PLUS pole of this battery.
Now I charged this cell up with my battery charger.. ( My DC power supply is still broken...have to get a new one...)
on the 6 Volts setting...
The cell goes to about 2.7 Volts maximum ( mainly due to supercapaitor- double layer effect) and then comes
down to around 1.6 Volts open circuit voltage.
If you shortcircuit it, it will first deliver shortly over 100 mA going down then to around 10 mA after around
a minute or so ( for a about 5 x 10 cm cell, not so much surface area)..
But I could only light an incandescent 1.2 Volts - 0.22 Amps bulb for just under 1 second...
but I was able to light a yellow LED for a few seconds, which has around 1.65 Volts threshold voltage...
Well I have to build myself a Joule Thief now to see, how long such a cell wuíll power this and will do longer tests
now...
Regards, STefan.
P.S: Enclosed 3 pictures, first showing the open circuit voltage of 1.63 Volts,
next the short circuit current of 11.6 mA after about a minute or so
and the next pic lighting the yellow LED after freshly charged.