Elon Musk Announces Tesla's NEW Aluminum-ion Super Battery. 15-min Charging, 5000 Wh/kg Density
Some mad claims are made in that video. One being that the batteries have huge capacity when compared with lithium batteries. Aluminium batteries have half the voltage so you will need twice as many cells.... Doesn't stack up does it, even though a graphene cathode because it is mostly hollow will allow good storage of the aluminium ions.
I made an aluminium ion cell myself in five minutes after seeing this.
I managed to get it to 1.4 volts potential after ten minutes charge on a small lithium charger and its short circuit current was 90 miliamps for as long as I was prepared to torture it. This surprised me for a kitchen top experiment. It does store power and give it out. 90 miliamps into a dead short was a surprise.
Dead easy and fun project I am going to do this summer holiday with my eldest grandson who is 8. He loves stuff like that.
I found some thick braided copper screen from a UHF coax cable and cut off about 60 mm of it. That is the anode for the cell.
I wrapped the anode except the top (my current collector) in paper kitchen towel (my permeable insulation barrier).
I made my cathode out of aluminium kitchen foil, wrapping this around the
insulated copper braid anode, making sure the two electrodes were not shorting anywhere.
The two electrodes fitted nicely into an old plastic solder container - the sort that you get when you buy a small quantity of coiled lead/tin solder.
The electrolyte is just a saturated solution of table salt in water.
I charged the cell up for a few minutes with a small lithium charger running at 4 volts which is a bit much for such a cell, but anyway, after ten minutes, I topped up the electrolyte because some of it had bubbled up as the cell was gassing a bit and it can spilled over the brim.
Aluminium copper sodium cells like this are supposed to top out at about 1.4 volts, which this one shows when it first comes off the charger (1.5v actually), but it settles back down to 1.39 volts.
Aluminium as a cathode is bound to be lower voltage than lithium which has a higher electrical potential because lithium is so much more reactive than aluminium and aluminium has much more tightly bound electrons. Lithium has three electrons and one of them is just dying to get away. That is why lithium is so much in use as a battery material, even with all its disadvantages in cost and reactivity (fire risk). Its willingness to chuck away that outer electron is great for a battery and raises the voltage to 4 volts. Alu batteries have much lower potential - hence my remark about Musk's 'wonder battery' He can not overcome that and will need to run two of his cells in series to match any lithium one.
Quite a fun project for nil outlay and quick to do.
