KaiserJeep wrote:Lithium self-discharge is much improved nowadays. I treated myself to a set of DeWalt's "20v MAX" rechargeable Lithium-Ion tools. None of the batteries have been in the charger for 6+ months, but are still charged and the Impact Driver just sank about three dozen 3" deck screws yesterday using a single small 1.5aH battery pack.
Actually it is only a new kind of supercapacitor, even though they claimed that it was an aluminum ion battery. It is the ionic liquid electrolyte (EMImAlCl4) that reacts with (AlCl4- anions intercalate into) graphite foil under moderate voltage, not Al3+ cations from Al electrode. If the Al electrode is replaced by other stable metal or graphite, the results should be the same. Compared with other real aluminum ion battery (Chem. Commun., 2011, 47, 12610–12612), its specific capacity is too low (60 vs 273 mAh/g). As a supercapacitor, its specific capacitance is only 4A/g*54s/(2.45-0.4V)=105.4 F/g. I can only smile on this "Nature" paper.
GHung wrote:2 volts per cell is relatively high.
dissident wrote:They have 2 V already. That nothing to sneeze at by any measure.
KaiserJeep wrote:The main drawback that I see is not low cell voltage,
"Millions of consumers use 1.5-volt AA and AAA batteries," he said. "Our rechargeable aluminum battery generates about two volts of electricity. That's higher than anyone has achieved with aluminum."
But more improvements will be needed to match the voltage of lithium-ion batteries, Dai added.
"Our battery produces about half the voltage of a typical lithium battery," he said
kanon wrote:Here is a comment by "starpigeon" from the phys.org articleActually it is only a new kind of supercapacitor, even though they claimed that it was an aluminum ion battery. It is the ionic liquid electrolyte (EMImAlCl4) that reacts with (AlCl4- anions intercalate into) graphite foil under moderate voltage, not Al3+ cations from Al electrode. If the Al electrode is replaced by other stable metal or graphite, the results should be the same. Compared with other real aluminum ion battery (Chem. Commun., 2011, 47, 12610–12612), its specific capacity is too low (60 vs 273 mAh/g). As a supercapacitor, its specific capacitance is only 4A/g*54s/(2.45-0.4V)=105.4 F/g. I can only smile on this "Nature" paper.
I thought capacitors dissipate the charge rather quickly and, unless i missed it, the time the experimental battery held its charge was not discussed in the article.
In the supercapacitor, energy is stored electrostatically on the surface of the material, and does not involve chemical reactions.
We propose that simplified Al/graphite cell redox reactions during charging and discharging can be written as:
4 Al2Cl7- + 3 e- <=> Al + 7AlCl4- (1)
Cn + AlCl4- <=> Cn[AlCl4] + e- (2)
where n is the molar ratio of carbon atoms to intercalated anions in the graphite. The balanced AlCl4– and Al2Cl7– concentrations in the electrolyte allowed for an optimal charging capacity at the cathode, with abundant AlCl4– for charging/intercalation in graphite (equation (2)), and sufficient Al2Cl7– concentration for charging/electrodeposition at the anode (equation (1)).
pstarr wrote:the story was posted in phy.org.blah. It is the goto site for algae biofuel stories. Enough said.
Peak_Yeast wrote::-s Lets see.. There has been so many promising battery technologies - and none of them became anything.
This invention sounds a little too simple considering how many things that has been tried and discarded. I find it hard to believe that alu and graphite hasnt been tried before. So where is the cat buried?
Peak_Yeast wrote::-s Lets see.. There has been so many promising battery technologies - and none of them became anything.
This invention sounds a little too simple considering how many things that has been tried and discarded. I find it hard to believe that alu and graphite hasnt been tried before. So where is the cat buried?
dolanbaker wrote:Peak_Yeast wrote::-s Lets see.. There has been so many promising battery technologies - and none of them became anything.
This invention sounds a little too simple considering how many things that has been tried and discarded. I find it hard to believe that alu and graphite hasnt been tried before. So where is the cat buried?
I think that the big difference is that the graphite had been "built" using nanotechnology, I don't understand how it actually works, but recent developments in nanotechnology has produced some major leaps in materials technology.
Peak_Yeast wrote::-s Lets see.. There has been so many promising battery technologies - and none of them became anything.
This invention sounds a little too simple considering how many things that has been tried and discarded. I find it hard to believe that alu and graphite hasnt been tried before. So where is the cat buried?
dissident wrote:Peak_Yeast wrote::-s Lets see.. There has been so many promising battery technologies - and none of them became anything.
This invention sounds a little too simple considering how many things that has been tried and discarded. I find it hard to believe that alu and graphite hasnt been tried before. So where is the cat buried?
This plausibility argument doesn't fly. Everything is trivial in hindsight. Going forward not so much.
Your statement is logically equivalent to the claim that all chemical and physical configurations in the Aluminum-Graphite battery field have been tested before or are all similar to each other to the extent that nothing of interest is to be found after doing a few simple attempts.
Users browsing this forum: No registered users and 4 guests