4 ms·

one thing I'd have liked that I didn't spot was a joules/kg or joules/volume question, and "size" is a bit nebulous, are they talking volume or energy? if it's

one thing I'd have liked that I didn't spot was a joules/kg or joules/volume question, and "size" is a bit nebulous, are they talking volume or energy? if it's 1/6th cost per volume, but it's 1/7th the energy per volume, lithium would still come out ahead on cost. It's probably not, but the article and the abstract didn't clarify that to my read.

tmikaeld 4y ago
Maybe this is too hard to quantify outside of mass-production? I'd assume that a well-tuned mass-production cycle would drastically reduce size over time, like it did with lithium batteries?
adrian_b 4y ago
For the same energy, the mass of an aluminum electrode would need to be almost 2.4 times greater than the mass of a lithium electrode, in a sulfur-based battery (the ratio can be computed from the enthalpies of the 2 sulfides, the atomic masses of Li and Al, and their number of valence electrons). However, while there are also lithium-sulfur batteries in development, the current lithium-ion rechargeable batteries with Co/Ni/Mn/Fe electrodes have a much worse energy/mass ratio than a lithium-sulfur battery. Moreover, in a lithium-ion battery, the mass of the electrode which stores the lithium is much greater than the mass of the stored lithium (which is intercalated in a porous structure), and the mass of the electrode is only a small fraction of the total mass of the battery. The proposed aluminum-sulfur battery needs good thermal insulation, which will increase the volume in comparison with a lithium battery, but which should not increase much the mass. In conclusion, it is likely that it should be possible to make such a battery at a similar energy per mass with the current Li-ion batteries, but at a worse energy per volume. There is a chance to improve the energy per volume by making a very large battery, which would be possible because there is less risk of fires, but in a large battery the regrowth of the aluminum might be not uniform enough, resulting in a shorter number of charge-discharge cycles until degradation.
- Schroedingersat 4y ago
  You don't have to insulate each module so one would think that last part isn't a consideration

tmikaeld 4y ago

Maybe this is too hard to quantify outside of mass-production? I'd assume that a well-tuned mass-production cycle would drastically reduce size over time, like it did with lithium batteries?

adrian_b 4y ago

For the same energy, the mass of an aluminum electrode would need to be almost 2.4 times greater than the mass of a lithium electrode, in a sulfur-based battery (the ratio can be computed from the enthalpies of the 2 sulfides, the atomic masses of Li and Al, and their number of valence electrons). However, while there are also lithium-sulfur batteries in development, the current lithium-ion rechargeable batteries with Co/Ni/Mn/Fe electrodes have a much worse energy/mass ratio than a lithium-sulfur battery. Moreover, in a lithium-ion battery, the mass of the electrode which stores the lithium is much greater than the mass of the stored lithium (which is intercalated in a porous structure), and the mass of the electrode is only a small fraction of the total mass of the battery. The proposed aluminum-sulfur battery needs good thermal insulation, which will increase the volume in comparison with a lithium battery, but which should not increase much the mass. In conclusion, it is likely that it should be possible to make such a battery at a similar energy per mass with the current Li-ion batteries, but at a worse energy per volume. There is a chance to improve the energy per volume by making a very large battery, which would be possible because there is less risk of fires, but in a large battery the regrowth of the aluminum might be not uniform enough, resulting in a shorter number of charge-discharge cycles until degradation.

Schroedingersat 4y ago
You don't have to insulate each module so one would think that last part isn't a consideration