Trypt_Keeper's recent activity
-
Comment on Tesla announces they're remaining a public company in ~finance
-
Comment on Ten years left to redesign lithium-ion batteries in ~tech
Trypt_Keeper Link ParentIn your example we could use a molar fraction: Li32.4Ni23.9Co9.9Al7.0O26.8 , in which the sum of the subscripts is 100%. Not necessarily :) Your percentages are in terms of moles (number of atoms)...But what if the proportions don't allow this?
In your example we could use a molar fraction:
Li32.4Ni23.9Co9.9Al7.0O26.8
, in which the sum of the subscripts is 100%.Given that we're counting atoms... makes me wonder whether it might not be even more efficient to simply use percentages
Not necessarily :) Your percentages are in terms of moles (number of atoms) yes, but a mole is 6.022x1023 atoms per gram. Mass is measured in grams, not moles.
To help show the difference, let's convert NCA to molar fraction:
Molar Proportion - LiNi0.8Co0.15Al0.05O2
Molar Fraction - Li0.25Ni0.20Co0.0375Al0.0125O0.5A 100kg cathode made with your percentages (so 25kg of Lithium, and so forth) would give us, in molar fraction approx:
Li0.50180Ni0.04748Co0.00887Al0.00645O0.43540
Not exactly the recipe we're after.
Whereas if I knew I wanted to make a cathode of 100kg, I would take the Molar Proportions given in the article, multiply them by each elements Relative Atomic Mass, then take a sum of the mass I have. Then I would make a ratio of the desired Cathode Mass (C) and the sum I just took, and then I would multiply that by each of the numbers I found during the last step. This would give me the mass of each element I would need to combine to make an NCA Cathode. A simple calculator could be written to do this for us, or even an excel sheet (pardon any rounding errors):
Element Atomic Mass Molar Prop. Li 6.94g/mol x 1mol = 6.94g Ni 58.693g/mol x 0.8mol = 46.954g Co 58.933g/mol x 0.15mol = 8.840g Al 26.982g/mol x 0.05mol = 1.349g O 15.999g/mol x 2mol = 31.998g Total: = 96.081
C = 100kg Li C/96.081g x 6.94g = 7.2kg Ni C/96.081g x 46.954g = 48.9kg Co C/96.081g x 8.840g = 9.2kg Al C/96.081g x 1.349g = 1.4kg O C/96.081g x 31.998g = 33.3kg Total = 100kg In chemistry, most everything comes back to everybody's favorite subterranean mammal :)
-
Comment on Ten years left to redesign lithium-ion batteries in ~tech
Trypt_Keeper Link ParentThese subscripts are normalized to molar proportions. If you'll remember back to high school chem, a mole is a measure of approx 6.022x1023 atoms. You will notice that all the subscripts together...These subscripts are normalized to molar proportions. If you'll remember back to high school chem, a mole is a measure of approx 6.022x1023 atoms.
You will notice that all the subscripts together equal an integer, and all the decimals together are equal to 1. The compounds listed in the article are not bonded molecules, but rather metallic-oxide alloys. That is, metals melted and mixed together. In the context of molar proportions, we can simply think of the subscripts as 'parts' in a recipe.For NCA (LiNi0.8Co0.15Al0.05O2) batteries, our cathode is an alloy comprised of Lithium, Nickel, Cobalt, and Aluminum: 1 part Lithium, 0.8 parts Nickel, 0.15 parts Cobalt, 0.05 parts Aluminum, and 2 parts of Oxygen between them all to form the oxides.
If we were to round to whole numbers, we'd get: 20 parts Lithium, 16 parts Nickel, 3 parts Cobalt, 1 part Aluminum, and 40 parts Oxygen — this is a less efficient way to communicate your 'recipe' given that this is more of a mixture, rather than a very large molecule.
The maths to find our quantities of ingredients for a 100kg cathode is far less painful to do with proportions, than it is to use whichever arbitrary numbers we get by rounding your smallest part to 1.
Reading up on that, definitely bizarre. Some stuff about a threesome with a rapper in the allegation as well.
LSD is fun, but it's not much of a sexual drug, and personally I can only barely stand to operate technology at all on any entheogen. Acid does make me quite introspective, so I suppose I can see that as a potential reason for tweeting out his thought like that. But that tweet isn't too out of character for Musk anyway. The man clearly spends most of his time inside his head already. I could see him as the kind of person to use it, but I don't see any reason to think he was necessarily under the influence at the time.