spinningmagnets said:
John Goodenough played a part in the early success of Lithium-Ion becoming a viable battery chemistry. Now, he is working on a
glass-based electrolyte to prevent dendrite formation, and the new battery will also be
sodium-based instead of lithium (more available, cheaper) for a type of solid state battery (no liquid electrolyte). Hopefully:
Non-combustable
More energy-dense per volume
Faster charging ability
Higher discharge ability
Longer life, more cycles
http://engr.utexas.edu/news/8203-goodenough-batteries
Although sodium might be more abundant in nature than lithium, I'm really NOT convinced AT ALL that sodium is the best choice to make "better" cells.
The single reason that I can think of is that one mol of sodium is much heavier than one mol of lithium... And heavier is not synonymous with progress IMHO. Remember back in the days when we had eBikes with heavy lead acid batteries ? Well lead is heavy.
To give you numbers, Sodium is 22,9898 g/mol while Lithium 6.983g/mol....
Elementary sodium and elementary lithium are both metals that violently react with almost anything including water (just type "sodium+water" or "lithium+water" in youtube to see some fun explosion). Both these elements have an irrepressible need to ged rid of a single electron so they can become more stable. So sodium or lithium in nature mostly exist as a cathions instead of electroneutral elementary atoms (Na+ instead of Na(0), and Li+ instead of Li(0)).
When looking at the periodic table of elements (https://opentextbc.ca/chemistry/wp-content/uploads/sites/150/2016/05/CNX_Chem_06_04_Ptableconf.jpg)
you can see the electronic configurations of both these elements.
Lithium's electronic configuration is 1s2 2s1 (2 electrons in 1st level s orbital ; 1 electron in 2nd level s orbital.... Total 3 electrons, so there is 3 protons in the nucleus to balance the charge... but also 4 neutrons in the nucleus... So 7 nucleus particules. Hence the weights close to 7g/mol. Eletrons, which are not part of the nucleus, weigh close to nothing in comparison.... Electrons are far from the nucleus. Hence ionisation implies certains amounts of energy... but nuclear fission/fission implies energy amounts far far more vast... but nuclear is not the scope here. electrons are)...
Helium, is a noble gas, which means it is extremly stable and unreactive... Helium's configuration is 1s2... Which means Helium has it's 1st valence orbital layer full, with 2 electrons in the s orbital.
So Lithium's electronic configuration can also be written this way : [He]2s1
Lithium (cat)ion or Li+ has one single electron missing. Why ??? Because when elementary lithium has lost it's electron, it has effectively aquired THE MOST POSSIBLE stable electronic configuration.... That is, Lithium in ion form (Li+) now has the exact same electronic configuration as Helium which is totaly totaly stable (aka totaly inhert or unreactive... the reason it's also called a noble element : it does not react with anything... too stable). This is why metallic lithium (the one kind that's artificially made by chemists, but not found in nature) will spontanously and exothermically react with water or any other kind of oxidizing agent that can oxidize lithium to Li+.
The same logic applies for Sodium (Na). It behave almost completely identically to lithium in électronique terms... It just weights more.
Elementary Sodium's electronic configuration is 1s2 2s2p6 3s1, aka [Ar]3s1 .
1s2 2s2p6 3s1 : 1st valence layer has one s orbital, capable of accepting 2 electrons (one "spin" electron and one "anti-spin" electron). The 2nd valence layer has 4 orbitals, each orbital being capable of holding two electrons : orbital s2, and the three p orbitals (p[x]2, p[y]2, p[z]2) so p6 in short... So the 2nd valence is full at 8 electrons total (2s2p6)... The third valence only has one electrons in the "s" orbital (3s1) and one free space, while the "3p" orbitals are completely emplty (6 free spaces) and the "3d" orbitals too (10 free spaces).
In total, elementary sodium has 11 electrons (2 + 8 + 1), 11 protons in the atom's nucleus to balance that charge and 12 neutrons... So the atom's nucleus has 23 particules (11 + 12) weighting close to 23 g/mol, but also 11 electrons gravitating around that nucleus (electrons weight is relly neglectible)
So by loosing one electron, elementery sodium (Na(0)) becomes cathionic sodium (Na+), thereby adopting the electronic configuration of another Noble element (Argon, another gas) which is also extremely stable.
So think about it for a second. One mol of anything is defining an absolute quantity of something (the avogadro number).... One mol is a quantity of 6.022140857×10^23 particules aka 602 214 087 500 000 000 000 000 paticules... In this very case, we're taking about lithium or sodium cations, which carry the positive charge of the battery.
So in order to have 602 214 087 500 000 000 000 000 positive charges, you would need 22.9898 grams of sodium (1 mole of sodium, because sodium is 22.9898 grams/mol).
To have the exact same 602 214 087 500 000 000 000 000 positive charges with lithium, you only need 6.983 grams of the substance... (1 mole of lithium being 6.983 g/mol).
Yes lithium is getting sort of "rare" to find on this planet, but you need almost 4 times less of it (in terms of weight) to acheive the same thing as you would have to do with sodium. So the concept of "rare" is sort of relative in a way.
I really don't get the hype on Sodium-ion batteries. I have some chemistry backgroung (Master degree in organic synthesis) although the subspecialty of electrochemistry is not my field. Am I missing something here with the sodium ?
I really thought that now that the we had the lithium part working, the next challenge would be to substitute the counter-ions (the anions) to lower weight ones that will still be stable.... Sure some of these single atoms can have multiple negative charges each, but Cobalt, Manganese, Aluminium, etc... these are quite heavy.... What's the next best thing ??
Matador
(No trees were sacrificed in making this post. Probably... Unlike those naughty newsPAPERs. :wink: )
