Sodium was making headlines a year ago, as a promising alternative to lithium ion batteries But nowadays all we seem to hear are promises from electric vehicle makers. So where are sodium-ion batteries now, stripped of all the hype … why do we still not find them in our stores?
Why No Sodium-Ion Batteries in Our Cars Either?
Sodium is a promising alternative to lithium, because the material is more abundant. Sodium-based batteries use the same operating principles as lithium versions, so we could use similar production lines too.
However, the deal breaker is the sodium electrolyte, as we know it now. The materials we have just don’t tolerate high voltages, and they perform poorly at low temperatures too. Their electrode – electrolyte interfaces also don’t conduct ions as smoothly as we would like.
What Are Battery Scientists Doing to Fix This?
You may be wondering what are sodium-ion battery scientists doing to fix the electrode – electrolyte interface. Here’s the problem as it stands now:
- The solvent molecules in ion-based batteries reach the metal electrodes ahead of the ions carrying the charge.
- When an ion-based battery starts working, the solvent breaks down and forms a solid-electrolyte interface layer.
- This solid-electrolyte interface (SEI) can become weak, uneven, or unstable, all resulting in poor battery performance.
This is the problem that battery scientists need to fix, before we can look forward to sodium-ion powering our electric cars.
Could Anion-Regulated Electrolytes Fix Sodium-Ion?
Battery scientists are following through on anion-regulated solvents, according to the research report we link to below. These solvents ensure that negative ‘anion’ ions take the lead, in forming protective layers on sodium battery electrodes.
This solution has great potential to improve interface stability between electrodes and electrolytes. This should in turn ensure smoother ion flow leading to greater safety, and tolerance of high and low temperatures.
So yes, now we know where sodium-ion battery chemistry is heading, we have some hope at last. Although we may only see these promising batteries in our stores, in the course of the next few years.
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