Can rechargable Li-ion batteries be rebuilt?

[Mike94]

After so many cycles, rechargeable Li-ion batteries powering electric cars go bad. This I know.

I am wondering what goes bad? Is it the electrolyte, the electrodes, or both? And in general, could it be possible to take these degraded battery components and fix them?

Thanks in Advance!
Mike

 

[Borek]

No idea what it is that goes bad, but reusing lithium (and some other materials, depending on the battery type) is definitely possible. But it is more like "making a completely new battery" than "fixing the old one".

 

[Roark]

I suppose you can, but I don't think it is worthwhile.

Faradaic reactions are what drives the charge/discharge cycle. When charging, Li+ ions become Lithium metal on the cathode surface. When discharging, Lithium metal releases electrons as it is dissolves into the organic solvent, back to Li+. Then these Li+ ions get into small spaces in the graphene anode. So there are three main components to the battery, right? The anode, the cathode, and the organic solvent. Typically "cycling performance" is associated with the anode or the cathode because they are where most of the problems occur. One way performance can decrease over cycles is when a piece of the cathode or anode breaks off, carrying along with it some lithium on it. This piece is no longer part of the circuit and can't participate in the Faradaic reactions - leading to smaller capacity of the battery. Anodes and cathodes are also the more expensive components, which is why I don't think repairing a battery is an option. You should definitely recycle it though!

[Edit: It is a graphene anode, not graphite.]