Electronic – Why do batteries have a short lifetime despite having no moving parts


Chemical batteries do not seem to have any moving parts, but seem to have a rather short lifetime anyway. Why is this? The only reason I can think of is electrolyte leaking, but I have never noticed a leak of my Li-Ion phone battery and yet I have to replace it at least once a year.

Note, I'm measuring lifetime primarily in cycles of charge/discharge. There are other factors such as temperature and load (or lack thereof for long periods of time).

I'm not only interested in the Li-Ion chemistry. From what I've read, all batteries have a lifetime of charge/discharge cycles, after which they are just no good anymore.

This is apparently one of those rare things that somehow "wears out" quickly despite having no moving parts. The only other thing I know of like that is Flash memory, which wears out because the high voltage needed to write cells degrades them somehow

Best Answer

It is due to the solid state chemistry. In the most simplistic of descriptions, the surfaces of the anode and cathode will have imperfections. Over time, this will result in some of the ion channels becoming restricted as the ions react with the anode/cathode surface, deforming the structure. As the ions cannot move as freely, capacity will suffer.