system
Given the following post, respond as if you're commenting on Reddit:
human
All all rechargeable battery chemistries inherently degrading, or are there technologies either practical or theoretical that would allow for rechargeable batteries that barring mistreatment keep the same capacity?
gpt
There are lots of Electrical energy storages devices that do not degrade with direct usage.  Their issue is that they either are very expensive, or have limited power to weight or volume.

1. Ultra Capacitors.  These can have millions of change/discharge cycles without loss of capacity.  Problem?  Energy Density 
2. Flywheel energy storage.    Used everywhere, ultra robust.  Problem?  Cost and minimum size required.


3. Flow Batteries.  Hydrogen Fuel cells being the most common.   Problems?  Low efficiency, high cost, difficulty in generating clean Hydrogen.


Every electrochemical battery with a self-contained anode, cathode, and electrolyte degrades over time.  The only question there is the number of cycles before they must be recycled.    We can improve the number of cycles, but anything with a redox reaction that doesn't allow us to separate the materials, purge and recycle them, is going to degrade with use.  There are just so many more paths for it to degrade, then there are for it to improve.  Entropy works only in 1 direction.