Battery with lowest self discharge?

[Grizzman]

Guys who turn a simple hobby into a science degree and go well over the top,we call them anoraks.

Though when you use the term it sometimes doesn't seem to pertain to a person (or their thought processes) at all.

 

[Kestrel]

I'm going to close this thread, as the rather vague and contradictory posts from the OP has provided a rather blank canvas for topic drift.

I'm looking for the battery with the lowest self discharge rate possible.I will take any kind of battery.

Has to be rechargeable, and last for maybe 40 years.

Furthermore, there isn't much of a point to engineering a rechargeable battery with virtually no self-discharge - which has been alluded to by prior poster(s).
(I.e. if it has the ability to be recharged, why engineer in a 40-year LSD property as well?)

The OP is free to open another thread with more specific requirements and considerations.