First of all, you're going to have to more rigidly define your terms of durability. Nothing made by the hand of man endures forever, and for that matter, nothing on the surface of the Earth endures perpetually. You didn't claim that your putative battery's case had to survive subduction under the Earth's crust, but you didn't absolutely deny it either.
OK, you're apparently talking about the "memory" or other generalized loss in the ability to hold a charge that occurs in all batteries. Are you acquainted with the cause of this type of wear and tear on various battery types? Does it seem plausible that we can alleviate those causes sufficiently for your problem?