At first I did believe Energizer silver lithiums never leak too, but:
As to the OP, if he is referring to the Duracell nimh cells, I tend NOT to agree they are called Duraloops, for the simple fact from experience that while not one of my almost a hundred Enelooops are still working and nearly at top capacity still, quite a lot of my so-called Duraloops had already lost capacity and some are even disposed of already.