The best foreseen improvement, which is only in the R & D stages at present, is for a 10-fold increase over lithium-ion.
IMO, this is no more than a
PR stunt to perhaps claim a 1st in electric flight. Should this be Sikorsky's intent, they may wish to read page 3 of this
article on the Hummingbird. It has been stated by a separate source that it did leave the ground.
Dave