Samsung may have completed work on the graphene battery with which they have been linked over the last few years. This next-gen power-storage technology may improve significantly on its lithium-ion counterpart in some respects. A well-regarded leaker believes that the Note 10 may be in line for these enhancements.
https://www.notebookcheck.net/Samsung-rumored-to-have-completed-graphene-battery-development-may-bring-it-to-Galaxy-Note-10.344811.0.html
Hard to believe that this isn't lithium based but carbon based. A change in electrodes is more likely.
Is it really likely to arrive in 2019? I feel like that's kind of optimistic