Advancements in battery technology generally cost an insane amount to advance a teeny bit.
This will be another interesting one for ai.
If ai is worth a hoot-a major advancement in battery technology could be sooner not later.
Battery improvements are measured in improved energy density, longer life, more safety, less environmental impact, and very importantly lower cost to produce. By these measures battery technology is improving at a much lower rate than pretty much any other technology one can think of.