Lithium-ion cells have been slowly, steadily improving by a few percent a year for a long time now. A few percent is not a lot, but if these incremental improve

Lithium-ion cells have been slowly, steadily improving by a few percent a year for a long time now. A few percent is not a lot, but if these incremental improvements keep happening then that adds up to some pretty good progress. Cost is also decreasing quite rapidly as economies of scale continue to ramp up. It's not as flashy as some magical new tech that comes along and doubles battery capacities overnight, but on the flip side li-ion is already good enough for most applications. We'll need some pretty big improvements before we can have electric passenger jets, but other than that we're already in pretty good shape.