Oddly enough, non-rechargeable alkaline batteries already use zinc and manganese (dioxide) (see https://en.wikipedia.org/wiki/Alkaline_battery ).

The article talks about solar energy storage, vehicle batteries, and comparisons with lithium ion. The article doesn't explicitly say they're developing a type of rechargeable battery, but that seems to be implied by context.

Anyway, it would be nice to see lead-acid batteries phased out someday and reduce the usage of lead in human activities.