The Aluminum-Air batteries are rechargeable, but they wear out faster than lithium-ion batteries. Eventually, both Aluminum-Air and Lithium-Ion batteries will wear out and need to be replaced, but the Aluminum-Air batteries need to be replaced more often since they wear out faster.

From the ComputerWorld article:

> "The recharge of the aluminum-air [battery] is user-friendly and consists of refilling water and replacing aluminum when depleted," a spokesperson for Alcoa said in an email response to Computerworld. "The water refill is an easy task that can be performed by using tap water on average every one or two months according to mileage driven." The battery's aluminum replacement is also a "quick operation" that will be performed at periodic maintenance checks at a local service station  on average once a year according to mileage driven, the spokesperson added.

According to http://www.computerworld.com/s/article/9248966/Electric_car_..., recharging the battery is "just" replacing the aluminum plates and topping up the water.

And note that there's a classical Li-Ion battery, so the usage scenario seems to be mostly urban users with short commutes (on the Li-Ion, possibly slightly longer on the metal-air battery) with the occasional long trip eating into the metal-air battery.