I can see sodium ion being the right pick for urban ebike rental. It only needs the range to go one way if it's part of a fleet and has the charge infrastructure built out; the rest is a matter of getting enough AV brains in there to minimize issues surrounding safety, parking, self-charging and availability. Once you add that, the bikes become way more appetizing for consumer use and you can expect usage to explode. Several companies are already working on the AV features - and cost is mostly bottlenecked on the batteries.