Redpill me on zinc-air batteries. I keep hearing how it could one day replace lithium-ion batteries. But I don't know if it's all pop-sci bullshit hype or not.

What's the mechanism behind it? Can it work? Is it cheaper? Is it better for the environment? Is it more readily available?

The only thing I know is that it's slightly behind lithium-ion batteries in terms of energy density, but it could improve (?) with more research. Could it one day overtake lithium-ion?