Seems to me that if this proves out, and can be made affordably, the most exciting application would be electric cars -- no more range penalty vs. gasoline. Anyone know enough to comment on the likely applicability?
Personally I don't really care too much about charging rates. My battery powered vehicle would be parked overnight. But I do like acceleration. And that's where discharge rates (and other problems) become an issue.
To be honest, I'm too worried about discharge rates, since we use them in combat robots, which are designed to last 3 minutes (which ends up being 20C continuous discharge rate). If you consider that you want at least 2 minutes of "full throttle" power over the course of a charge of the batteries, the capacity of them must be enough that the maximum current would be 30C, otherwise the batteries would be dead from just the hot rodding. Being that you're driving more than the 2 minutes of full throttle, I'd suspect that any batteries with enough capacity for an hour drive would have enough discharge rate to support what you needed to do.
I don't think that people's driving behaviour is divergent enough to support multiple battery chemistries in the long run.
Jay Leno has an antique car that still has a working FeNi battery. I think it needs topped off with distilled water every so often. The electrolyte is KOH so it even acts as a preservative. The only problem with the reaction is it's slow to charge and discharge.
It may have one benefit, but 30 seconds on wikipedia informs me that it requires 5 times the mass and 20 times the volume of lithium ion to give equal energy output. Which makes it a complete non starter for anything mobile.
And also, the fact is that the first cars were electric: they used various chemistries. And as I said above, Leno has a still working car that uses a NiFe battery: Cheap materials, low maintenance, not heavy metal (and nontoxic to boot).
In fact the original recipe indicated making potash, putting it in distilled water, and filtering out the physical chunks of ash.
Even at 220v/30amps it might take a few days,