[Gibbon1]

Two thoughts of mine.

A twofold improvement in capacity would kill gasoline cars dead. That's 300 miles of range out of a 600lb battery. Adding up the weights of various components the electric car would weight about the same as a gasoline one.

While the failure modes of metal lithium anode batteries are terrifying that's probably okay for grid applications. Difference between a cell phone stuffed under a pillow and a battery in a concrete vault at at substation.