Lithium ion batteries set the standard because they have an acceptable level of all the key metrics: energy storage by weight; energy storage by volume; discharge rate; charging rate; production costs. Every single one of these big breakthrough announcements touts how great this new tech is- in just one or two particular metrics. The problem is that Li-Ion batteries are just barely acceptable in all of those metrics.…
Different battery designs and chemistries are appropriate for different applications. I don't care about how much a battery weighs if it never moves, for example.
On the one hand, you're right that for different applications having different metrics can be acceptable. Sure, a battery for your home that never moves can be heavy and large and that's okay.
But then you have to consider the economics of production. How many of those batteries will you make? What will the factory for them cost to build? And what would it cost instead to just make a bunch more Li-Ion batteries at the existing factory instead?