This article seems a bit off. It says the G-Current battery is fast-charging and will have a range of 3-400 km after ~15 minutes, whereas the Stellary battery charges slower, but that it will have a range of 350 km in 5 minutes and 600 km in 10 minutes. That's faster charging, it just maybe takes longer to get to a certain percentage, but it's clearly a larger capacity battery, so that makes perfect sense.

Terms used in this article are a little different from the usual ones.
But these are solid-state batteries. And those are notoriously expensive to manufacture. No-one has cracked the manufacturing yet.
So these seem to have very good performance but manufacturing and cost might be an issue.