[user568439]

The non-solid have evolved so much during the last year that now the solid ones are not even better in density. However, I assume the solid state batteries can evolve further since this will just be the first generation.

Normally the promised benefits of solid state batteries were these: - More density - More safety - More cycles - Better in high and low temperatures - Probably cheaper in the long term

At the moment LFP batteries are caching up with a lot of these improvements and the sodium-ion also are starting to improve, reduce price and offer advantages in extreme temperatures. Their density is not good but I think for homes and large storage facilities they can also be a winner if they become very cheap.