The article seems to skirt around this. It gives the energy per weight for just part of the battery and then gives a theoretical energy per volume for the whole

The article seems to skirt around this. It gives the energy per weight for just part of the battery and then gives a theoretical energy per volume for the whole battery. The claimed theoretical improvement for the whole battery per volume is 2x so if the density of the whole battery increases 1.8 to 5x then the solid state battery could be anywhere from slightly better (10%) to significantly worse per weight.