You may be leaping to conclusions here about the energy density. I have seen no info that says the battery is 2.5 times heavier for a given energy capacity. The article from UT only said that the volumetric energy was higher. There is no information about the specific energy (wh/kg). Throughout the rest of the article they only refer to energy density without specifying Wh/liter or Wh/kg. I think it is a huge leap to deduce that this technology will be 2.5 times heavier for a given energy density.That does not make sense. A glass electrolyte will be very thin and is not likely to add much weight to the battery. The weight is much more likely to be dependent on the electrode materials and the weight of any necessary containment materials. Some battery chemistries require steel plates compressing every cell to prevent electrode expansion.