This will have same energy density as TNT. I have a feelings that fully chargred battery of this type might explode
It’s a myth that energy density is a reason to worry about batteries or any other form of energy storage. How much energy is stored doesn’t say anything about how easy it is to release that energy in an uncontrolled way.
For Li-ion batteries it’s not really the electric energy stored you need to worry about at all. It’s the flammable electrolyte.
Solid state batteries are often very safe since they usually don’t have a flammable electrolyte. And when the electrolyte doesn’t burn it’s much harder to get a short and thermal runaway as well