E.g. you change the other part of the battery. "Air breathing" LiO batteries could reach energy densities in the ballpark of other chemical fuels. I think lab d

E.g. you change the other part of the battery. "Air breathing" LiO batteries could reach energy densities in the ballpark of other chemical fuels. I think lab demo cells are around 5MJ/kg nowadays. Traditional chemical fuels have high energy density because we don't include the oxidizer, since it's readily available in the air. Any time you stuff a lot of potential energy into a small space with a low threshold for release you're making something dangerous...