> 400Wh/kg [..] this is nearly double Tesla's energy density Slight quibble: that's specific energy (ie, per mass). Density is per volume. (For airplanes, spec

> 400Wh/kg [..] this is nearly double Tesla's energy density Slight quibble: that's specific energy (ie, per mass). Density is per volume. (For airplanes, specific energy is the hugely important metric)