Well, OK, but gasoline's energy storage includes its own mass, which is combusted to release the energy, whereas the mass of a battery is basically constant despite charging and discharging, so it's not directly comparable in the sense you describe.
However, now that you bring it up, given that the most efficient ICE cars are about 25% efficent, you get at most 3200Wh of actual usable propulsive energy from the kg of gasoline. If the claims pan out, that is within shooting distance of these Li-S batteries' specific energy, even when accounting for EVs' 60-80% battery-to-wheel efficiency.
However, now that you bring it up, given that the most efficient ICE cars are about 25% efficent, you get at most 3200Wh of actual usable propulsive energy from the kg of gasoline. If the claims pan out, that is within shooting distance of these Li-S batteries' specific energy, even when accounting for EVs' 60-80% battery-to-wheel efficiency.