Lithium-sulfur only works hot. It may be a great option for huge batteries connected to the power grid, but plugging a 200°C inflammable battery to your laptop might not increase its safety.
You must be talking about the flow version of lithium-sulfur. The ones with (presumably) graphite and cobalt oxide electrodes are going into e-scooters in China now [0]. However, they are yet far from the theoretical 2x in volumetric density of lithium-ion.
For a very good survey on the state of the art in lithium-sulfur look up this recent study [1].
