Researchers from Stanford developed a new cathode material for rechargeable lithium-sulfur batteries - by wrapping sulfur particles in graphene sheets. This new cathode enables batteries with a significantly higher energy density than is currently possible. Such batteries can be used to power electric cars.
Current electric-car batteries 'weak spot' is the cathode materials that have low capacity (about 150 mAh/g for layer oxides and 170 mAh/g for LiFe-PO4). A sulfur cathode has a theoretical specific capacity of 1672 mAh/g - but sulfur is a poor conductor, it expands during discharge, and the polysulfides dissolve in electrolyte. Using graphene to wrap the sulfur may overcome many of these issues.
There are still a lot of performance variability in the current prototypes, and this has to be sorted out before such batteries can be commercialized.
