A Canadian research team has reported a high level of performance in their developmental work related to lithium-sulfur based batteries.  According to the researchers:

This composite material can supply up to nearly 80 percent of the theoretical capacity of sulfur, which is three times the energy density of lithium transition metal oxide cathodes, at reasonable rates with good cycling stability

The team used nanocasting to create the cathode material.  Learn more:  renewableenergyworld.com