Based on the Power Energy and Conversion Roadmap TA03 future NASA missions will require high specific energy battery technologies, > 400 Wh/kg. NASA's current missions are using "state-of-the art" (SOA) Li-ion batteries (LIB), which consist of a metal oxide cathode, a graphite anode and an organic electrolyte. The design and chemistry of these cells have a relatively low specific energy (< 200 Wh/kg) and safety issues, therefore they are unable to attain the performance goals indicated in TA03. "Beyond Li-ion" technologies are necessary to make the breakthrough gains in the batteries' specific energy and improved safety. This proposal will address some challenges of the Li-S battery technology, namely (1) low conductivity of the sulfur and (2) volume expansion and (3) the loss of the active material (sulfur) to the "polysulfide shuttle" process resulting in reduced cycle life. The sulfur cathode conductivity needs to be increased because atomic sulfur is an insulator. The sulfur cathode conductivity will be enhanced by using a highly conductive matrix of carbon nanotubes (CNT).