Energy storage devices in many aerospace applications are facing unique challenges. Most of such applications, including remote surveillance, satellites, reusable launch vehicles, etc. depend on high-performance, highly specialized batteries. NASA desires high specific energy batteries that are safe for human exploration missions. Since none exist today, they must be developed. Storagenergy Technologies Inc. and its team members propose to develop a novel core-shell structured sulfur-carbon nanocomposite and novel electrolyte systems for high performance rechargeable lithium-sulfur batteries. In Phase I, the composite materials will be synthesized and characterized. The composite's electrochemical performance along with novel electrolyte systems will be evaluated in full cells. Cells with with a minimum capacity of at least 200 mAh will be fabricated and evaluated. During the Phase II, the composite's composition will be optimized further, its performance in cells with 1Ah will be evaluated, and a low-cost large-scale material production process will be developed.