Li-Air Cells with Ensured Safety and Prolonged Shelf-Life Using an Oxygen Selective Membrane Cathode

High performance lightweight energy production and storage technologies are needed to supplement or service as the primary power systems for high altitude airships in order to sustain long-term flight schedules. To address MDA~{!/~}s needs, US Nanocorp proposes to demonstrate the feasibility of fabricating a Li-air battery with a special air electrode for lightweight power source application with ensured safety and prolonged service time. Li-air batteries utilizing a non-aqueous electrolyte are capable of delivering extremely high energy, in excess of 3500 Wh/kg based on the mass of the carbon content of the air electrode. However, safety and cycle-life problems limit the application of the Li-air system. The basic causes of safety and cycle-life problems are from moisture attacking on lithium anode and nonaqueous electrolytes. US Nanocorp~{!/~}s solution to these problems is to use an oxygen selective membrane (~{!0~}OSM~{!1~}) permeable to oxygen but impermeable to moisture in air. This OSM will substitute the air diffusion layer as an oxygen accessing element in an air cathode, being totally resistant to moisture diffusion and allow electrolyte and lithium metal anode to be free of attacking from moisture in air. This Li-air battery system can be further developed into both military and civilian applications.