Ension

Lithium-Air battery development – The need for lightweight, high specific energy power sources is apparent for both military and commercial applications. Lithium metal is attractive as a battery anode material because of its lightweight, high voltage, high electrochemical equivalence, and good conductivity. These features have resulted in the use of lithium dominating development of high-performance batteries. The lithium/oxygen cell offers a further size and weight advantage in that the cathode active material (oxygen) is not stored in the cell but is instead supplied from outside air diffusing into the cell as it is needed. It has been demonstrated that in a pure oxygen environment discharge capacity of a prototype organic electrolyte Li/O₂ cell is limited by rate of oxygen transport to the cathode active surface. Construction of a practical battery, however, requires that oxygen be obtained from the atmosphere and dissolved in the electrolyte and that the electrolyte solution remains contained within the battery while this mass exchange takes place. The necessary enabling technology is therefore a membrane with a high permeability to O₂ and a low permeability to organic carbonates. Ension is pursuing an improved oxygen permeable membrane using plasma deposition of polymer films on a microporous substrate material. Plasma enhanced chemical vapor deposition (PECVD) coatings are being applied to the surfaces of microporous membrane materials in order to control the molecular/gas barrier properties of the membranes. Such high-energy batteries have a wide application in many forms of products, ranging from ground and sea vehicles to consumer and medical electronics.