| A Li/oxygen cell which gives a specific energy of more than 700 Wh/kg was developed. The cell consists of a carbon cathode which scavenges oxygen from the atmosphere, a polyolefin separator, a metallic lithium anode, and a lithium salt in an organic electrolyte. It is contained within a plastic packaging material, which doubles as a semi-permeable membrane to oxygen. The effect of cell components such as carbon type and electrolyte type was evaluated. Each carbon type prefers a particular electrolyte. The most important factor was found to be the composition of the electrolyte. Emphasis was put on lowering cell weight, primarily lowering electrolyte amounts (over 50% of the cell weight). The rate capability of the cell was enhanced by the use of catalysts, while membranes allowed for the selective permeation of oxygen while preventing the entry of moisture. It is expected that a careful optimization of cell parameters would lead to specific energies in excess of 1000 Wh/kg. |
