Allied-Signal has developed batteries which derive their superior performance from the unique combination of properties offered by conductive polymers: electroactivity, mechanical resiliency, and combined ionic and electronic conductivity. Composite electrodes fabricated from conductive polymers and alkali-metal alloys operate with high efficiency and high cycle life. Composite negative electrodes have been combined with cation inserting positive electrodes such as Li xV 6O 13 and Na xCoO 2 to produce high energy density cells having excellent cycle life and a high average voltage, 1.9 V and 2.5 V, respectively. Early Prototype AF-size cells in welded steel cans have demonstrated up to 65 mWh/g (160 mWh/cm 3) and 70 mWh/g (170 mWh/cm 3) for sodium and lithium cells, respectively. Energy densities as high as 100 mWh/g (260 mWh/cm 3) are projected for efficiently packaged sodium cells charged to a higher average voltage (2.8V).