Ultralife Batteries delivered the world's first commercial shipments of solid polymer rechargeable batteries in 1997. The battery consists of a LixMn2O4- based cathode, graphite anode and proprietary polymeric separator. Energy density of the batteries exceeds 120 W h kg(-1) and 200 W h dm(-3) at the C rate. Pulse capability up to 5 C has been demonstrated. More than 90% of the initial C rate capacity remains after 500 continuous cycles at room temperature. These solid polymer rechargeable batteries also show good low and high temperature performance and have good safety characteristics.