lambda -MnO2 demonstrated significantly higher energy density than the conventional heat-treated beta/gamma -MnO2 in primary lithium batteries over the temperature range -40 to +40 degreesC at all discharge rates tested. The largest performance gains were observed for temperatures below 10 degreesC and at discharge rates from 0.1 to 2.0 mA/cm(2). The. improvement in low temperature performance results mainly from the increased voltage and improved discharge kinetics on the 4 V plateau of lambda -MnO2,