The structural and electrochemical properties of alpha-MnO2, prepared by acid digestion of Mn2O3, and its lithiated derivatives xLi(2)O . MnO2 (0 less than or equal to x less than or equal to 0.25) have been investigated as insertion compounds in the search for new and viable cathode materials for rechargeable 3 V batteries. The alpha-MnO2 product fabricated by this technique contains water within the large (2 x 2) channels of the structure; the water can be removed from the alpha-MnO2 framework without degradation of the structure, and then at least partially replaced by Li2O (lithium oxide). The Li2O-doped alpha-MnO2 electrodes, described generically as xLi(2)O . MnO2, stabilize the structure and provide higher capacities on cycling than the parent material, The structures of these alpha-MnO2-type electrode materials are described, and electrochemical data are presented for both liquid electrolyte and polymer electrolyte Li/alpha-MnO2 and Li/xLi(2)O . MnO2 cells.