Two electrochemically reversible solid-state batteries using alkali-ion-conducting solid polymer electrolyte (SPE) are to be optimized. For lithium-conducting SPE, a lithium intercalating rutile material (LixWO2) will be used for the negative electrode and titanium disulfide for the positive electrode. In using sodium-conducting SPE, homogeneous matrix electrodes based upon transition metal doped "-alumina will be used for the respective positive and negative elctrodes. Here transition metals will be incorporated into immobile aluminum lattice sites within the "-alumina structure where changes in electrochemical potential upon cell charge/discharge cycling will occur via redox electrochemistry involving these doped immobile transition metal species. Secondary cells possessing these configurations had respective open-circuit potentials of 2.2 and 1.5V, demonstrated good electrochemical reversibility and had theoretical energy dentsities of 175 and 178 Wh/kg. Once the solid-state components are characterized and optimized, they will be incorporated into hermetically sealed prototypes. The anticipated high reliability of these secondary solid-state cells will make them good candidates for such varied applications as utility load leveling, reversible storage devices for electronic and electrochromic displays, in implanted biomedical applications, and reversible power sources in specialized aerospace applications.