PROPERTIES AND MORPHOLOGY OF DOPED POLYCRYSTALLINE NA-BETA''-ALUMINA ELECTROLYTES

The effect of trace concentrations of metal oxides, Zn, Mg, Nb and Ge, on the intermediate temperature resistivity of Na-beta''-alumina elec trolytes was investigated. The presence of the dopant oxides resulted in lowered resistivity values over the temperature range of 20 to 350- degrees-C. When the resistivities of the doped electrolytes were norma lized to account for increased grain size relative to undoped samples, it appeared that the most effective additions for improving electroly te conductivity were MgO and Nb2O5. The resistivity of the magnesia-do ped samples at 170-degrees-C was as low as for that of the undoped ele ctrolyte at 290-degrees-C, implying that magnesia doping of lithia-sta bilized beta''-alumina electrolytes may improve the low temperature pe rformance of beta''-alumina-based batteries.