Resistivity measurements of halide-salt/MgO separators for thermal cells

Resistivities of 20 compositions of halide-salt/MgO mixtures (various selections and percentages of LiF, LiCl, LiBr, KCl, KBr, CsBr, and MgO) to be used in Li-alloy/metal sulfide cells have been measured at temperatures between the melting point of a particular mixture and 500°C. The resistivities were determined with cold-pressed electrolyte-binder pellets by using a special cell and DC measuring technique. Temperature, salt composition, and MgO content were found to have a strong influence on resistivity. These factors are listed in decreasing order of the magnitude of the effect. The fabrication density (porosity) of the pellet also has some effect on resistivity. These measured resistivities provide a database to select optimum compositions of electrolyte-binder pellets for LiSi/FeS₂ thermal batteries and to calculate area-specific resistances of these components for battery modeling and optimization