Versatile organic iodide melts and glasses with high mole fractions of LiI: Glass transition temperatures and electrical conductivities

Noting the high σ_o of LiI + LiPS₃ glasses we have explored the properties of salt melts in which all anions are iodide. To obtain these, various low-melting tetraalkylammonium iodides, TAAI's, which may vitrify with up to 70 mo1% LiI, have been synthesized. Some mixtures may remain liquid at room temperature indefinitely. Electrical conductances do not attain the room temperature values of the inorganic LiI glasses though may reach -10^-3 S cm^-1 at 100°C. The organic cations introduce many possibilities for structural manipulation, and may also be polymerized. Preliminary polymerization and conductivity results are reported. The investigation has suggested an important principle (the counter-polarization principle) distinguishing high alkali conductivity in salt or polymer solutions on the one hand and glassy solid electrolytes on the other.