Solid electrolyte for electrochemical cells and process for making same

摘要

A solid electrolyte for use eg. in gas sensors, leakage indicators, ion-selective electrodes, batteries comprises from 85 to 99.7 mol% of a rare-earth metal fluoride or a mixture of rare-earth metal fluorides and 0.3 to 15 mol. % of an alloying additive; the solid electrolyte having a porous polycrystalline structure with a crystal size of not more than 250 mu m, a pore depth not exceeding the crystal size and a relative density of not less than 0.98. A process for producing the electrolyte comprises mixing the starting components (namely, a rare-earth metal fluoride or a mixture of fluorides of rare-earth metals together with an alloying additive); adding a highly-volatile sintering component to the resulting mixture; by melting the resultant mixture with the removal of the highly-volatile sintering component; cooling the resulting melt to solidification; disintegrating the solidified melt; isolating a fraction with a particle size of not more than 25 mu m and compression moulding the isolated fraction with simultaneous heat-treatment.