The Effect of MgO‐MgF₂ Synthesis Method on the Electrolyte Binding Ability in Thermal Batteries

Abstract

This paper describes a comparative study of synthesis (sol-gel and suspension methods) of MgF 2 -MgO material used as an immobilizing agent of the electrolyte (KCl-LiCl-RbCl) for high temperature cells. Samples containing 20 mol.% MgF 2 obtained by the sol-gel method, followed by calcination at 500 and 600 o C, were characterized by large specific surface areas greater than those of samples obtained by the suspension method. It was demonstrated that pellets containing 40 wt.% immobilizing agent composed of 20 mol.% MgF 2 -80 mol.% MgO, obtained by the sol-gel method, and calcinated at 500 8C, were good electrolyte immobilizers. This mixture remains dimensionally stable at 400 8C and under 60 kPa pressure (no leakage of the electrolyte was observed) and reveals good ionic conductivity during tests in a model cell -the voltage was not less than 1.0 V and current more than 0.75 A for approximately 400 s.