All-Lithium, Iodide-Based, Low-Melting Electrolytes for High-Temperature Batteries

Abstract

A number of iodide-based electrolytes were prepared and characterized for potential use in high-temperature batteries. These electrolytes contain only Li cations and are candidate replacements for the current all-Li, LiCl-LiBr-LiF minimum-melting electrolyte that is normally used for high-power thermally activated ("thermal") batteries. The main interest in these alternative electrolytes is their lower melting points relative to that of the present all-Li electrolyte that melts at 436degreesC. The larger liquidus range should allow its use to lower operating temperatures, thereby extending the maximum life of the batteries. In this work, the candidate electrolyte were tested with the Li(Si)/FeS2 couple over a range of operating temperatures to bracket typical operating conditions of thermal batteries. One of the compositions tested shows promise for this application.