Abstract: A lithium carbon monoflouride electrochemical cell adapted for high temperature use and storage. The high temperature capability is provided by incorporating into such cells novel components such as a polyetheretherketone grommet, a single layer non-woven glass fiber separator, a sealant which contains up to fifteen percent, by weight, silicone, and an electrolyte which contains an increased proportion of propylene carbonate. For temperatures above 180.degree. C., the metal lithium anode conventionally used in LiCF.sub.x cells may be replaced by a lithium-alloy material.