LiFeS2 Battery with Mixed Salt Electrolyte

Abstract

An nonaqueous electrolyte blend for improved low temperature performance in lithium-iron disulfide cells is contemplated. The electrolyte has at least two solutes, including lithium iodide, wherein the lithium iodide is present at a concentration of 0.26 to 0.45 moles per liter of solvent and wherein the overall concentration of solutes is between 0.40 and 0.75 moles of total solute per liter of solvents. The solvents include DIOX and DME provided at a ratio of DIOX:DME between 50:50 and 70:30, and the solvents must include at least 80 volume percent of ethers.

1 . An FR6 or FR03 battery comprising:
 a spirally wound electrode assembly including an anode consisting essentially of lithium or a lithium alloy and a cathode comprising iron disulfide coated onto a metallic foil; and   an nonaqueous electrolyte consisting essentially of at least two solutes, including lithium iodide, dissolved in a blend of solvents having at least 80 volume percent ethers;   wherein the ethers include 1,3-dioxolane and 1,2-dimethoxyethane provided in a volume ratio of 1,3-dioxolane:1,2-dimethoxyethane between 50:50 and 70:30;   wherein the solutes are provided at 0.40 and 0.75 moles of solutes per liter of solvents; and   wherein the lithium iodide is provided at between 0.26 and 0.45 moles of lithium iodide per liter of solvents.   
     
     
         2 . The battery of  claim 1 , wherein the battery does not experience a sudden voltage dropoff when tested at a temperature of less than −30° C. and at a continuous drain of at least 1.25 A. 
     
     
         3 . The battery of  claim 1 , wherein the solutes consist essentially of lithium iodide and at least one selected from the group consisting of: LiCF 3 SO 3 , LiClO 4 , Li(CF 3 SO 2 ) 2 N, Li(CF 3 CF 2 SO 2 ) 2 N, Li(CF 3 SO 2 ) 3 C and lithium bis(oxalato)borate. 
     
     
         4 . The battery of  claim 1 , wherein the solutes consist essentially of lithium iodide and at least one selected from the group consisting of: LiCF 3 SO 3 , LiClO 4 , Li(CF 3 SO 2 ) 2 N, Li(CF 3 CF 2 SO 2 ) 2 N, LiBF 4 , Li(CF 3 SO 2 ) 3 C, lithium bis(oxalato)borate, lithium bromide, lithium hexafluorophosphate, potassium hexafluorophosphate and lithium hexafluoroarsenate. 
     
     
         5 . The battery of  claim 1 , wherein the solvents consistent essentially of 1,3-dioxolane, 1,2-dimethoxyethane and one or more optional cosolvents. 
     
     
         6 . The battery of  claim 5 , wherein the one or more optional cosolvents is present and selected from the group consisting of: 3,5-dimethylisoxazole, 1,2-dimethoxypropane, 3-methyl-2-oxazolidinone, and beta aminoenones. 
     
     
         7 . The battery of  claim 5 , wherein the one or more optional cosolvents is present and selected from the group consisting of: 1,3-dioxolane based ethers, 1,2-dimethoxyethane-based ethers, ethylene carbonate, propylene carbonate, 1,2-butylene carbonate, 2,3-butylene carbonate, vinylene carbonate, methyl formate, γ-butyrolactone, sulfolane, acetonitrile, N,N-dimethyl formamide, N,N-dimethylacetamide, N,N-dimethylpropyleneurea, 1,1,3,3-tetramethylurea, beta aminoenones, beta aminoketones, methyltetrahydrofurfuryl ether, diethyl ether, tetrahydrofuran, 2-methyl tetrahydrofuran, 2-methoxytetrahydrofuran, 2,5-dimethoxytetrahydrofuran, 3,5-dimethylisoxazole, 1,2-dimethoxypropane, and 1,2-dimethoxypropane-based ethers. 
     
     
         8 . The battery of  claim 1 , wherein the solutes are provided at between 0.40 and 0.65 moles of solutes per liter of solvents.