Salt additives for secondary sulfur batteries

A method of improving performance of a lithium-sulfur battery, comprising a sulfur-containing cathode, a lithium-containing anode, and an electrolyte ionically coupling the lithium-containing anode and the sulfur-containing cathode, wherein one or more salt additives comprising a metal di-cation is added to the electrolyte, wherein the metal di-cation is zinc, and wherein the secondary lithium-sulfur battery has an electrolyte-to-sulfur ratio equal to or less than 3.5 microliters of electrolyte per milligram of electroactive sulfur, and wherein each of the one or more salt additives is selected from the group consisting of zinc nitrate, zinc trifluoromethanesulfonate, zinc di[bis(trifluoromethylsulfonyl)imide], zinc trifluoroacetate hydrate, zinc acrylate, zinc methylacrylate, zinc dimethyldithiocarbamate, and combinations thereof.

In a secondary lithium-sulfur battery having a sulfur-containing cathode, a lithium-containing anode, and an electrolyte ionically coupling the lithium-containing anode and the sulfur-containing cathode, the improvement comprising adding one or more salt additives comprising a metal di-cation, wherein the metal di-cation is zinc, and wherein the secondary lithium-sulfur battery has an electrolyte-to-sulfur ratio equal to or less than 3.5 microliters of electrolyte per milligram of electroactive sulfur and wherein each of the one or more the salt additives is selected from a group consisting of zinc nitrate, zinc trifluoromethanesulfonate, zinc di[bis(trifluoromethylsulfonyl)imide], zinc trifluoroacetate hydrate, zinc acrylate, zinc methylacrylate, zinc dimethyldithiocarbamate, and combinations thereof.