Electrolyte solution for lithium-sulfur battery and lithium-sulfur battery comprising same

A lithium-sulfur battery comprising:

• a positive electrode and a negative electrode arranged opposite to each other;
• a separator interposed between the positive electrode and the negative electrode;
• and
• an electrolyte solution which is impregnated in the positive electrode, the negative electrode and the separator,
• wherein the electrolyte solution has ion conductivity, and
• wherein the electrolyte solution comprises:
• a lithium polysulfide;
• a non-aqueous solvent consisting of an ether solvent, which is a mixture of a linear ether and a cyclic ether, wherein the cyclic ether comprises at least one selected from the group consisting of dioxolane, methyldioxolane, dimethyldioxolane, vinyldioxolane, methoxydioxolane, ethylmethyldioxolane, dioxane, and trioxane;
• and
• a lithium salt, wherein the lithium salt consists of LiBr,
• wherein the concentration of the lithium salt is in a range of 1M to 4M,
• wherein the electrolyte solution delays passivation by increasing the degree of dissociation of lithium sulfide so as to induce three-dimensional growth of the lithium sulfide on the positive electrode, and
• wherein the electrolyte comprises dissolved lithium polysulfide that is obtained by the reaction of sulfur and lithium sulfide prior to the operation of the battery.