CAPSULE FOR LITHIUM-SULFUR SECONDARY BATTERY, AND LITHIUM-SULFUR SECONDARY BATTERY COMPRISING SAME

A capsule for a lithium-sulfur secondary battery, the capsule comprising a core containing a material capable of forming and restoring a solid electrolyte interface layer and a hydrogel; and a shell formed of a polymer and surrounding the core, is provided. The capsule maintains the solid electrolyte interface layer on a negative electrode for a long time by maintaining the material capable of forming and restoring the solid electrolyte interface layer at a constant level during operation of the lithium-sulfur secondary battery.