The present invention relates to a lithium secondary battery and a manufacturing method thereof capable of improving the lifespan properties and high-temperature storage properties of the lithium secondary battery, wherein the lithium secondary battery includes a positive electrode including a positive electrode active material layer containing a positive electrode material and one or more additives selected from succinonitrile (SN), propane sultone (PS), and propene sultone (PRS); a negative electrode; a separator interposed between the positive electrode and the negative electrode; and a gel polymer electrolyte, wherein the additive is included in an amount of 0.2 parts by weight to 5.0 parts by weight based on 100 parts by weight of the positive electrode active material layer.