Provided herein is a lithium-ion battery comprising an electrode assembly, wherein the electrode assembly comprises at least one cathode, at least one anode, and a separator interposed between the at least one cathode and the at least one anode; and wherein the separator comprises a porous base material and a porous polymer layer coated on a surface of the porous base material and adjacent to the at least one cathode. The lithium-ion battery comprising the separator disclosed herein prevents thermal runaway during overcharge, thereby ensuring the safety of lithium-ion battery.