A lithium secondary battery including a cathode, an anode, and a separation film installed between the cathode and the anode, wherein the cathode includes a cathode active material containing lithium-metal oxide of which at least one of the metals has a continuous concentration gradient region between a core part and a surface part thereof, and the separation film includes a base film, and a ceramic coating layer formed on at least one surface of the base film, such that the lifespan property is significantly improved, while exhibiting excellent penetration safety.