Lithium Secondary Battery Having Excellent Thermal Safety And Method For Manufacturing The Same

A lithium secondary battery comprising:

• a positive electrode that includes a positive electrode current collector, and a positive electrode active material layer formed on one side or both sides of the positive electrode current collector;
• a negative electrode that includes a negative electrode current collector, and a negative electrode active material layer formed on one side or both sides of the negative electrode current collector;
• and
• a separator that includes a substrate, and an oxide-based solid electrolyte layer that includes lithium aluminum titanium phosphate (LATP) formed on one side or both sides of the substrate,
• wherein the negative electrode active material layer and the oxide-based solid electrolyte layer face each other,
• wherein an inorganic layer that includes a reduced product of the LATP and an SEI material is formed at an interface between the oxide-based solid electrolyte layer and the negative electrode active material layer, and
• wherein an atom content of F in the inorganic layer is from 7 to 15 atomic percent (%) based on all atoms present in the inorganic layer.