LITHIUM SECONDARY BATTERY COMPRISING SI-BASED NEGATIVE ELECTRODE ACTIVE MATERIAL

Provided is a lithium secondary battery with reduced Hi-pot defects and improved capacity retention rate. According to one aspect of the present disclosure, there is provided a lithium secondary battery including an anode, a cathode, and a separator interposed between the anode and the cathode, in which the anode includes a Si-based anode active material, the separator includes a separator substrate having a plurality of pores and including a polyolefin resin, the polyolefin resin has a polydispersity index (PDI) of 2.5 to 4.2, an average pore size of 20 to 40 nm, and a maximum pore size of 50 nm or less.