Method of preparing lithium secondary battery

A method of preparing a lithium secondary battery, the method comprising:

• preparing a negative electrode by forming a negative electrode active material layer on opposite surfaces of a current collector, the negative electrode having a negative electrode tab;
• preparing a lithium foil having an opening formed at a center thereof and having a closed band shape, in which lithium is coated on one surface or opposite surfaces of a copper foil;
• disposing the negative electrode in the opening of the lithium foil such that the negative electrode does not to overlap the lithium foil except for the negative electrode tab such that the negative electrode tab contacts the lithium foil, and preventing a portion, where the negative electrode tab and the lithium foil are in contact with each other, from being coated with the lithium;
• disposing a separator on at least one surface of a structure formed after disposing the negative electrode in the opening of the lithium foil;
• disposing a positive electrode on the separator to form a stack;
• and
• accommodating the stack in a battery case, and injecting a liquid electrolyte into the battery case to form a solid electrolyte interface (SEI) at initial stage of charging to prevent a reaction of the lithium ions with the negative electrode or other materials during charging and discharging.