Method for manufacturing negative electrode and negative electrode obtained therefrom

1. A method for manufacturing a lithium secondary battery, comprising the steps of:

(S1) forming a preliminary negative electrode by coating a negative electrode slurry comprising a negative electrode active material, conductive material, binder and a solvent onto at least one surface of a current collector, followed by drying and pressing the negative electrode slurry coated current collector, to form a negative electrode active material layer surface on the current collector;

(S2) coating lithium metal foil onto the negative electrode active material layer surface of the preliminary negative electrode in a shape of a pattern in which pattern units are arranged;

(S3) cutting the preliminary negative electrode on which the lithium metal foil is pattern-coated to obtain negative electrode units;

(S4) impregnating the negative electrode units with an electrolyte to obtain a pre-lithiated negative electrode; and

(S5) assembling the negative electrode obtained from step (S4) with a positive electrode and a separator,

wherein step (S3) is carried out by cutting the preliminary negative electrode where each pattern unit is positioned at a central portion of each negative electrode unit and occupies an area equal to or larger than 12% and equal to or smaller than 24% of the negative electrode unit surface, and

wherein a circumference of the pattern unit is spaced apart from a circumference of the negative electrode unit by a predetermined width, and the circumferences do not overlap with each other and do not meet each other.

2. The method for manufacturing the lithium secondary battery according to claim 1 , wherein a ratio of a width of the lithium metal foil pattern unit to a width of a non-coated portion having no lithium metal foil pattern is 99:1 to 10:90, in the negative electrode unit.

3. The method for manufacturing the lithium secondary battery according to claim 1 , wherein a ratio of a length of the lithium metal foil pattern unit to a length of a non-coated portion having no lithium metal foil pattern is 99:1 to 10:90, in the negative electrode unit.

4. The method for manufacturing the lithium secondary battery according to claim 1 , wherein the pattern coating in step (S2) is carried out at a temperature of 10° C. to 200° C. under a linear pressure condition of 0.2 kN/cm to 30 kN/cm.

5. The method for manufacturing the lithium secondary battery according to claim 1 , wherein the impregnation with electrolyte is carried out for 2 hours to 48 hours in step (S4).

6. The method for manufacturing the lithium secondary battery according to claim 1 , wherein after impregnating with an electrolyte in step (S4) and before step (S5), washing and drying the pre-lithiated negative electrode is carried out.

7. The method for manufacturing the lithium secondary battery according to claim 1 , wherein the electrolyte comprises a lithium salt and an organic solvent.

8. The method for manufacturing the lithium secondary battery according to claim 1 , wherein the negative electrode active material layer comprises, as an active material, one or more selected from the group consisting of a Si-based material, Sn-based material, and carbonaceous material.