Method of producing negative electrode

A method of producing a negative electrode, comprising:

• providing a negative electrode roll on which a negative electrode structure is wound, the negative electrode structure comprises a negative electrode current collector and a negative electrode active material layer on at least one surface of the negative electrode current collector;
• providing a pre-lithiation bath comprising a pre-lithiation solution, which is sequentially divided into an impregnation section, a pre-lithiation section, and an aging section;
• impregnating the negative electrode structure with the pre-lithiation solution while unwinding the negative electrode structure from the negative electrode roll and moving the negative electrode structure through the impregnation section;
• pre-lithiating the negative electrode structure having passed through the impregnation section while moving the negative electrode structure through the pre-lithiation section;
• and
• aging the negative electrode structure having passed through the pre-lithiation section while moving the negative electrode structure through the aging section,
• wherein the pre-lithiation is performed by disposing a lithium metal counter electrode, which is spaced apart from the negative electrode structure and impregnated with the pre-lithiation solution, in the pre-lithiation section and electrochemically charging the negative electrode structure,
• wherein the electrochemically charging is performed by an oxidation-reduction reaction using an electrochemical charging/discharging device,
• wherein a time for the negative electrode structure to move through the impregnation section is 1 times to 10 times a time for the negative electrode structure to move through the pre-lithiation section,
• wherein a time for the negative electrode structure to move through the aging section is 0.5 times to 21 times a time for the negative electrode structure to move through the pre-lithiation section,
• wherein a ratio of lengths of the impregnation section, the pre-lithiation section, and the aging section ranges from 1 to 10:1:0.5 to 21,
• wherein the negative electrode active material layer comprises a negative electrode active material, and the negative electrode active material comprises a carbon-based active material and a silicon-based active material in a weight ratio of 60:40 to 95:5, and
• the negative electrode structure is moved directly from the impregnation section to the pre-lithiation section in the pre-lithiation solution, and then the negative electrode structure is moved directly from the pre-lithiation section to the aging section in the pre-lithiation solution.