Secondary battery and method for preparing same

A method for preparing a secondary battery, wherein the secondary battery includes a battery cell, the battery cell includes a positive electrode, a negative electrode, a separator and an electrolyte, and the negative electrode includes a negative current collector, and a negative electrode material coating laminated to a surface of the negative current collector, the method comprising:

• preparing a negative electrode slurry, coating the negative electrode slurry on the negative current collector, and then drying and compacting the negative electrode slurry to form the negative electrode material coating, thereby obtaining the negative electrode;
• preparing a positive electrode slurry, coating the positive electrode slurry on a positive electrode collector, and then drying and compacting the positive electrode slurry, thereby obtaining the positive electrode;
• and
• assembling the positive electrode, the negative electrode, the separator and the electrolyte to obtain the secondary battery;
• wherein preparing the negative electrode slurry includes:
• blending a negative electrode active material, a conductive agent, a binder, a dispersant, a solvent, and a thickener to obtain the negative electrode slurry;
• wherein an amount of the negative electrode active material is 96 to 98 parts by weight, an amount of the conductive agent is 0.6 to 1.2 parts by weight, an amount of the binder is 1 to 2.5 parts by weight, an amount of the dispersant is 0.5 to 1.5 parts by weight, an amount of the solvent is 80 to 100 parts by weight, and an amount of the thickener is 1.5 to 3 parts by weight;
• and
• wherein the solvent includes a first solvent and a second solvent, the first solvent is water, the second solvent is an organic solvent, the second solvent has a boiling point of 110° C. to 210° C. and a surface tension of 20 dyn/cm to 50 dyn/cm, and a mass ratio of the second solvent to the first solvent is 1:10 to 1:2.