Fabrication method of positive electrode for secondary battery and secondary battery including the positive electrode
The present invention provides a fabrication method of a positive electrode for a secondary battery, including: (a) heating a slurry composition for a positive electrode containing a positive electrode active material, a binder, and a solvent to a temperature lower than a boiling point (T b ) of the solvent; (b) applying the heated slurry composition for a positive electrode onto a current collector; and (c) cooling the applied slurry composition for a positive electrode.
1. A fabrication method of a positive electrode for a secondary battery, comprising:
(a) heating a slurry composition containing a positive electrode active material, a binder, and a solvent to a temperature lower than a boiling point (T b ) of the solvent;
(b) applying the heated slurry composition onto a current collector;
(c) cooling the applied slurry composition; and
(d) drying the cooled slurry composition,
wherein the cooling is performed immediately after the applying and at a temperature of 10 to 30° C., and
wherein the drying is performed at a temperature of 100° C. or more and less than 180° C.
2. The fabrication method of a positive electrode for a secondary battery of claim 1 , wherein a solid in the slurry composition for a positive electrode is contained in an amount of more than 74 parts by weight and 90 parts by weight or less based on 100 parts by weight of the slurry composition for a positive electrode.
3. The fabrication method of a positive electrode for a secondary battery of claim 1 , wherein a viscosity (A 1 ) of the slurry composition for a positive electrode before being heated is 13,000 to 80,000 cP.
4. The fabrication method of a positive electrode for a secondary battery of claim 1 , wherein a temperature (T) of the heating of the slurry composition for a positive electrode satisfies the following Relational Equation 1:
0.3 T b <T< 0.9 T b [Relational Equation 1]
wherein T b is the boiling point of the solvent.
5. The fabrication method of a positive electrode for a secondary battery of claim 1 , wherein the cooling is performed for 1 to 60 seconds.
6. The fabrication method of a positive electrode for a secondary battery of claim 1 , wherein the slurry composition for a positive electrode satisfies the following Relational Equations 2 and 3:
1.3≤ A 1 /A 2 ≤12 [Relational Equation 2]
1.1≤ A 3 /A 2 ≤10 [Relational Equation 3]
wherein A 1 is a viscosity of the slurry composition before being heated, A 2 is a viscosity of the heated slurry composition for a positive electrode, and A 3 is a viscosity of the cooled slurry composition for a positive electrode.
7. The fabrication method of a positive electrode for a secondary battery of claim 1 , wherein the drying is performed at a temperature of 110° C. or more and less than 145° C. for 20 to 150 seconds.