Cathode slurry composition, cathode for secondary battery and lithium secondary battery
A cathode slurry composition according to an aspect includes a cathode active material, an acrylic dispersant, and a solvent. The cathode slurry composition has a solids content of 65% by weight or more, and a shear viscosity value of 150 Pa·s or less measured at a temperature of 25° C. and a shear rate of 1/s. According to the aspect, a cathode slurry composition having excellent dispersibility, flowability, and the like, as aggregation between active cathode material particles is suppressed, and having a relatively high solids content and low shear viscosity may be provided. According to the cathode slurry composition, a cathode for a secondary battery may be formed having excellent processability without limitations on electrode loading design, coating speed setting, and the like.
1 . A cathode slurry composition comprising:
a cathode active material, an acrylic dispersant, and a solvent,
wherein the acrylic dispersant has a number average molecular weight (Mn) of 10,000 to 50,000,
wherein, in the cathode slurry composition,
a solids content is 65% by weight or more,
a shear viscosity value measured at a temperature of 25° C. and a shear rate of 1/s is 150 Pa·s or less, and
wherein an R PA value according to Equation 1 below is 1.2 or less,
R PA =|( PA 0 −PA 1 )|/ PA 0 [Equation 1]
in Equation 1, R PA is a change rate in a phase angle before and after shearing of a slurry, PA 0 is a phase angle (°) of a slurry before shearing, and PA 1 is a phase angle (°) of a slurry after shearing.
2 . The cathode slurry composition of claim 1 , wherein the acrylic dispersant comprises a polyacrylate-based compound.
3 . The cathode slurry composition of claim 1 , wherein the acrylic dispersant is included in an amount of 0.1 to 10% by weight based on a solids content.
4 . The cathode slurry composition of claim 1 , wherein the cathode active material has an average particle diameter (D50) of less than 5 μm.
5 . The cathode slurry composition of claim 1 , wherein the cathode active material comprises a lithium iron phosphate-based (LFP) active material.
6 . The cathode slurry composition of claim 1 , further comprising:
a conductive material dispersion.
7 . The cathode slurry composition of claim 6 , wherein the conductive material dispersion comprises an additional acrylic dispersant.
8 . A cathode for a secondary battery, wherein the cathode slurry for a secondary battery is formed of the cathode slurry composition according to claim 1 .
9 . The cathode for a secondary battery of claim 8 , wherein an electrode adhesion value is greater than 0.30 N/18 mm.
10 . The cathode for a secondary battery of claim 8 , wherein an electrode resistance value is less than 10.0Ω·cm.
11 . A lithium secondary battery, comprising:
the cathode for a secondary battery according to claim 8 .