Method for preparing core-shell structured particle by using continuous Couette-Taylor crystallizer

1. A method for preparing a core-shell structured particle, the method using a continuous Couette-Taylor crystallizer in which a core reactant inlet, a shell reactant inlet, and a product outlet are sequentially formed on an outer cylinder along a flow direction of a fluid flowing in a Couette-Taylor fluid passage between the outer cylinder and an inner cylinder,

wherein a core particle is primarily formed in the fluid passage by a core reactant supplied through the core reactant inlet; a shell layer is formed on a surface of the core particle to cover the core particle by a shell reactant supplied through the shell reactant inlet; and a core-shell structured particle in which the shell layer is formed on the surface of the core particle to cover the core particle, is discharged to the outside through the product outlet,

wherein each of the core reactant and the shell reactant independently comprises a metallic aqueous solution, a base aqueous solution, and an ammonia aqueous solution,

when at least one of the core reactant or the shell reactant is supplied, gas consisting of nitrogen is continuously supplied to a reactant solution in order to prevent oxidation of the core reactant or the shell reactant, and

wherein a composition of the metallic aqueous solution of the core reactant is different from that of the metallic aqueous solution of the shell reactant, and

wherein a concentration of the shell reactant is 1.0 M or less and wherein a core-shell structured particle consists of a single core particle covered by a shell layer.

2. The method for claim 1 , wherein the core particle comprises a compound of the following Chemical Formula 1, and the shell layer comprises a compound of the following Chemical Formula 2

[Ni x Co y Mn z ](OH) 2   [Chemical Formula 1]

(In the Chemical Formula 1, 0<x<1, 0<y<1, 0<z<1, x+y+z=1, and x>y+z)

[Ni a Co b Mn c ](OH) 2   [Chemical Formula 2]

(In the chemical Formula 2, 0<a<1, 0<b<1, 0<c<1, a+b+c=1, and a=c).

3. The method of claim 2 , wherein the core particle comprises Ni 0.9 Co 0.05 Mn 0.05 (OH 2 ) and the shell layer comprises Ni 0.475 Co 0.05 Mn 0.475 (OH) 2 .

4. The method for claim 1 , wherein a rotational speed of the inner cylinder is in a range of 100 rpm to 3,000 rpm.

5. The method for claim 1 , wherein an average residence time in which the shell reactant remains in the fluid passage until the shell reactant supplied through the shell reactant inlet is discharged to the outside through the product outlet, is in a range of 30 minutes to 90 minutes.

6. The method for claim 1 , wherein a pH of the shell reactant is in a range of 11 to 13.

7. The method for claim 1 , wherein a concentration of the shell reactant is 1.0 M or less; a rotational speed of the inner cylinder is in a range of 100 rpm to 3,000 rpm; an average residence time in which the shell reactant remains in the fluid passage until the shell reactant supplied through the shell reactant inlet is discharged to the outside through the product outlet, is in a range of 30 minutes to 90 minutes; a pH of the shell reactant is in a range of 11 to 13.

8. The method of claim 1 , wherein the ammonia solution is supplied in an amount of 1/10 th of the shell reactant.

9. The method of claim 1 , wherein the core-shell structured particle comprises a nickel-rich core particle.