Methods for preparing particle precursor, and particle precursor prepared thereby

1. A method for preparing a core-shell structured particle precursor, comprising the following steps:

from an initial time t 0 to a first time t 1 , feeding a first anion composition B 1 through a first container into a reactor, and feeding a first cation composition A 1 through a second container into the reactor, the first anion composition B 1 and the first cation composition A 1 reacting and precipitating in the reactor, t 1 comes after to, t 0 =0;

at the first time t 1 , the first container is full of the first anion composition B 1 , and the second container is full of the first cation composition A 1 ;

feeding a second anion composition B 2 through a third container into the first container and feeding the second anion composition B 2 and the first anion composition B 1 through the first container into the reactor from the first time t 1 to a second time t 2 , t 2 comes after t 1 , during which the first anion composition B 1 is gradually switched to the second anion composition B 2 wherein the first anion composition B 1 is hydroxide salts, and the second anion composition B 2 is at leaset one selected from the group consisting of carbonate, oxalate, or a comination thereof; and feeding at least the first cation composition A 1 through the second container into the reactor from the first time t 1 to the second time t 2 , thereby forming a precipitated particle slurry; and

filtering, and drying the precipitated particle slurry to yield the particle precursor;

wherein instantaneous concentration of anions being fed into the reactor from the first time t 1 to the second time t 2 can be described as:

B

=

B

i

⁢

V

i

+

(

F

B

⁢

2

⁢

B

⁢

2

-

B

i

⁢

F

B

)

⁢

(

t

i

+

1

-

t

i

)

V

i

+

1

,

wherein:

B is the instantaneous concentration of anions being fed into the reactor;

B i is the anion concentration at time t i that exists in the first container;

V i is the volume of solution at time t i that exists in the first container;

F B2 is the flowrate from the third container into the first container;

B2 is the anion concentration in the third container;

F B is the flowrate from the first container into the reactor;

t i+1 is time at moment i+1;

t i is time at moment i;

V i+1 is the volume of solution at time t i+1 that exists in the first container.

2. The method of claim 1 , wherein the first anion composition B1 and/or the second anion composition B 2 has a concentration 0.001-14 mol anion/L; and/or the first cation composition A 1 has a concentration 0.001-6 mol cation/L.

3. The method of claim 1 , wherein the first anion composition B1 and/or the second anion composition B2 is at least one selected from the group consisting of NaOH, Na 2 CO 3 , NaHCO 3 , Na 2 C 2 O 4 , LiOH, Li 2 CO 3 , LiHCO 3 , Li 2 C 2 O 4 , KOH, K 2 CO 3 , KHCO 3 , K 2 C 2 O 4 , or combination of the species; and/or

the first cation composition A 1 is at least one selected from the group consisting of Mg, Ca, Zr, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Al, in a form of sulfate, carbonate, chloride, nitrate, fluoride, oxide, hydroxide, oxyhydroxide, oxalate, carboxylate, acetate, phosphate or borate.

4. The method of claim 1 , wherein method further comprises the following step:

feeding the second anion composition B 2 and the first cation composition A 1 into the reactor from the second time t 2 to a third time t 3 , t 3 comes after t 2 .

5. The method of claim 1 , wherein during the initial time t 0 to the second time t 2 , the first cation composition A 1 is the only cation that is fed into the reactor.

6. The method of claim 1 , wherein from the initial time t 0 to the first time t 1 , the first cation composition A 1 is fed through the second container into the reactor; and

feeding a second cation composition A 2 through a fourth container into the second container and feeding the second cation composition A 2 and the first cation composition A 1 through the second container into the reactor from the first time t 1 to the second time t 2 , during which the first cation composition A 1 is gradually switched to the second cation composition A 2 .

7. The method of claim 1 , wherein from the initial time t 0 to a switching time t s , the first cation composition A 1 is fed through the second container into the reactor, t s is between the first time t 1 and the second time t 2 ; and

from the switching time t s to the second time t 2 , feeding a second cation composition A 2 and the first cation composition A 1 through the second container into the reactor, during which the first cation composition A 1 is gradually switched to the second cation composition A 2 .

8. The method of claim 1 , wherein the first cation composition A 1 and the second cation composition A 2 has a cation ratio of Ni x Mn y Co z Me 1-x-y-z , where x+y+z≤0.9, z≤0.2, “Me” is at least one additional metal elements selected from the group consisting of Mg, Ca, Zr, Ti, V, Cr, Fe, Cu and Al.

9. The method of claim 1 , wherein a pH during the reaction is 7-13 which is gradually changed, the pH is 9.5-12.5 when precipitating hydroxides, the pH is 7-10 when precipitating carbonates; and/or a temperature during the reaction is 30-80° C.

10. The method of claim 1 , wherein the step that the first anion composition B 1 is gradually switched to the second anion composition B 2 comprises the following steps:

at the first time t 1 , the first container is full of the first anion composition B 1 ;

gradually feeding the second anion composition B 2 from the third container into the first container from the first time t 1 to the second time t 2 , such that the first anion composition B 1 and the second anion composition B 2 form a dynamic mixture in the first container;

feeding the dynamic mixture through the first container into the reactor from the first time t 1 to the second time t 2 ;

at the second time t 2 , the first container is mainly full of the second anion composition B 2 .

11. The method of claim 6 , wherein the step that the first cation composition Ai is gradually switched to the second cation composition A 2 comprises the following steps:

at the first time t 1 , the second container is full of the first cation composition A 1 i;

gradually feeding the second cation composition A 2 from the fourth container into the second container from the first time t 1 to the second time t 2 , such that the first cation composition A 1 and the second cation composition A 2 form a dynamic mixture in the second container;

feeding the dynamic mixture through the second container into the reactor from the first time t 1 to the second time t 2 ;

at the second time t 2 , the second container is mainly full of the second cation composition A 2 .

12. The method of claim 7 , wherein the step that the first cation composition Ai is gradually switched to the second cation composition A 2 comprises the following steps:

at the switching time t s , the second container is full of the first cation composition A 1 ;

gradually feeding the second cation composition A 2 from the fourth container into the second container from the switching time t s to the second time t 2 , such that the first cation composition A 1 and the second cation composition A 2 form a dynamic mixture in the second container;

feeding the dynamic mixture through the second container into the reactor from the switching time t s to the second time t 2 ;

at the second time t 2 , the second container is mainly full of the second cation composition A 2 .

13. The method of claim 8 , wherein the first cation composition A 1 has a cation ratio of Ni x Mn y Co z Me 1-x-y-z , where x+y+z≥0.9, 0.75≤x≤1; 0≤0.1;; and/or the second cation composition A2 has a cation ratio of Ni x Mn y Co z Me 1-x-y-z , where x+y+z≥0.9, 0.3≤x≤0.7; 0.25≤y≤0.5, “Me” is at least one additional metal elements selected from the group consisting of Mg, Ca, Zr, Ti, V, Cr, Fe, Cu and Al.