Core-shell gradient ternary precursor and preparation method and application thereof

1 . A method of preparing a core-shell gradient ternary precursor, wherein the method comprises the following steps of:

(1) mixing a terephthalic acid solution with alkaline liquor to obtain a terephthalic acid salt solution, adding a nickel source solution for a reaction to obtain a Ni-MOF solution, mixing the Ni-MOF solution with ammonia water, and adjusting pH value to obtain a base solution; and

(2) adding a nickel-cobalt-manganese ternary mixed salt solution, a liquid alkali solution, and an ammonia-water solution simultaneously to the base solution obtained in step (1) for a co-precipitation reaction, and obtaining the core-shell gradient ternary precursor after aging treatment.

2 . The method of claim 1 , wherein:

the terephthalic acid solution in step (1) has a molar concentration of ranging from 1 mol/L to 3 mol/L;

optionally, the alkaline liquor comprises a potassium hydroxide solution;

optionally, the alkaline liquor has a molar concentration of ranging from 2 mol/L to 6 mol/L;

optionally, the terephthalic acid salt solution has a pH value of ranging from 6 to 7;

optionally, the nickel source solution comprises a nickel nitrate solution;

optionally, the nickel nitrate solution has a molar concentration of ranging from 1 mol/L to 3 mol/L; and

optionally, a molar ratio of the terephthalic acid to the nickel element in the nickel source is 1:(0.8-1.2).

3 . The method of claim 1 , wherein;

stirring is performed in a process of the reaction in step (1);

optionally, a stirring time is in a range from 24 h to 48 h;

optionally, filtration, washing, and drying are performed after the reaction;

optionally, a washing agent for the washing comprises anhydrous ethanol; and

optionally, the drying is performed at a temperature of ranging from 40° C. to 60° C.

4 . The method of claim 1 , wherein:

the ammonia water in the base solution in step (1) has a mass concentration of ranging from 4 g/L to 8 g/L;

optionally, Ni-MOF in the base solution has a mass concentration of ranging from 50 g/L to 150 g/L; and

optionally, the base solution has a pH valve of ranging from 11 to 12.

5 . The method of claim 1 , wherein:

a solute in the nickel-cobalt-manganese ternary mixed salt solution in step (2) has a mass concentration of ranging from 80 g/L to 120 g/L;

optionally, the nickel-cobalt-manganese ternary mixed salt solution is added at a rate of ranging from 6 L/h to 10 L/h;

optionally, the liquid alkali solution has a mass concentration of ranging from 28% to 32%;

optionally, the liquid alkali solution is added at a rate of ranging from 2 L/h to 3 L/h;

optionally, the ammonia-water solution has a mass concentration of ranging from 10% to 20%; and

optionally, the ammonia-water solution is added at a rate of ranging from 0.1 L/h to 0.6 L/h.

6 . The method of claim 1 , wherein:

the co-precipitation reaction in step (2) is carried out at a stirring rate of ranging from 200 rpm to 400 rpm;

optionally, the co-precipitation reaction is carried out at a pH value of ranging from 10 to 12;

optionally, the co-precipitation reaction is carried out at a temperature of ranging from 40° C. to 60° C.; and

optionally, a particle size is continuously monitored in the process of the co-precipitation reaction, before the particle size meets the requirements, a high-efficiency thickener is used in the process of the reaction to collect all particles and return them to a reaction kettle for continuous reaction and growth, when the particle size D 50 reaches a range from 3 μm to 4 μm, feeding is stopped, and the reaction is continued until materials react completely.

7 . A core-shell gradient ternary precursor, wherein the core-shell gradient ternary precursor is prepared by the method of claim 1 .

8 . A core-shell gradient ternary positive electrode material, wherein the core-shell gradient ternary positive electrode material is prepared from the core-shell gradient ternary precursor of claim 7 .

9 . A positive electrode plate, comprising the core-shell gradient ternary positive electrode material of claim 8 .

10 . A lithium-ion battery, comprising the positive electrode plate of claim 9 .

11 . The method of claim 2 , wherein:

stirring is performed in a process of the reaction in step (1);

optionally, a stirring time is in a range from 24 h to 48 h;

optionally, filtration, washing, and drying are performed after the reaction;

optionally, a washing agent for the washing comprises anhydrous ethanol; and

optionally, the drying is performed at a temperature of ranging from 40° C. to 60° C.

12 . The method of claim 2 , wherein:

the ammonia water in the base solution in step (1) has a mass concentration of ranging from 4 g/L to 8 g/L;

optionally, Ni-MOF in the base solution has a mass concentration of ranging from 50 g/L to 150 g/L; and

optionally, the base solution has a pH valve of ranging from 11 to 12.

13 . The method of claim 3 , wherein:

the ammonia water in the base solution in step (1) has a mass concentration of ranging from 4 g/L to 8 g/L;

optionally, Ni-MOF in the base solution has a mass concentration of ranging from 50 g/L to 150 g/L; and

optionally, the base solution has a pH valve of ranging from 11 to 12.

14 . The method of claim 2 , wherein:

a solute in the nickel-cobalt-manganese ternary mixed salt solution in step (2) has a mass concentration of ranging from 80 g/L to 120 g/L;

optionally, the nickel-cobalt-manganese ternary mixed salt solution is added at a rate of ranging from 6 L/h to 10 L/h;

optionally, the liquid alkali solution has a mass concentration of ranging from 28% to 32%;

optionally, the liquid alkali solution is added at a rate of ranging from 2 L/h to 3 L/h;

optionally, the ammonia-water solution has a mass concentration of ranging from 10% to 20%; and

optionally, the ammonia-water solution is added at a rate of ranging from 0.1 L/h to 0.6 L/h.

15 . The method of claim 3 , wherein:

a solute in the nickel-cobalt-manganese ternary mixed salt solution in step (2) has a mass concentration of ranging from 80 g/L to 120 g/L;

optionally, the nickel-cobalt-manganese ternary mixed salt solution is added at a rate of ranging from 6 L/h to 10 L/h;

optionally, the liquid alkali solution has a mass concentration of ranging from 28% to 32%;

optionally, the liquid alkali solution is added at a rate of ranging from 2 L/h to 3 L/h;

optionally, the ammonia-water solution has a mass concentration of ranging from 10% to 20%; and

optionally, the ammonia-water solution is added at a rate of ranging from 0.1 L/h to 0.6 L/h.

16 . The method of claim 4 , wherein a:

solute in the nickel-cobalt-manganese ternary mixed salt solution in step (2) has a mass concentration of ranging from 80 g/L to 120 g/L;

optionally, the nickel-cobalt-manganese ternary mixed salt solution is added at a rate of ranging from 6 L/h to 10 L/h;

optionally, the liquid alkali solution has a mass concentration of ranging from 28% to 32%;

optionally, the liquid alkali solution is added at a rate of ranging from 2 L/h to 3 L/h;

optionally, the ammonia-water solution has a mass concentration of ranging from 10% to 20%; and

optionally, the ammonia-water solution is added at a rate of ranging from 0.1 L/h to 0.6 L/h.

17 . The method of claim 2 , wherein:

the co-precipitation reaction in step (2) is carried out at a stirring rate of ranging from 200 rpm to 400 rpm;

optionally, the co-precipitation reaction is carried out at a pH value of ranging from 10 to 12;

optionally, the co-precipitation reaction is carried out at a temperature of ranging from 40° C. to 60° C.; and

optionally, a particle size is continuously monitored in the process of the co-precipitation reaction, before the particle size meets the requirements, a high-efficiency thickener is used in the process of the reaction to collect all particles and return them to a reaction kettle for continuous reaction and growth, when the particle size D 50 reaches a range from 3 μm to 4 μm, feeding is stopped, and the reaction is continued until materials react completely.

18 . The method of claim 3 , wherein:

the co-precipitation reaction in step (2) is carried out at a stirring rate of ranging from 200 rpm to 400 rpm;

optionally, the co-precipitation reaction is carried out at a pH value of ranging from 10 to 12;

optionally, the co-precipitation reaction is carried out at a temperature of ranging from 40° C. to 60° C.; and

optionally, a particle size is continuously monitored in the process of the co-precipitation reaction, before the particle size meets the requirements, a high-efficiency thickener is used in the process of the reaction to collect all particles and return them to a reaction kettle for continuous reaction and growth, when the particle size D 50 reaches a range from 3 μm to 4 μm, feeding is stopped, and the reaction is continued until materials react completely.

19 . The method of claim 4 , wherein:

the co-precipitation reaction in step (2) is carried out at a stirring rate of ranging from 200 rpm to 400 rpm;

optionally, the co-precipitation reaction is carried out at a pH value of ranging from 10 to 12;

optionally, the co-precipitation reaction is carried out at a temperature of ranging from 40° C. to 60° C.; and

optionally, a particle size is continuously monitored in the process of the co-precipitation reaction, before the particle size meets the requirements, a high-efficiency thickener is used in the process of the reaction to collect all particles and return them to a reaction kettle for continuous reaction and growth, when the particle size D 50 reaches a range from 3 μm to 4 μm, feeding is stopped, and the reaction is continued until materials react completely.

20 . The method of claim 5 , wherein:

the co-precipitation reaction in step (2) is carried out at a stirring rate of ranging from 200 rpm to 400 rpm;

optionally, the co-precipitation reaction is carried out at a pH value of ranging from 10 to 12;

optionally, the co-precipitation reaction is carried out at a temperature of ranging from 40° C. to 60° C.; and

optionally, a particle size is continuously monitored in the process of the co-precipitation reaction, before the particle size meets the requirements, a high-efficiency thickener is used in the process of the reaction to collect all particles and return them to a reaction kettle for continuous reaction and growth, when the particle size D 50 reaches a range from 3 μm to 4 μm, feeding is stopped, and the reaction is continued until materials react completely.