Aluminum-doped cathode material precursor, and preparation method therefor and use thereof
The present disclosure discloses an aluminum-doped cathode material precursor, and a preparation method therefor and use thereof. The preparation method includes: adding a solution of mixed salts of nickel, cobalt, and calcium, a first aluminum-containing alkali solution, aqueous ammonia, and a sodium hydroxide solution to a medium solution to allow a reaction, and subjecting a resulting reaction product to solid-liquid separation (SLS) to obtain a filter cake; soaking the filter cake in a second aluminum-containing alkali solution, and conducting SLS to obtain a solid material; subjecting the solid material to calcination to obtain a calcined material, and soaking the calcined material in water to obtain the aluminum-doped cathode material precursor. The precursor of the present disclosure realizes the co-precipitation of nickel, cobalt, and aluminum, and by adopting subsequent dechlorination, decalcification, and dehydration, a material with a porous structure is gradually formed which has a low tap density.
1 . A preparation method for an aluminum-doped cathode material precursor, comprising the following steps:
S1: dissolving an aluminum salt in a sodium hydroxide solution to prepare a first aluminum-containing alkali solution;
S2: concurrently feeding a solution of mixed salts of nickel, cobalt, and calcium, the first aluminum-containing alkali solution, aqueous ammonia, and a sodium hydroxide solution into a medium solution to allow a reaction, and controlling a temperature, a pH, and an ammonia concentration of a resulting reaction system; and when a particle size of a reaction product reaches a target value, stopping the feeding, and conducting solid-liquid separation (SLS) to obtain a filter cake;
S3: soaking the filter cake in a second aluminum-containing alkali solution, and conducting SLS to obtain a solid material; and
S4: subjecting the solid material to calcination to obtain a calcined material, soaking the calcined material in water, and conducting SLS to obtain the aluminum-doped cathode material precursor,
wherein the aluminum-doped cathode material precursor has a chemical formula of Ni x Co y Al z O x+y+1.5z , with 0.85≤x≤0.98, 0<y≤0.15, and 0<z≤0.15; the aluminum-doped cathode material precursor is a spherical or spheroidal particle having a porosity of 0.05 cm 3 /g to 0.2 cm 3 /g; and the aluminum-doped cathode material precursor has a particle size D50 of 8.0 μm to 20.0 μm, a specific surface area of 18 m 2 /g to 35 m 2 /g, and a tap density of 1.4 g/cm 3 to 1.8 g/cm 3 .
2 . The preparation method according to claim 1 , wherein in S1, a concentration of sodium hydroxide in the sodium hydroxide solution is 1 mol/L to 2 mol/L, and a molar concentration of Al in the first aluminum-containing alkali solution is 0.1 mol/L to 0.8 mol/L.
3 . The preparation method according to claim 1 , wherein in S2, a molar quantity of calcium ions in the solution of mixed salts is 2±0.1 times a molar quantity of aluminum ions in the aluminum salt.
4 . The preparation method according to claim 1 , wherein in S2, a total molar concentration of nickel, cobalt, and calcium ions in the solution of mixed salts is 1.0 mol/L to 2.5 mol/L.
5 . The preparation method according to claim 1 , wherein the solution of mixed salts is prepared from soluble salts of nickel, cobalt, and calcium, and the soluble salts of nickel, cobalt, and calcium are each at least one of a nitrate or a chloride; and the aluminum salt is at least one of a nitrate or a chloride.
6 . The preparation method according to claim 1 , wherein in S2, the medium solution is a mixed solution of sodium hydroxide and aqueous ammonia, and the medium solution has a pH of 12.0 to 14.0 and an ammonia concentration of 2.0 g/L to 5.0 g/L.
7 . The preparation method according to claim 1 , wherein in S2, the reaction is conducted at a temperature of 45° C. to 65° C., a pH of 10.8 to 11.5, and an ammonia concentration of 2.0 g/L to 5.0 g/L.
8 . The preparation method according to claim 1 , wherein in S3, the soaking is conducted for 1 h to 2 h.
9 . The preparation method according to claim 1 , wherein in S3, a concentration of Al in the second aluminum-containing alkali solution is 0.1 mol/L to 0.8 mol/L.
10 . The preparation method according to claim 1 , wherein in S4, the calcination is conducted at 580° C. to 650° C. for 1 h to 4 h, and a liquid-to-solid ratio of the water to the calcined material is (5,000-15,000) L/t.
11 . The preparation method according to claim 1 , wherein in S4, when the calcined material is soaked in water, ammonium chloride is added to adjust a pH to 6 to 7, and then the calcined material is washed with water.
12 . A preparation method for an aluminum-doped cathode material precursor, comprising the following steps:
S1: dissolving an aluminum salt in a sodium hydroxide solution to prepare a first aluminum-containing alkali solution;
S2: concurrently feeding a solution of mixed salts of nickel, cobalt, and calcium, the first aluminum-containing alkali solution, aqueous ammonia, and a sodium hydroxide solution into a medium solution to allow a reaction, and controlling a temperature, a pH, and an ammonia concentration of a resulting reaction system; and when a particle size of a reaction product reaches a target value, stopping the feeding, and conducting solid-liquid separation (SLS) to obtain a filter cake;
S3: soaking the filter cake in a second aluminum-containing alkali solution, and conducting SLS to obtain a solid material; and
S4: subjecting the solid material to calcination to obtain a calcined material, soaking the calcined material in water, and conducting SLS to obtain the aluminum-doped cathode material precursor,
wherein the aluminum-doped cathode material precursor has a chemical formula of Ni x Co y Al z O x+y+1.5z , with 0.85≤x≤0.98, 0≤y<0.15, and 0<z≤0.15; the aluminum-doped cathode material precursor is a spherical or spheroidal particle having a porosity of 0.05 cm 3 /g to 0.2 cm 3 /g; and the aluminum-doped cathode material precursor has a particle size D50 of 8.0 μm to 20.0 μm, a specific surface area of 18 m 2 /g to 35 m 2 /g, a tap density of 1.4 g/cm 3 to 1.8 g/cm 3 and a degree of sphericity index Φ of the particle is 1.0 to 1.3, wherein Φ=Dc/Di, Di represents a radius of maximum inscribed circle of the particle, and Dc represents a radius of minimum circumscribed circle of the same particle.