Methods of making inorganic compounds
The invention relates to a chemical compound of the formula Ni b M1 c M2 d (O) x (OH) y , wherein M1 denotes at least one element from the group consisting of Fe, Co, Mg, Zn, Cu and/or mixtures thereof, M2 denotes at least one element from the group consisting of Mn, Al, B, Ca, Cr and/or mixtures thereof, wherein b≤0.8, c≤0.5, d≤0.5, and x is a number between 0.1 and 0.8, y is a number between 1.2 and 1.9, and x+y=2. A process for the preparation thereof, and the use thereof as a precursor for the preparation of cathode material for secondary lithium batteries are described.
1. A method of making a powder comprising a partly oxidized mixed metal hydroxide as a precursor for the preparation of cathode material for lithium secondary batteries,
the partly oxidized mixed metal hydroxide being a homogeneous product represented by the formula
Ni b M1 c M2 d (O) x (OH) y
wherein
M1 denotes only one element selected from the group consisting of Co and Mg,
M2 denotes only one element selected from the group consisting of Mn, B, and Cr,
b≤0.65
c≤0.5
d≤0.5, and
x is a number between 0.1 and 0.54,
y is a number between 1.46 and 1.9, and x+y=2,
which has an average degree of oxidation of 2.1 to 2.54, and
wherein the partly oxidized mixed metal hydroxide further contains sodium, and a content of sodium in the partly oxidized mixed metal hydroxide is less than 2,000 ppm, and
wherein the powder has a standardized width of a particle size distribution, defined according to formula (1), is less than 1.8
( D 90− D 10)/ D 50 (1),
wherein D denotes a diameter of the powder particles, and
wherein the powder has an average particle size, measured in accordance with ASTM B 822, of 2-30 μm
the method comprising the following steps:
a. co-precipitating spherical mixed metal hydroxides from corresponding metal salt solutions,
b. separating off the co-precipitated mixed metal hydroxide from the suspension,
c. washing the mixed metal hydroxide,
d. drying and simultaneously partially oxidizing the mixed metal hydroxide under an oxygen-containing atmosphere at a temperature of greater than 80° C. for at least 3 hours.
2. The method according to claim 1 further comprising partially oxidizing the co-precipitated mixed metal hydroxides using an oxidizing agent before separating off the co-precipitated partly oxidized mixed metal hydroxide from the suspension.
3. The method according to claim 1 , wherein the powder comprising the mixed metal hydroxide contains no gamma-oxyhydroxide structures.
4. The method according to claim 1 , wherein the powder comprising the mixed metal hydroxide contains no alpha-hydroxide structures.
5. The method according to claim 1 , wherein the content of sodium in the partly oxidized mixed metal hydroxide is less than 1,000 ppm.
6. The method according to claim 1 , having a tap density, measured in accordance with ASTM B 527, of greater than 1.7 g/cm 3 .
7. The method according to claim 1 , wherein the powder comprising the mixed metal hydroxide has a tap density, measured in accordance with ASTM B 527, of greater than 1.9 g/cm 3 .
8. The method according to claim 1 , wherein the powder comprising the mixed metal hydroxide has an average particle size, measured in accordance with ASTM B 822, of 3-15 μm.
9. The method according to claim 1 , wherein the powder comprising the mixed metal hydroxide comprise spherical particles.
10. The method according to claim 1 , wherein the powder comprising the mixed metal hydroxide comprise particles having a shape factor of greater than 0.7.
11. The method according to claim 1 , wherein the powder comprising the mixed metal hydroxide comprise particles having a shape factor of greater than 0.9.
12. The method according to claim 1 , wherein the standardized width of the particle size distribution, defined according to formula (1), is less than 1.2
( D 90− D 10)/ D 50 (1),
wherein D denotes the diameter of the powder particles.
13. The method according to claim 1 , wherein M1 is Co and M2 is Mn.
14. The method according to claim 1 , wherein the metal salt is a sulfate and the co-precipitation is conducted by addition of alkalihydroxide solution.
15. The method according to claim 1 , wherein step d comprises drying and simultaneously partially oxidizing the mixed metal hydroxide under an oxygen-containing atmosphere at a temperature of greater than 80° C. for 3 to 24 hours.