Mixed oxide containing a lithium manganese spinel and process for its preparation

1. A process for the preparation of a mixed oxide containing a mixed-doped hyperstoichiometric lithium manganese spinel comprising:

(a) providing components comprising a lithium component, a manganese component, and a boron component, and optionally a component comprising N, wherein N is selected from the group consisting of Al, Mg, Co, Ni, Cu and Cr and optionally a component comprising M, wherein M is selected from the group consisting of Zn, Mg and Cu, wherein at least some of the components are in a dry, powdery form;

(b) preparing a solid mixture by mixing at least some of the dry, powdery components of (a) to form a mixture in dry, powdery form;

(c) preparing a liquid mixture comprising a solvent and a portion of the components of (a) dissolved and/or suspended in the solvent,

(d) mixing the solid mixture of (b) and the liquid mixture of (c) with each other;

(e) drawing the solvent off the mixture obtained in step (d);

(f) calcining the mixture obtained in (e) at a temperature of more than 300° C.;

wherein the stoichiometric quantities of the components of the first and second portions are selected in such a way that a mixed oxide of the following formula results:

[(Li 1−a M a )(Mn 2−c−d Li c N d )O x ]. b (B z O y H u X v )

wherein:

0≦a<0.1;

d<1.2

3.5<x<4.5;

0.01<c<0.06

z=1, 2 or 4

y=1, 2, 3 or 7

u=0, 1, 2 or 3

v=0, 1, 2 or 3

0.01<b<0.5;

M is at least one element from the group of Zn, Mg and Cu;

N is at least one element from the group of Al, Mg, Co, Ni, Cu and Cr; and

X is at least one element from the group Li, Na, K;

whereby a lithium manganese spinel is obtained having a d 50 primary crystallite size of at least 0.5 μm.

2. The process according to claim 1 , wherein the calcining of (f) is carried out in at least two steps, wherein calcination is at temperatures of 300° C. to 600° C. in a first step and at temperatures of 600° C. to 900° C. in a second step.

3. The process according to claim 1 , wherein the D 50 particle size value of the lithium component is less than 30 μm.

4. The process according to claim 3 , wherein before the mixing according to (d) the manganese component has a D 95 particle size value measured by laser granulometry of less than 30 μm.

5. The process according to claim 1 , wherein the solvent of the liquid mixture of (c) is water.

6. The process according to claim 5 , wherein the liquid mixture of (c) contains a portion of the manganese component and/or the component comprising N.

7. The process according to claim 6 , wherein the solid mixture of (b) is stirred into the liquid mixture of (c).

8. The process according to claim 1 , wherein the components of (a) are provided in the form of their nitrates, acetates, oxides, hydroxides and/or carbonates.

9. The process according to claim 4 , wherein the manganese component is selected from the group consisting of manganese carbonate, manganese oxide and manganese dioxide.

10. The process according to claim 1 , wherein the values chosen for b and d are 0.0025<b<0.025 and 0.05<d<0.2.

11. The process according to claim 10 , wherein the values chosen for b, d and a are 0.0025<b<0.025, and 0.08<d<0.15, and 0.005<a<0.02.

12. The process according to claim 11 , wherein N is selected from Al and Mg, and M is Zn.