Process for preparing lithium manganate

1. A process of producing electrode material for the cathode of a lithium battery having the general formula:

Li x Mn y O 4   (I)

Wherein 1≦x≦1.33 and 3−x≦y≦3.1−x and

Li x Mn y M z O 4   (II)

Wherein M is an element selected from the group consisting of Mg, Al, Cr and Ni and

1≦x1.33, 3−x−z≦y≦3.1−x−y and

0<z≦1.0

which comprises the steps of preparing the material of formula (I) by the steps of:

a) mixing stoichiometric amounts of lithium hydroxide monohydrate and a manganese oxide in the presence of water;

b) heating the mixture of step a) at a temperature of about 100 to 180° C. to drive off water to obtain LiMn 2 O 4 .H 2 O;

c) heating the product of step b) to about 650° C. to 900° C. for about 2 to 10 hours, to reduce manganese to Mn+3, and then

d) grinding the product of step c) to less than 100 microns in size, and including in step a) the addition of M oxide wherein M is as herein before described to produce a lithium manganate of formula (II).

2. The process of claim 1 wherein LiMn 2 O 4 is produced by using in step

a) Mn 2 O 3 as the starting material.

3. The process of claim 1 wherein about 0.5 to 5% by weight of chromium oxide is added to step a).

4. The process of claim 1 wherein 0.5 to 5% by weight of the chromium is added as a salt.

5. The process of claim 1 wherein air is utilized to oxidize manganese oxide.

6. The process of claim 1 wherein nickel oxide is added to step a).

7. The process of claim 1 wherein step b) is performed under vacuum.

8. The process of claim 1 wherein step a) is performed under a nitrogen atmosphere.

9. The process of claim 1 wherein manganese oxide in step a) is selected from the group consisting of Mn 2 O 3 , Mn 3 O 4 and MnO.

10. The process of claim 1 wherein step c) is performed by calcining in a furnace under air.

11. The process of claim 1 wherein the product of step d) is ground to about 10 to 20 microns.