Process for preparing lithium ion cathode material
View Patent ↗There is provided a process for preparing lithium cobaltate and to lithium-containing cobalt oxides which is used in lithium battery cathodes. Also, there is provided cathodes for lithium batteries.
1. A process for preparing lithium metal oxide of the empirical formula:
LiM x K y Co z O 2
Wherein M is an element selected from the group consisting of nickel, manganese, chromium, vanadium and aluminum, wherein
K is an element selected from the group consisting of nickel, vanadium, manganese, aluminum and chromium and is other than M, wherein
x is 0 to 1
y is 0 to 0.8 and
z is >0 to 1, and z+x+y=0.9 to 1.1 consisting of the steps of:
a) mixing the desired stoichiometric amount of cobalt oxide or hydroxide, lithium hydroxide monohydrate and the oxides or hydroxides of a element selected from the group consisting of nickel, manganese, vanadium, aluminum, chromium or a mixture thereof, in the presence of water and low CO 2 atmosphere,
b) heating the mixture of part a) with stirring to about 100 to 250° C. to drive off water; and then
c) heating the material from part b) to about 700 to 950° C. for about 2 to 6 hours.
2. The process of claim 1 including the step of:
a) grinding the material from part c) to a particle size of not more than 100 microns.
3. The process of claim 1 wherein the step of part b) is under vacuum.
4. The process of claim 1 wherein manganese oxide is mixed with lithium hydroxide monohydrate and cobalt hydroxide in part a).
5. The process of claim 1 wherein nickel hydroxide and cobalt hydroxide is mixed with lithium hydroxide monohydrate and LiCO 0.4 Ni 0.6 O 2 is prepared.
6. The process of claim 1 wherein lithium metal oxide is a spinel coated on the surface with cobalt or chromium.
7. The process of claim 5 wherein said lithium metal oxide is LiCO 0.05 Ni 0.95 O 2 .
8. The process of claim 1 wherein M is nickel and K is manganese.
9. The process of claim 1 including a dopant.
10. A process for preparing lithium cobaltate which comprises reacting a compound selected from the group consisting of cobalt oxide and cobalt hydroxide with lithium hydroxide monohydrate in water in low CO 2 atmosphere at a temperature between about 100 to 140° C. to remove water, and then heating between about 700 to 900° C.
11. The process of claim 10 wherein the water is removed under vacuum.
12. The process of claim 11 wherein the vacuum is applied at 100° C.
13. The process of claim 10 wherein a stoichiometric amount of lithium hydroxide monohydrate is used.
14. The process of claim 10 wherein the heating between 200 to 900° C. is for 2.5 to 4 hours.