Lithium manganese oxide compositions
The present disclosure relates to improved LMO composition suitable for use as cathode material in rechargeable lithium ion batteries. The LMO composition may be doped with an additional metal or undoped. The LMO composition carries a surface treatment of LiF that protects the LMO from acid degradation. Cathodes prepared from the improved LMO have improved fade characteristics.
1. A method for preparing cathode active material comprising:
selecting a cathode active starting material from the group consisting of Li 1+x M y Mn 2−x−y O 4 where 0<x<0.25, 0<y<0.5 and M is one or more trivalent metals from the group Al, Cr, Ga, In and Sc and Li[Li( 1-2x ) /3 M y Mn( 2−x ) /3 Ni x.y ]0 2 where 0<x<0.5, 0<y<0.25, x>y and M is one or more metals chosen from Ca, Cu, Mg and Zn;
dry blending LiF particles with the selected starting material, wherein the resulting dry blend comprises from 0.25 to 2.5% by weight LiF;
heating the resulting dry blend at a temperature between about 700° C. and 850° C. for a period of about two hours to about six hours to activate the LiF and to provide a final composition in the form of a cathode active material carrying a surface treatment of LiF on the surface of the cathode active material, said surface treatment of LiF in direct contact with said cathode active material.
2. A method for preparing cathode active material comprising:
selecting a starting material from the group consisting of Li 1+x M y Mn 2−x−y O 4 where 0<x<0.25, 0<y<0.5 and M is one or more trivalent metals from the group Al, Cr, Ga, In and Sc and Li[Li( 1−2x ) /3 M y Mn (2−x)/3 Ni x.y ]0 2 where 0<x<0.5, 0<y<0.25, x>y and M is one or more metals chosen from Ca, Cu, Mg and Zn;
dry blending LiF particles with the selected starting material, wherein the resulting dry blend comprises from 0.25 to 2.5% by weight LiF;
heating the resulting dry blend at a temperature between about 700° C. and 850° C. for a period of about two hours to about six hours to provide a final composition in the form of a cathode active material carrying a surface treatment of LiF on the surface of the cathode active material, said surface treatment of LiF in direct contact with said cathode active material.
3. A method for preparing a cathode material comprising:
selecting a starting material from the group consisting of a cathode active material having the general formula of Li 1+x M y Mn 2−x−y O 4 where 0<x<0.25, 0<y<0.5 and M is one or more trivalent metals from the group Al, Cr, Ga, In and Sc or Li[Li( 1−2x ) /3 M y Mn (2−x)/3 Ni x.y ]0 2 where 0<x<0.5, 0<y<0.25, x>y and M is one or more metals chosen from Ca, Cu, Mg and Zn;
dry blending LiF particles with the selected starting material, wherein the resulting dry blend comprises from 0.25 to 2.5% by weight LiF;
heating the resulting dry blend at a temperature between about 700° C. and 850° C. for a period of about two hours to about six hours thereby yielding a final composition with a surface treatment of LiF in direct contact with the surface of the composition; and,
preparing a cathode material using the final composition with surface treatment of LiF wherein said cathode material has a capacity greater than 100 mAh/g after 200 cycles when cycled at 60° C. to a complete discharge to an indicated 3 volts over 60 minutes and recharged to an indicated 4.3 volts over 180 minutes.
4. The method of claim 1 , wherein the starting material is selected from the group consisting of: Li 1.06 Al 0.18 Mn 1.76 O 4 , Li 1.06 Cr 0.1 Mn 1.84 O 4 , and Li 1.05 Al 0.12 Mn 1.83 O 4 .
5. The method of claim 1 , wherein the step of dry blending occurs at a temperature between about 10° C. to about 30° C.
6. The method of claim 1 , wherein the step of dry blending continues until the LiF is homogenously distributed.
7. The method of claim 6 , wherein the step of dry blending continues for 20 to 60 minutes and the step of dry blending does not reduce the particle size of the selected starting material or the LiF.
8. The method of claim 1 , wherein the step of heating the dry blend occurs under atmospheric conditions.
9. The method of claim 1 , wherein the resulting final composition has a particle size between about 3 μm to about 30 μm.
10. The method of claim 1 , wherein the resulting final composition comprises from about 0.25 to 2.5% by weight LiF.
11. A method for preparing cathode active material comprising:
selecting a starting material from the group consisting of a cathode active material having the general formula of Li 1+x M y Mn 2−x−y O 4 where 0<x<0.25, 0<y<0.5 and M is one or more trivalent metals from the group Al, Cr, Ga, In and Sc or Li[Li (1−2x)/3 M y Mn (2−x)/3 Ni x−y ]O 2 where 0<x<0.5, 0<y<0.25, x>y and M is one or more metals chosen from Ca, Cu, Mg and Zn;
preparing a slurry of LiF particles in water;
heating the slurry to a temperature between about 40° C. and 60° C.;
blending the selected starting material into the slurry;
stirring the slurry of LiF and starting material until the slurry is a homogeneous dispersion of LiF and starting material;
drying the slurry to isolate the solids;
heating the resulting solids at a temperature between about 450° and 850° for a period sufficient to activate the LiF and to provide a final composition in the form of a cathode active material carrying a surface treatment of LiF in direct contact with the surface of the cathode active material.
12. The method of claim 11 , wherein the starting material is selected from the group consisting of: Li 1.06 Al 0.18 Mn 1.76 O 4 , Li 1.06 Cr 0.1 Mn 1.84 O 4 , and Li 1.05 Al 0.12 Mn 1.83 O 4 .
13. The method of claim 11 , wherein the resulting cathode material has a particle size between about 3 μm to about 30 μm.
14. The method of claim 11 , wherein the resulting cathode material comprises from about 0.25 to 2.5% by weight LiF.
15. The method of claim 11 , further comprising the step of forming a cathode material wherein said cathode material has a capacity greater than 100 mAh/g after 200 cycles when cycled at 60° C. to a complete discharge to an indicated 3 volts over 60 minutes and recharged to an indicated 4.3 volts over 180 minutes.
16. The method of claim 11 , further comprising the step of drying the solids removed from said slurry, said drying step taking place at a temperature between about 50° C. and 140° C.
17. A composition comprising:
a cathode active material having the general formula of Li 1+x M y Mn 2−x−y O 4 where 0<x<0.25, 0<y<0.5 and M is one or more trivalent metals from the group Al, Cr, Ga, In and Sc or Li[Li (1−2x)/3 M y Mn (2−x)/3 Ni x−y ]O 2 where 0<x<0.5, 0<y<0.25, x>y and M is one or more metals chosen from Ca, Cu, Mg and Zn;
a surface treatment of LiF carried on the surface of said cathode active material and in direct contact with said surface of said cathode active material wherein said cathode composition has x-ray diffraction peaks at 38.6, 44.84, and 65.46.
18. The method of claim 11 , wherein the starting material is selected from the group consisting of: Li 1.06 Al 0.18 Mn 1.76 O 4 , Li 1.06 Cr 0.1 Mn 1.84 O 4 , and Li 1.05 Al 0.12 Mn 1.83 O 4 .
19. The composition of claim 17 , wherein said composition is substantially free of Mn 2 O 3 .
20. The cathode composition of claim 17 , wherein from 0.25 to 2.5 percent by weight of said cathode composition is LiF.
21. The cathode composition of claim 17 , wherein the resulting cathode composition has a median particle size between about 3 μm and about 30 μm.
22. A cathode composition comprising:
a cathode active material having the general formula of Li 1+x M y Mn 2−x−y O 4 where 0<x<0.25, 0<y<0.5 and M is one or more trivalent metals from the group Al, Cr, Ga, In and Sc or Li[Li (1−2x)/3 M y Mn (2−x)/3 Ni x−y ]O 2 where 0<x<0.5, 0<y<0.25, x>y and M is one or more metals chosen from Ca, Cu, Mg and Zn;
a surface treatment of LiF on the surface of said cathode active material and in direct contact with the surface of said cathode active material; and,
wherein said cathode composition has a capacity greater than 100 mAh/g after 200 cycles.
23. The method of claim 22 , wherein the starting material is selected from the group consisting of: Li 1.06 Al 0.18 Mn 1.76 O 4 , Li 1.06 Cr 0.1 Mn 1.84 O 4 , and Li 1.05 Al 0.12 Mn 1.83 O 4 .
24. The cathode composition of claim 22 , wherein said cathode composition comprises from about 0.25% to about 2.5% LiF by weight.
25. The cathode composition of claim 22 further comprising from about 0.1% to about 15% by weight of a doping metal.
26. The cathode composition of claim 25 , wherein said doping metal is selected from the group consisting of: Mg, Al, Cr, Fe, Ni, Co, Ga, In, Sc, In, Cu or Zn.
27. The method of claim 2 , wherein the starting material is selected from the group consisting of: Li 1.06 Al 0.18 Mn 1.76 O 4 , Li 1.06 Cr 0.1 Mn 1.84 O 4 , and Li 1.05 Al 0.12 Mn 1.83 O 4 .
28. The method of claim 2 , wherein the step of dry blending occurs at a temperature between about 10° C. to about 30° C.
29. The method of claim 2 , wherein the step of dry blending continues until the LiF is homogenously distributed.
30. The method of claim 2 , wherein the step of dry blending continues for 20 to 60 minutes and the step of dry blending does not reduce the particle size of the selected starting material or the LiF.
31. The method of claim 2 , wherein the step of heating the dry blend occurs under atmospheric conditions.
32. The method of claim 2 , wherein the resulting final composition has a particle size between about 3 μm to about 30 μm.
33. The method of claim 2 , wherein the resulting final composition comprises from about 0.25 to 2.5% by weight LiF.
34. The method of claim 3 , wherein the starting material is selected from the group consisting of: Li 1.06 Al 0.18 Mn 1.76 O 4 , Li 1.06 Cr 0.1 Mn 1.84 O 4 , and Li 1.05 Al 0.12 Mn 1.83 O 4 .
35. The method of claim 3 , wherein the step of dry blending occurs at a temperature between about 10° C. to about 30° C.
36. The method of claim 3 , wherein the step of dry blending continues until the LiF is homogenously distributed.
37. The method of claim 3 , wherein the step of dry blending continues for 20 to 60 minutes and the step of dry blending does not reduce the particle size of the selected starting material or the LiF.
38. The method of claim 3 , wherein the step of heating the dry blend occurs under atmospheric conditions.
39. The method of claim 3 , wherein the resulting final composition has a particle size between about 3 μm to about 30 μm.
40. The method of claim 3 , wherein the resulting final composition comprises from about 0.25 to 2.5% by weight LiF.