Cathode material and process
The present invention belongs to the field of battery materials, and relates to a process for preparing a particulate lithium manganese nickel spinel compound, and materials produced by the process. The process of the invention uses Mn-containing precursors, Ni-containing precursors, Li-containing precursors and optionally M-containing precursor which form substantially no NOx gases during calcination. The particulate lithium manganese nickel spinel compound product of the process may find use in a lithium ion battery.
1. A process for the preparation of a particulate lithium manganese nickel spinel compound, the process comprising:
(a) milling a composition comprising a Mn-containing precursor, a Ni-containing precursor and a Li-containing precursor, wherein the Mn-containing precursor before milling has a D 90 particle size of from about 2.0 μm to about 4.0 μm; and
(b) calcining the product of step (a);
wherein substantially no NO x gases are formed during the calcination in step (b) beyond impurities or trace amounts obviating the need for exhaust gas treatment, wherein NO x gases comprise NO, NO 2 or a mixture thereof.
2. The process according to claim 1 , wherein the amount of NO x produced during the calcination is such that the concentration of NO x in the exhaust gas from calcination is less than 50 ppm.
3. The process according to claim 1 , wherein the D 90 particle size of the Mn-containing precursor is 2 μm to 3 μm; and/or
wherein the D 50 particle size of the Mn-containing precursor is less than 2 μm; and/or
wherein the D 10 particle size of the Mn-containing precursor is less than 1 μm.
4. The process according to claim 1 , wherein the Mn-containing precursor has a D 90 particle size of from about 2.0 μm to about 4.0 μm, a D 50 particle size of from about 1.0 μm to about 1.5 μm and a D 10 particle size of from about 0.5 μm to about 1.0 μm.
5. The process according to claim 1 , wherein the particulate lithium manganese nickel spinel compound has a D 10 particle size of from about 1.0 μm to about 3.0 μm; and/or
wherein the particulate lithium manganese nickel spinel compound has a D 90 particle size of from about 8.0 μm to about 15.0 μm.
6. The process according to claim 1 , wherein the Mn-containing precursor comprises MnCO 3 ; and/or
wherein the Ni-containing precursor comprises Ni(OH) 2 or a hydrated form thereof; and/or
wherein the Li-containing precursor comprises LiOH or a hydrated form thereof.
7. The process according to claim 1 , wherein the composition is a slurry comprising a solvent, the Mn-containing precursor, the Ni-containing precursor, and the Li-containing precursor.
8. The process according to claim 7 , further comprising a step of drying the slurry after the milling step (a) and before the calcining step (b).
9. The process according to claim 1 , wherein step (a) is carried out in a Pearl mill.
10. The process according to claim 1 , wherein in step (b) calcination is performed at a temperature of 350-950° C.
11. The process according to claim 1 , wherein the particulate lithium manganese nickel spinel compound has a composition according to Formula I:
Li x Mn y Ni z M a O b Formula I
wherein: M is one or more elements that are Al, Mg, Ti, Co, Cu or Cr;
0.8≤x≤1.2;
y=2−z−a;
0.2<z<1.2;
0≤a≤0.06; and
3.5≤b≤4.5.
12. A process according to claim 11 , wherein
0.9≤x≤1.1;
0.3<z<0.5;
0.04≤a≤0.06; and
3.9≤b≤4.1;
and wherein M is Al.
13. The process according to claim 1 , further comprising forming a positive active electrode material comprising the lithium manganese nickel spinel compound.
14. The process according to claim 13 , further comprising forming an electrode comprising the positive active electrode material according to claim 13 .
15. The process according to claim 14 , further comprising constructing a lithium secondary cell or battery comprising the electrode according to claim 14 .
16. The process according to claim 1 , wherein the composition further comprises an M-containing precursor, wherein M is one or more elements that are Al, Mg, Ti, Co, Cu or Cr.
17. The process according to claim 16 , wherein the Mn-containing precursor, Ni-containing precursor, or Li-containing precursor contains two or more of Mn, Ni or M.
18. The process according to claim 16 , wherein each of the Mn-containing precursor, Ni-containing precursor, Li-containing precursor and M-containing precursor contain less than 5 wt % nitrate with respect to the weight of metal element in the precursor.
19. The process according to claim 16 , further comprising preparing a slurry comprising a solvent, an Mn-containing precursor, a Ni-containing precursor, a Li-containing precursor and an M-containing precursor before step (a).
20. The process according to claim 16 , wherein the M-containing precursor comprises an Al-containing precursor.