Lithium-excess cathode material and co-precipitation formation method
A lithium-excess cathode material according to Li1+xNiaMnbCocModO2−y (0<x<0.3, 0≤a≤1, 0≤b≤1, 0≤c≤1, 0≤d≤0.2, 0≤y≤0.25) in the form of secondary spherical microparticles formed from primary spherical nanoparticles. The primary nanoparticles can in the range of ˜130 nm to 170 nm and the secondary in the range of ˜2-3 μm. A method of formation includes mixing a carbonates or hydroxides solution into a mixed solution of transition metal (M) ions with predetermined stoichiometry under stirring, and aging resulting transition metal carbonates or hydroxides at a predetermined temperature for period of time to produce primary nanoparticles of a predetermined size. A gas-solid interface reaction to uniformly creating oxygen vacancies without affecting structural integrity of Li-excess layered oxides is also provided.
1. A lithium-excess cathode material comprising Li 1+x Ni a Mn b Co c Mo d O 2−y (0<x<0.3, 0≤a≤1, 0≤b≤1, 0≤c≤1, 0≤d≤0.2, 0≤y≤0.25) in the form of secondary spherical microparticles having an average diameter of 2-3 μm formed from primary spherical nanoparticles having diameters in the range of 130 nm to 200 nm.
2. The material of claim 1 , further comprising excess oxygen vacancies in the material.
3. The material of claim 1 , comprising Li 1.2 Ni 0.2 Mn 0.6 O 2 .
4. The material of claim 1 , comprising Li 1.2 N 0.136 Mn 0.544 Co 0.136 O 2 .
5. The material of claim 1 , comprising Li 1.1 Ni 0.2 Mn 0.6 O 1.95 .
6. The material of claim 1 , comprising Li 1.13 Ni 0.3 Mn 0.57 O 2 .
7. The material of claim 1 , comprising Li 1.144 Ni 0.136 Co 0.136 Mn 0.544 O 1.92 .
8. The material of claim 1 , comprising Li 1.18 Ni 0.135 Co 0.135 Mn 0.539 Mo 0.01 O 2 .
9. The material of claim 1 , further comprising a lithium lanthanum titanium oxide coating.
10. The material of claim 1 , as part of a cathode in a lithium ion battery.
11. The electrode material of claim 1 where 0<x<0.3, 0≤a≤1, 0≤b≤1, 0≤c≤1, 0≤d≤0.2, 0≤y≤0.25.
12. A method for forming morphology controlled lithium-excess cathode material, comprising:
mixing a carbonates or hydroxides solution into a mixed solution of transition metal (M) ions with predetermined stoichiometry under stirring to create a slurry of primary metal carbonate or metal hydroxide nanoparticles having diameters in the range of 130 nm to 200 nm;
transferring the slurry to an ageing vessel;
aging the slurry at temperature ranging from 40° C. to 80° C. for 2 to 20 hours to produce secondary microparticles having an average diameter of 2-3 μm or smaller;
washing and then drying a resulting powder;
mixing the powder with a stoichiometric amount of lithium carbonate or lithium hydroxide;
calcinating the mixture to produce the morphology controlled lithium-excess cathode material.
13. The method of claim 12 , wherein said resulting powder comprises Li 1.2 Ni 0.2 Mn 0.6 O 2 (0.5 LiNi 0.5 Mn 0.5 O 2 .0.5 Li 2 MnO 3 ).
14. The method of claim 12 , further comprising coating the mixture with a lithium lanthanum titanium oxide coating.
15. The method of claim 12 , further comprising introducing oxygen vacancies into the morphology controlled lithium-excess cathode material via gas solid interfacial modification.
16. The method of claim 15 , wherein said gas solid interfacial modification comprises placing the lithium-excess cathode material and a CO 2 precursor separate from each other and heating to induce the gas solid interfacial modification and create excess oxygen vacancy morphology controlled lithium-excess cathode material.
17. The method of claim 16 , wherein the CO 2 precursor comprises NH 4 HCO 3 .
18. The method of claim 17 , further comprising washing the oxygen vacancy morphology controlled lithium-excess cathode material.
19. The method of claim 12 , wherein the ageing vessel comprises an autoclave and the ageing is conducted without stirring.
20. The method of claim 12 , wherein the ageing is conducted at a temperature ranging from 70 to 80° C. for 10 to 15 hours.