PROCESS FOR COATING AN OXIDE MATERIAL

Abstract

The present disclosure relates to a process for coating an oxide material, process comprising: (a) providing a particulate material chosen from lithiated nickel-cobalt aluminum oxides, lithiated cobalt-manganese oxides, and lithiated layered nickel-cobalt-manganese oxides, (b) treating the cathode active material with a metal alkoxide, a metal halide, a metal chloride, a metal amide, or an alkyl metal compound, (c) treating the material obtained in step (b) with a gas containing HF, and, optionally, repeating the sequence of steps (b) and (c), wherein step (b) is carried out in a mechanical mixer, or step (b) is carried out using a moving bed or fixed bed wherein steps (b) and (c) are carried out at a pressure that is in the range of from 5 mbar to 1 bar above ambient pressure.

Claims

1-13. (canceled)

14. A process for making a coated oxide material comprising: (a) providing a particulate material chosen from lithiated nickel-cobalt aluminum oxides, lithiated cobalt-manganese oxides, and lithiated layered nickel-cobalt-manganese oxides for generating a cathode active material, (b) treating the cathode active material with a metal alkoxide, a metal amide, a metal hydride, a metal halide, or an alkyl metal compound in the gas phase, and (c) treating the material obtained in step (b) with gas containing HF, and, optionally, repeating the sequence of steps (b) and (c), wherein step (b) is carried out in a mechanical mixer, or step (b) is carried out using a moving bed or a fixed bed, and wherein steps (b) and (c) are carried out at a pressure that ranges from 5 mbar to 1 bar above ambient pressure.

15. The process according to claim 14, wherein the mixer is chosen from compulsory mixers and free-fall mixers.

16. The process according to claim 14, wherein step (c) is carried out in an atmosphere that is free from carbon dioxide.

17. The process according to claim 14, wherein the alkyl metal compound, the metal alkoxide, the metal amide, the metal hydride, and the metal halide are each respectively chosen from M.sup.1(R.sup.1).sub.2, M.sup.2(R.sup.1).sub.3, M.sup.3(R.sup.1).sub.4yH.sub.y, M.sup.1(OR.sup.2).sub.2, M.sup.2(OR.sup.2).sub.3, M.sup.3(OR.sup.2).sub.4, M.sup.3[N(R.sup.2).sub.2].sub.4, M.sup.1(R.sup.1)X, M.sup.2(R.sup.1).sub.2X, M.sup.2R.sup.1X.sub.2, M.sup.3(R.sup.1).sub.3X, M.sup.3(R.sup.1).sub.2X.sub.2, M.sup.3R.sup.1X.sub.3, M.sup.2H.sub.3, M.sup.3H.sub.4, (M.sup.3).sub.2H.sub.6, M.sup.2Cl.sub.3, M.sup.3Cl.sub.4, M.sup.3.sub.2X.sub.6, combinations of M.sup.1 or M.sup.2 or M.sup.3 with combinations of counterions, and methyl alumoxane, wherein each R.sup.1 is independently chosen from hydride, straight-chain C.sub.1-C.sub.8-alkyl, and branched C.sub.1-C.sub.8-alkyl, each R.sup.2 is independently chosen from straight-chain C.sub.1-C.sub.4-alkyl and branched C.sub.1-C.sub.4-alkyl, M.sup.1 is chosen from Mg and Zn, M.sup.2 is chosen from Al and B, M.sup.3 is chosen from Si, Sn, Ti, Zr, and Hf, X is halide chosen from chloride, bromide, and iodide, and the variable y is an integer ranging from zero to 4.

18. The process according to claim 14, wherein the lithiated layered nickel-cobalt-manganese oxide is a material of general formula (I)
Li.sub.(1+x)[Ni.sub.aCo.sub.bMn.sub.cM.sup.4.sub.d].sub.(1x)O.sub.2 (I) wherein M.sup.4 is chosen from Mg, Ca, Ba, Al, Ti, Zr, Zn, Mo, Nb, V and Fe,
zerox0.2
0.1a0.95,
zero<b0.5,
0.1c0.6,
zerod0.1, and
a+b+c+d=1.

19. The process according to claim 14, wherein steps (b) and (c) are performed in a rotating vessel that has baffles.

20. The process according to claim 14, wherein the exhaust gasses are treated with water at a pressure above ambient pressure.

21. The process according to claim 20, wherein the exhaust gasses are treated with water at a pressure ranging from 5 mbar to 1 bar above ambient pressure.

22. The process according to claim 14, wherein step (b) is carried out at a pressure ranging from 5 to 350 mbar above ambient pressure.

23. The process according to claim 14, wherein the particulate material is lithiated nickel-cobalt aluminum oxide or lithiated layered nickel-cobalt-manganese oxide, and each are cohesive.

24. The process according to claim 14, wherein step (b) is performed at a temperature ranging from 15 C. to 350 C.

25. The process according to claim 14, wherein the reactor in which step (b) is carried out is flushed with an inert gas between steps (b) and (c).

26. The process according to claim 14, further comprising removing the coated material from the reactor in which steps (b) and (c) are carried out, respectively, by pneumatic convection.

Description

[0084] I. Cathode Active Materials

[0085] I.1. Preparation of a Precursor for Cathode Active Materials

[0086] A stirred tank reactor was filled with deionized water. The precipitation of mixed transition metal hydroxide precursor was started by simultaneous feed of an aqueous transition metal solution and an alkaline precipitation agent at a flow rate ratio of 1.9, and a total flow rate resulting in a residence time of 8 hours. The aqueous transition metal solution contained Ni, Co and Mn at a molar ratio of 6:2:2 as sulfates each and a total transition metal concentration of 1.65 mol/kg. The alkaline precipitation agent consisted of 25 wt. % sodium hydroxide solution and 25 wt. % ammonia solution in a weight ratio of 25. The pH value was kept at 11.9 by separate feed of an aqueous sodium hydroxide solution. After stabilization of particle size the resulting suspension was removed continuously from the stirred vessel. The mixed transition metal (TM) oxyhydroxide precursor was obtained by filtration of the resulting suspension, washing with distilled water, drying at 120 C. in air and sieving.

[0087] I.2. Manufacture of Cathode Active Materials

[0088] C-CAM.1 (Comparative): The mixed transition metal oxyhydroxide precursor obtained according to I.1 was mixed with Al.sub.2O.sub.3 (average particle diameter 6 nm) and LiOH monohydrate to obtain a concentration of 0.3 mole-% Al relative to Ni+Co+Mn+Al and a Li/(TM+Al) molar ratio of 1.03. The mixture was heated to 885 C. and kept for 8 hours in a forced flow of oxygen to obtain the electrode active material C-CAM 1.

[0089] D50=9.5 m determined using the technique of laser diffraction in a Mastersize 3000 instrument from Malvern Instruments. The Al-content was determined by ICP analytics and corresponded to 820 ppm. Residual moisture at 250 C. was determined to be 300 ppm.

[0090] CAM.2 (inventive): A fluidized bed reactor with external heating jacket is charged with 100 g of C-CAM.1, and at an average pressure of 1030 mbar, C-CAM.1 is fluidized. The fluidized bed reactor is heated to 180 C. and kept at 180 C. for 3 h.

[0091] Step (b.1): Trimethylaluminum (TMA) in the gaseous state is introduced into the fluidized bed reactor through a filter plate by opening a valve to a precursor reservoir that contained TMA in liquid form and that is kept at 50 C. The TMA is diluted with nitrogen as carrier gas. The gas flow of TMA and N.sub.2 is 10 sccm. After a reaction period of 210 seconds non-reacted TMA is removed through the nitrogen stream, and the reactor is purged with nitrogen for 15 minutes with a flow of 30 sccm.

[0092] Step (c.1): Then, the pressure is set to 1030 mbar. Hydrogen fluoride in the gaseous state is introduced into the fluidized bed reactor by opening a valve to a reservoir that contained liquid HF kept at 24 C., flow: 10 sccm. After a reaction period of 120 seconds non-reacted HF is removed through a nitrogen stream, and the reactor was purged with nitrogen, 15 minutes at 30 sccm.

[0093] The above treatment with TMA and HF including the nitrogen purging is repeated 3 times.

[0094] Inventive coated oxide material CAM.2 is obtained.