PROCESS FOR MAKING LITHIATED TRANSITION METAL OXIDE PARTICLES, AND PARTICLES MANUFACTURED ACCORDING TO SAID PROCESS

Abstract

Process for making lithiated transition metal oxide particles comprising the steps of: (a) Providing a particulate mixed transition metal precursor comprising Ni and at least one transition metal selected from Co and Mn, and, optionally, at least one further metal selected from Ti, Zr, Mo, W, Al, Mg, Nb, and Ta, (b) mixing said precursor with at least one compound of lithium and at least el one processing additive comprising potassium, (c) treating the mixture obtained according to step (b) at a temperature in the range of from 700 to 1,000° C.

Claims

1. A process for making lithiated transition metal oxide particles comprising the steps of: (a) providing a particulate mixed transition metal precursor chosen from hydroxides, carbonates, oxyhydroxides, and oxides of TM, wherein TM is a combination of metals according to general formula (I)
(Ni.sub.aCo.sub.bMn.sub.c).sub.1−dM.sub.d  (I) wherein a ranges from 0.6 to 0.95, b ranges from 0.025 to 0.2, c ranges from zero to 0.2, and d ranges from zero to 0.1, M is chosen from Mg, Al, Ti, Zr, Mo, W, Al, Mg, Nb, and Ta, a+b+c=1, (b) mixing the precursor with at least one compounds of lithium and 0.05 wt. % to 5 wt. % by weight at least of one processing additives chosen from potassium carbonate and potassium bicarbonate, the percentage referring to the entire mixture obtained in step (b), and (c) treating the mixture obtained according to step (b) at a temperature from 700° C. to 1,000° C.

2. The process according to claim 1, wherein the compound of lithium is chosen from lithium oxide, lithium hydroxide, lithium carbonate, and lithium bicarbonate.

3. The process according to claim 1, wherein step (c) is performed in a roller hearth kiln, in a rotary kiln, in a pusher kiln, in a vertical, or tunnel kiln or in a pendulum kiln.

4. The process according to claim 1, wherein step (b) includes the addition adding and mixing of at least one compound of aluminum, titanium, or zirconium.

5. The process according to claim 1, wherein the processing additive has an average particle diameter (d50) ranging from 1 μm to 50 μm.

6. The process according to claim 1, wherein TM is chosen from Ni.sub.0.6Co.sub.0.2Mn.sub.0.2, Ni.sub.0.7Co.sub.0.2Mn.sub.0.1, Ni.sub.0.8Co.sub.0.1Mn.sub.0.1, and Ni.sub.0.85Co.sub.0.1Mn.sub.0.05.

7. The process according to claim 1, wherein step (c) is performed in air, oxygen enriched air, or oxygen atmosphere.

8. The process according to claim 1, wherein the process further comprises step (d): d) treating the particulate material obtained from (c) with an aqueous medium, followed by removing the aqueous medium by a solid-liquid separation method.

9. A particulate electrode active material according to general formula Li.sub.1+xK.sub.yTM.sub.1−x−yO2, wherein x ranges from zero to 0.2, wherein y ranges from 0.002 to 0.1, wherein TM is a combination of metals according to general formula (I)
(Ni.sub.aCo.sub.bMn.sub.c).sub.1−dM.sub.d  (I) wherein a ranges from 0.6 to 0.95, b ranges from 0.025 to 0.2, c ranges from zero to 0.2, and d ranges from zero to 0.1, M is chosen from Mg, Al, Ti, Zr, Mo, W, Al, Mg, Nb, and Ta, a+b+c=1 and wherein an average diameter d50 of primary particles ranges from 2 μm to 15 μm.

10. The particulate electrode active material according to claim 9, wherein secondary particles are composed of 2 to 35 primary particles on average.

11. The particulate electrode active material according to claim 9, wherein potassium ions (K+) occupy lithium ion (Li+) sites in a crystal structure.

12. A method of using a particulate electrode active material according to claim 9 in a lithium ion battery.

Description

GENERAL

[0146] A JOEL-JSM6320F scanning electron microscope (SEM) with energy dispersive spectroscopy (EDS) capability was used to study the phase distribution, composition, rough estimate of primary particle size and surface morphology.

[0147] Percentages are % by weight unless specifically expressed otherwise.

[0148] I.1 Synthesis of a Precursor TM-OH.1, Step (a.1)

[0149] A 9-l-stirred reactor with overflow for removing mother liquor was filled with distilled water and 36.7 g of ammonium sulfate per kg of water. The solution was heated to 45° C. and the pH value is adjusted to 11.6 by adding an aqueous 25 wt. % of sodium hydroxide solution.

[0150] The precipitation reaction was started by the simultaneous feed of an aqueous transition metal solution and an alkaline precipitation agent at a flow rate ratio of 1.84, and a total flow rate resulting in a residence time of 5 hours. The transition metal solution contained the sulfates of Ni, Co and Mn at a molar ratio of 8:1:1 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 8.29. The pH value was kept at 11.6 by the separate feed of 25 wt. % sodium hydroxide solution. Precursor TM-OH.1 was obtained by filtration of the resulting suspension, washed with distilled water, followed by drying at 120° C. in air over a period of 12 hours and sieving.

[0151] I.2 Conversion of TM-OH.1 into a Cathode Active Materials

[0152] I.2.1 Manufacture of a Comparative Cathode Active Material, C-CAM.1

[0153] In a SPEX CETRIPREP 8000 mixer/miller, 5 grams of TM-OH.1 were mixed mechanically with 1.4 grams of LiOH for 20 minutes. The resulting powdered mixture was then calcined in a muffle oven at 850° C. for 15 hours. The resulting C-CAM.1 was then cooled to 25° C. and ground in a mortar/pestle.

[0154] I.2.2 Manufacture of an Inventive Cathode Active Material, CAM.2

[0155] In a SPEX CETRIPREP 8000 mixer/miller, 5 grams of TM-OH.1 were mixed mechanically with 1.4 grams of LiOH and 0.1 g of K.sub.2CO.sub.3 (1.5% by weight) for 20 minutes. The resulting powdered mixture was then calcined in a muffle oven at 850° C. for 15 hours. The resulting CAM.2 was then cooled to 25° C. and ground in a mortar/pestle.

[0156] I.2.3 Manufacture of an Inventive Cathode Active Material, CAM.3

[0157] In a SPEX CETRIPREP 8000 mixer/miller, 5 grams of TM-OH.1 were mixed mechanically with 1.4 grams of LiOH and 0.1 g of K.sub.2CO.sub.3 (1.5% by weight) for 20 minutes. The resulting powdered mixture was then calcined in a muffle oven at 810° C. for 10 hours. The resulting CAM.3 was then cooled to 25° C. and ground in a mortar/pestle.

[0158] II. Testing of Cathode Active Materials

[0159] Inventive and comparative cathode active materials are studied for capacity levels and cycle life in CR2032 coin cells using lithium metal as counter electrode. The lithiated composite materials are formed into a cathode powder for testing by mixing with carbon Super 65 from Timcal (7.5 w %), graphite KS10 from Timcal (7.5%) and 6% PVDF (Kynar) binder. Anhydrous solvent (1-methyl-2pyrrolidinone) was then added to the powder mix to form a slurry. The slurry was then coated on an aluminum substrate. The coating was dried at 85° C. for several hours and calendared to the final thickness (about.60 μm).

[0160] In the coin cells, cathode and anode were separated by a microporous polypropylene separator (MTI corporation) that was wetted with electrolyte consisting of a 1M solution of LiPF.sub.6 dissolved in a 1:1:1 volume mixture of ethylene carbonate (EC), dimethyl carbonate (DMC), and diethyl carbonate (DEC) from Novolyte Corporation. The cell was crimped and used to probe the capacity and cycle life of the lithiated composite material. Cell assembly and crimping was done in glove box.

[0161] Tests of the cathode materials were run at constant current charge and discharge (0.1 C) to determine capacity and cycleability using Solatron 1470 Battery Test Unit and Arbin Instruments battery testerpower system. The coin cells were charged and discharged at a voltage between 4.3V and 3.0V. The cycling performance test was performed with a charge and discharge current each at 18 mA/g.

[0162] Coin cells based on CAM.2 or CAM.3 displayed a superior performance over those based on CCAM.1.