Positive electrode material for rechargeable lithium ion batteries

Patent metadata

Field	Value
Publication number	US-11522187-B2
Application number	US-201816956025-A
Country	US
Kind code	B2
Filing date	Dec 4, 2018
Priority date	Dec 22, 2017
Publication date	Dec 6, 2022
Grant date	Dec 6, 2022

Abstract

The invention provides a positive electrode active material for a lithium ion battery, comprising a lithium transition metal-based oxide powder, the powder comprising single crystal monolithic particles comprising Ni and Co and having a general formula Li1+a ((Niz (Ni1/2 Mn1/2)y Cox)1−kAk)1-a 02, wherein A is a dopant, −0.02<a≤0.06, 0.10≤x≤0.35, 0≤z≤0.90, x+y+z=1 and k≤0.01, the particles having a cobalt concentration gradient wherein the particle surface has a higher Co content than the particle center.

First claim

The invention claimed is:

1. A positive electrode active material for a lithium ion battery, comprising a lithium transition metal-based oxide powder, the powder comprising single crystal monolithic particles having a center and a surface and comprising Ni and Co and having a general formula Li 1+a ((Ni z (Ni 1/2 Mn 1/2 ) y Co x ) 1−k A k ) 1−a O 2 , wherein A is a dopant, −0.02<a≤0.06, 0.10≤x≤0.35, 0≤z≤0.90, x+y+z=1 and k≤0.01, the particles having a cobalt concentration gradient wherein the particle surface has a higher Co content than the particle center and wherein either
when Mn is present, the ratio between the Co/Mn molar ratio at the particle surface and the Co/Mn molar ratio at a distance d from the surface is between 1.1 and 1.3, whereby d=¼ of the distance from the particle surface to the particle center, or
when Mn is absent, the ratio between C(4)/C(3) is between 1.1 and 1.3, wherein C(4) is the ratio between the molar concentration of Co at the particle surface and the molar concentration of Co at the particle center, and wherein C(3) is the ratio between a) the Co molar concentration at ¾ distance from the particle surface to the particle center and b) the molar concentration of Co at the particle center.

2. The positive electrode active material of claim 1 , wherein the powder has a particle size distribution with D50<10 μm.

3. The positive electrode active material of claim 1 , wherein when Mn is present, the ratio between the Co/Mn molar ratio at the particle surface and the Co/Mn molar ratio at the particle center is between 1.4 and 1.5.

4. The positive electrode active material of claim 1 , wherein the cobalt concentration gradient varies continuously from the surface to the center of the particles.

5. The positive electrode active material of claim 1 , wherein the particles have a morphology with multiple flat surfaces and an aspect ratio of at least 0.8.

6. The positive electrode active material of claim 1 , wherein the particles have a surface layer comprising LiCoO 2 .

7. The positive electrode active material of claim 1 , wherein the particles have a coating comprising either one or both of LiNaSO 4 and Al 2 O 3 .

8. A solid state lithium ion battery or a lithium ion battery provided with a liquid electrolyte comprising the positive electrode material of claim 1 , wherein the battery is cycled up to a voltage of at least 4.35V.

9. A method for manufacturing the powderous positive electrode material of claim 1 , comprising Ni and Co and having a general formula Li 1+a ((Ni z (Ni 1/2 Mn 1/2 ) y Co x ) 1−k A k ) 1−a O 2 , wherein A is a dopant, −0.02<a≤0.06, 0.10≤x≤0.35, 0≤z≤0.90, x+y+z=1 and k≤0.01, comprising the steps of:
providing a first precursor comprising A, Ni and Co, and Mn, if present in the powderous positive electrode material, the precursor comprising particles having a particle size distribution with a D50<10 μm,
mixing the first precursor with either one of LiOH, Li 2 O, Li 2 CO 3 or LiOH.H 2 O, thereby obtaining a first mixture, wherein the Li to transition metal ratio LM1 in the first mixture is between 0.60 and <1.00,
sintering the first mixture in an oxidizing atmosphere at a temperature between 700° C. and 900° C., for a time between 6 and 36 hrs, thereby obtaining a first intermediate product,
mixing the first intermediate product with either one of LiOH, Li 2 O, Li 2 CO 3 or LiOH.H 2 O thereby obtaining a second mixture, wherein the Li to transition metal ratio in the second mixture LM2≥0.90,
sintering the second mixture in an oxidizing atmosphere at a temperature between (950−(155.56*z))° C. and (1050−(155.56*z))° C., for a time between 6 and 36 hrs,
milling the sintered second mixture whereby the sintered second mixture particles are separated in solitary primary particles,
providing a Co-based precursor and mixing said Co-based precursors with the sintered and milled second mixture, thereby obtaining a third mixture having a Li to transition metal ratio in the third mixture LM3 with −0.107*z+1.018≤LM3≤−0.107*z+1.098,
sintering the third mixture in an oxidizing atmosphere at a temperature between 700° C. and 800° C., for a time between 6 and 36 hrs.

10. The method according to claim 9 , further comprising in the step of providing a Co-based precursor and mixing said precursors with the sintered and milled second mixture, additionally adding a Li-based precursor.

11. The method according to claim 9 , wherein y>0, z≥0.35 and −0.012≤a≤0.010, LM1 is between 0.60 and 0.95, LM2≥LM1 and LM3≥LM1, and the second sintering temperature is between 895° C. and 995° C.

12. The method according to claim 9 , wherein LM3=LM2.

13. The method according to claim 11 , wherein between 2 and 10 mol % of Co is added in the Co-based precursor, wherein the mol % Co is expressed versus the total metal content except Li in the second mixture.

14. The method according to claim 9 , wherein the milling step is performed using a ball mill equipment, which is applied to break agglomerated powder obtained after sintering the second mixture into separate particles .

15. The method according to claim 9 , further comprising the subsequent steps of:
providing an inorganic oxidizing chemical compound,
providing a chemical that is a Li-acceptor,
mixing the sintered third mixture, the oxidizing compound and the Li-acceptor, thereby obtaining a fourth mixture, and
heating the fourth mixture at a temperature between 300 and 800° C. in an oxygen comprising atmosphere.

16. The method according to claim 15 , wherein both the inorganic oxidizing chemical compound and the Li-acceptor chemical are the same compound, being either one of Li 2 S 2 O 8 , H 2 S 2 O 8 and Na 2 S 2 O 8 , and the heating temperature of the fourth mixture is between 350 and 450° C.

17. The method according to claim 15 , wherein a nanosized Al 2 O 3 powder is provided as a further Li-acceptor chemical.

Assignees

• Umicore Nv
• Umicore Korea Ltd

Inventors

• Celasun Yagmur
• Paulsen Jens
• Kumakura Shinichi
• Park Areum
• Lee Jukyoung
• Yang Taehyeon

Classifications

• H01M4/1391

  of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title

• C01P2004/61

  Micrometer sized, i.e. from 1-100 micrometer · CPC title

• C01P2004/54

  Particles characterised by their aspect ratio, i.e. the ratio of sizes in the longest to the shortest dimension · CPC title

• H01M4/505

  of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title