Cathode additive, preparation method thereof, and cathode and lithium secondary battery comprising the same

Patent metadata

Field	Value
Publication number	US-11545670-B2
Application number	US-201816757783-A
Country	US
Kind code	B2
Filing date	Nov 27, 2018
Priority date	Nov 27, 2017
Publication date	Jan 3, 2023
Grant date	Jan 3, 2023

Abstract

The present disclosure relates to a cathode additive, a method for preparing the same, and a cathode and a lithium secondary battery including the same. More specifically, one embodiment of the present disclosure provides a cathode additive that can offset an irreversible capacity imbalance, increase the initial charge capacity of a cathode, and simultaneously inhibit the generation of a gas in a battery.

First claim

The invention claimed is:

1. A cathode additive comprising:
a core, the composition of which is represented by the following Chemical Formula 1; and
a coating layer positioned on a surface of the core, and comprising a phosphorus (P) compound:
{ x (Li 2+a Ni b M 1−b O 2+c )}·{ y (NiO)}·{ z (Li 2 O)}  [Chemical Formula 1]

wherein, in Chemical Formula 1,
M is one or more metal atoms forming a divalent cation or a trivalent cation,
−0.2≤a≤0.2, 0.5≤b≤1.0, −0.2≤c≤0.2,
0.7≤x≤1.0, 0<y≤0.15, 0<z≤0.15, and x+y+z=1.

2. The cathode additive according to claim 1 , wherein the phosphorus (P) compound includes one or more selected from the group consisting of lithium phosphate (Li 3 PO 4 ) and ammonium phosphate (NH 4 H 2 PO 4 ).

3. The cathode additive according to claim 1 , wherein the coating layer is included in a content of 500 to 9000 ppm, based on a total amount of the cathode additive.

4. The cathode additive according to claim 1 , wherein the core includes a lithium nickel oxide represented by the following Chemical Formula 1-1, nickel oxide (NiO), and lithium oxide (Li 2 O), and has a whole composition represented by the above Chemical Formula 1:
Li 2+a Ni b M 1−b O 2+c   [Chemical Formula 1-1]

wherein, in Chemical Formula 1-1,
M, a, b, and c are as defined in Chemical Formula 1.

5. The cathode additive according to claim 1 , wherein y=z.

6. The cathode additive according to claim 5 , wherein for the core, a peak by lithium oxide (Li 2 O) is detected in at least one of a range which 2θ is 30 to 35°, a range in which 2θ is 35 to 40°, or a range in which 2θ is 55 to 60°, by XRD (X-Ray Diffraction) measurement by Fe Kα X-ray (X-rα).

7. The cathode additive according to claim 5 , wherein a content of lithium oxide (Li 2 O) in a total amount of the core (100 wt %) is greater than 0 wt % and equal to or less than 15 wt %.

8. The cathode additive according to claim 5 , wherein for the core, a peak by nickel oxide (N i O) is detected in at least one of a range in which 2θ is 35 to 40°, a range in which 2θ is 40 to 45°, or a range in which 2θ is 50 to 55°, by XRD (X-Ray Diffraction) measurement by Fe Kα X-ray (X-rα).

9. The cathode additive according to claim 5 , wherein the content of nickel oxide (N i O) in the total amount of the core (100 wt %) is greater than 0 wt % and equal to or less than 15 wt %.

10. A method for preparing the cathode additive of claim 1 , comprising steps of:
preparing a nickel-based oxide represented by the following Chemical Formula 3;
heat treating a mixture of the nickel-based oxide and lithium oxide (Li 2 O) to obtain a core; and
heat treating a mixture of the core and ammonium phosphate (NH 4 H 2 PO 4 ) to form a coating layer on the surface of the core:
(Ni d M 1−d )O 2   [Chemical Formula 3]

wherein, in Chemical Formula 3,
M is a metal atom forming a divalent cation or a trivalent cation, and
0.5≤d≤1.0.

11. The method for preparing a cathode additive according to claim 10 , wherein the step of forming a coating layer on the surface of the core is conducted under an inert atmosphere.

12. The method for preparing a cathode additive according to claim 10 , wherein the step of forming a coating layer on the surface of the core is conducted at 600 to 800° C.

13. The method for preparing a cathode additive according to claim 10 , wherein the step of obtaining the core is conducted under an inert atmosphere.

14. The method for preparing a cathode additive according to claim 10 , wherein the step of obtaining the core is conducted at 600 to 800° C.

15. A cathode mixture comprising:
the cathode additive of claim 1 ; and
a cathode active material.

16. The cathode mixture according to claim 15 , wherein the cathode additive is included in the content of 1 to 30 wt %, based on the total weight of the mixture (100 wt %).

17. The cathode mixture according to claim 15 , wherein the cathode active material includes lithium and one or more composite oxides selected from the group consisting of a metal of cobalt, manganese, nickel, and a combination thereof.

18. The cathode mixture according to claim 15 , further comprising a conductive material, a binder, or a mixture thereof.

19. A lithium secondary battery comprising:
a cathode comprising the cathode mixture of claim 15 ;
an electrolyte; and
an anode.

20. The lithium secondary battery according to claim 19 , wherein the anode includes one or more anode active materials selected from the group consisting of a carbon-based anode active material, as lithium metal, as lithium alloy, Si, SiO x (0<x<2), a Si—C composite, a Si-Q alloy (wherein Q is an alkali metal, an alkali earth metal, an atom of Groups 13 to 16, a transition metal, a rare earth atom, or a combination thereof, provided that it is not Si), Sn, SnO 2 , a Sn—C composite, and a Sn—R (where R is an alkali metal, an alkali earth metal, an atom of Groups 13 to 16, a transition metal, a rare earth metal, or a combination thereof, provided that it is not Sn).

Assignees

• Lg Chemical Ltd
• Lg Energy Solution Ltd

Inventors

• Kim Ji Hye
• Park Byungchun
• Han Jungmin
• Jung Wang Mo

Classifications

• C01G53/42

  containing alkali metals, e.g. LiNiO2 · CPC title

• C01P2006/40

  Electric properties · CPC title

• Y02E60/10

  Energy storage using batteries · CPC title

• C01G53/04

  Oxides · CPC title

• H01M4/525

  of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy · CPC title