Positive electrode additive, manufacturing method thereof, and positive electrode and lithium rechargeable battery including the same

Patent metadata

Field	Value
Publication number	US-12249714-B2
Application number	US-202017274860-A
Country	US
Kind code	B2
Filing date	Mar 3, 2020
Priority date	May 27, 2019
Publication date	Mar 11, 2025
Grant date	Mar 11, 2025

Abstract

The present disclosure relates to a positive electrode additive, a manufacturing method thereof, and a positive electrode and a lithium rechargeable battery including the same. Specifically, one embodiment of the present disclosure provides a positive electrode additive for a lithium rechargeable battery comprising: a compound represented by the following Chemical Formula 1; a compound represented by the following Chemical Formula 2; and lithium phosphate (Li 3 PO 4 ):

Li 2+a Ni b M 1−b O 2+c   [Chemical Formula 1]
wherein, M is a metal element forming a divalent cation, −0.2≤a≤0.2, 0.5≤b≤1.0, and −0.2≤c≤0.2,

Ni 2−e M 1−e P 4 O 12   [Chemical Formula 2]
wherein, 0.5≤e≤1.0, and M is the same as defined in Chemical Formula 1.

First claim

The invention claimed is:

1. A positive electrode additive for a lithium rechargeable battery comprising:
a compound represented by the following Chemical Formula 1;
a compound represented by the following Chemical Formula 2; and
lithium phosphate (Li 3 PO 4 )
Li 2+a Ni b M 1−b O 2+c   [Chemical Formula 1]

wherein, M is a metal element forming a divalent cation, −0.2≤a≤0.2, 0.5≤b≤1.0, and −0.2≤c≤0.2,
Ni 2−e M 1−e P 4 O 12   [Chemical Formula 2]

wherein, 0.5<e<1.0, and M is the same as defined in Chemical Formula 1,
wherein the compound represented by Chemical Formula 1 is included in an amount of 80 to 90% by weight, and the Li 3 PO 4 is included in an amount of 2 to 5% by weight, each based on the total amount (100% by weight) of the positive electrode additive.

2. The positive electrode additive for a lithium rechargeable battery according to claim 1 ,
wherein the compound represented by Chemical Formula 2 is dissolved in an electrolyte containing a lithium salt and an organic solvent.

3. The positive electrode additive for a lithium rechargeable battery according to claim 1 ,
wherein in the positive electrode additive,
the compound represented by Chemical Formula 1 forms a secondary particle, and the lithium phosphate particle is attached to the surface of the secondary particle.

4. The positive electrode additive for a lithium rechargeable battery according to claim 1 ,
wherein the positive electrode additive further comprises Li 2 O and NiO.

5. A method for manufacturing the positive electrode additive for a lithium rechargeable battery according to any one of claims 1 to 4 , comprising the steps of:
preparing a raw material mixture containing a lithium raw material, a nickel raw material, and a phosphorus raw material; and
heat-treating the raw material mixture at a temperature in the range of 600 to 900° C. in a reactor into which an inert gas is supplied at a flow rate of 1.5 to 2.5 L/min.

6. The method for manufacturing a positive electrode additive for a lithium rechargeable battery according to claim 5 ,
wherein the inert gas includes nitrogen (N 2 ) gas.

7. The method for manufacturing a positive electrode additive for a lithium rechargeable battery according to claim 5 ,
wherein in the raw material mixture, a molar ratio of lithium (Li): nickel (Ni) constituting the lithium raw material and the nickel raw is 3:1 to 3:2.

8. The method for manufacturing a positive electrode additive for a lithium rechargeable battery according to claim 5 ,
wherein the phosphorus raw material is contained in an amount of 1 to 10% by weight based on the total amount (100% by weight) of the raw material mixture.

9. The method for manufacturing a positive electrode additive for a lithium rechargeable battery according to claim 5 ,
wherein the phosphorus raw material includes secondary ammonium phosphate ((NH 4 ) 2 HPO 4 ), primary ammonium phosphate (NH 4 H 2 PO 4 ), or a mixture thereof.

10. The method for manufacturing a positive electrode additive for a lithium rechargeable battery according to claim 5 ,
wherein the step of heat-treating the raw material mixture at a temperature in the range of 600 to 900° C. in a reactor to which an inert gas is supplied, comprises the following steps:
a) reacting the lithium raw material and the nickel raw material to produce a compound represented by the following Chemical Formula 1;
b) reacting the nickel raw material that has not reacted in step a) with the phosphorous raw material to produce a compound represented by the following Chemical Formula 2;
c) reacting the lithium raw material that has not reacted in step a) with the phosphorus raw material that has not reacted in step b) to produce lithium phosphate (Li 3 PO 4 ); and
d) obtaining a positive electrode additive including the compound represented by Chemical Formula 1 produced in step a), the compound represented by Chemical Formula 2 produced in step b), and the lithium phosphate (Li 3 PO 4 ) produced in step c),
Li 2+a Ni b M 1−b O 2+c   [Chemical Formula 1]

wherein, M is a metal element forming a divalent cation, −0.25a≤0.2, 0.5≤b≤1.0 and −0.2≤c≤0.2,
Ni 2−e M 1−e P 4 O 12   [Chemical Formula 2]

wherein, 0.5≤e≤1.0, and M is the same as defined in Chemical Formula 1.

11. The method for manufacturing a positive electrode additive for a lithium rechargeable battery according to claim 10 ,
wherein the positive electrode additive obtained in step d) also includes a lithium raw material, a nickel raw material, or a mixture thereof which are not reacted in a) to c).

12. A lithium rechargeable battery comprising:
a positive electrode containing the positive electrode additive of claim 1 ;
an electrolyte containing a lithium salt and an organic solvent; and
a negative electrode.

13. The lithium rechargeable battery according to claim 12 ,
wherein during charging formation of the lithium rechargeable battery,
the compound represented by Chemical Formula 2 is eluted from the positive electrode additive, and then reduced to Ni metal on the surface of the negative electrode.

14. The lithium rechargeable battery according to claim 12 ,
wherein 200 to 4000 ppm of Ni metal is detected from the surface of the negative electrode separated after the lithium rechargeable battery is formed and charged up to 4.2 V.

Assignees

• Lg Chemical Ltd
• Lg Energy Solution Ltd

Inventors

• Lee Boram
• Park Sin Young
• Yoo Tae Gu
• Kim Taegon
• Kwak Min
• Jung Wang Mo

Classifications

• H01M2220/20

  Batteries in motive systems, e.g. vehicle, ship, plane · CPC title

• H01M2004/028

  Positive electrodes · CPC title

• H01M10/0567

  characterised by the additives · CPC title

• H01M10/0525

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