Cathode active material for lithium secondary battery

Patent metadata

Field	Value
Publication number	US-10529985-B2
Application number	US-201816058594-A
Country	US
Kind code	B2
Filing date	Aug 8, 2018
Priority date	Oct 29, 2013
Publication date	Jan 7, 2020
Grant date	Jan 7, 2020

Abstract

Also, a coating layer may be formed in which the lithium boron oxide is uniformly coated in an amount proportional to the used amount of the boron-containing compound even at a low heat treatment temperature.

First claim

The invention claimed is:

1. A cathode active material comprising:
a core-shell structure having a core and a coating layer disposed on the surface of the core,
wherein the core consists of a lithium transition metal oxide and optionally lithium impurities which result from the synthesis of the lithium transition metal oxide; and
wherein the coating layer having an inner surface and an outer surface separated by a thickness, the inner surface facing the core,
wherein the coating layer consists of a lithium boron oxide and the lithium impurities, the lithium impurities present in the coating layer only at the inner surface,
wherein the lithium boron oxide is LiBO 2 , Li 2 B 4 O 7 , or a mixture thereof,
wherein the lithium impurities include at least one of Li 2 CO 3 and LiOH,
wherein the lithium impurities are present in an amount of less than 0.3 wt % based on a total weight of the cathode active material, and
wherein the lithium transition metal oxide is represented by Chemical Formula 3, and, in Chemical Formula 3, w has a concentration gradient gradually decreasing from the surface of the lithium transition metal oxide to inside thereof:
Li 1+a [Ni x Mn y Co z B w M v ]O 2−c A c   <Chemical Formula 3>

where M is any one selected from the group consisting of aluminum (Al), zirconium (Zr), zinc (Zn), titanium (Ti), magnesium (Mg), gallium (Ga), and indium (In), or two or more elements thereof; A is at least one selected from the group consisting of phosphorus (P), fluorine (F), sulfur (S), and nitrogen (N), and 0≤x≤1.0, 0≤y≤0.6, 0≤z≤0.6, 0≤v≤0.1, 0≤a<0.3, 0≤c≤0.2, a+x+y+z+v=1, and 0<w≤0.1.

2. The cathode active material of claim 1 , wherein elemental boron (B) in an amount of 100 parts per million (ppm) to 2,000 ppm, based on a total mass of the cathode active material.

3. The cathode active material of claim 1 , wherein the coating layer comprises elemental B in an amount of 250 parts per million (ppm) to 1,100 ppm, based on a total mass of the cathode active material.

4. The cathode active material of claim 1 , wherein a thickness of the coating layer is in a range of 10 nm to 1,000 nm.

5. A cathode comprising the cathode active material of claim 1 .

6. A lithium secondary battery comprising the cathode of claim 5 .

7. The cathode active material of claim 1 , wherein the lithium impurities are present in an amount ranging from 0.1 wt % to less than 0.3 wt % based on the total weight of the cathode active material.

Assignees

• Lg Chemical Ltd

Inventors

• Oh Hyun Jin
• Shin Ho Suk
• Lim Jin Hyung
• Lee Dong Hun
• Jin Joo Hong
• Jung Wang Mo

Classifications

• H01M4/1397

  of electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy · 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

• H01M4/366 Primary

  as layered products · CPC title

• H01M10/052

  Li-accumulators · CPC title

• H01M4/505

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