Composite cathode active material, method of preparing the same, and cathode and lithium battery including the composite cathode active material

Patent metadata

Field	Value
Publication number	US-2016181611-A1
Application number	US-201514972216-A
Country	US
Kind code	A1
Filing date	Dec 17, 2015
Priority date	Dec 18, 2014
Publication date	Jun 23, 2016
Grant date	—

Abstract

A composite cathode active material, including a nickel-based lithium transition metal oxide secondary particle, the nickel-based lithium transition metal oxide secondary particle including a coating layer containing lithium and cobalt on a surface of a primary particle of the secondary particle.

First claim

What is claimed is:

1 . A composite cathode active material, comprising a nickel-based lithium transition metal oxide secondary particle, the nickel-based lithium transition metal oxide secondary particle including a coating layer containing lithium and cobalt on a surface of a primary particle of the secondary particle.

2 . The composite cathode active material as claimed in claim 1 , wherein the coating layer further includes another transition metal.

3 . The composite cathode active material as claimed in claim 2 , wherein an amount of cobalt included in the coating layer is greater than about 0 mol % to about 30 mol % or less based on a total amount of the cobalt and the other transition metal.

4 . The composite cathode active material as claimed in claim 1 , wherein a concentration of the cobalt has a concentration gradient that continuously decreases from the coating layer to a center of the primary particle.

5 . The composite cathode active material as claimed in claim 1 , wherein a thickness of the coating layer is about 20 nm or less.

6 . The composite cathode active material as claimed in claim 1 , wherein the coating layer includes:
i) a product obtained by a sol-gel reaction of a composition including a lithium salt and a cobalt salt, or ii) a nickel-based lithium transition metal oxide and a product obtained by a sol-gel reaction of a composition including a lithium salt and a cobalt salt.

7 . The composite cathode active material as claimed in claim 6 , wherein, in the coating layer, an amount of i) the product obtained by a sol-gel reaction of a composition including a lithium salt and a cobalt salt, or ii) the nickel-based lithium transition metal oxide and a product obtained by a sol-gel reaction of a composition including a lithium salt and a cobalt salt, is in a range of about 0.5 parts to about 3 parts by weight based on 100 parts by weight of the composite cathode active material.

8 . The composite cathode active material as claimed in claim 1 , wherein the nickel-based lithium transition metal oxide is a compound represented by Formula 1:
Li a Ni 1-x-y Co x M y O 2+α   [Formula 1]
wherein, in Formula 1, 0.9<a<1.5, 0<x<0.5, 0<y<1, and −0.1≦α≦0.1; and M is one or more of Mg, Ca, Sr, Ba, Ti, Zr, Nb, Mo, W, Zn, Al, Si, Mn, Cr, Fe, V, or a rare earth element.

9 . The composite cathode active material as claimed in claim 1 , wherein the coating layer includes a compound represented by Formula 2:
Li a Ni 1-x-y-z Co x M y Mn z O 2   [Formula 2]
wherein, in Formula 2, M is a transition metal; and 0.9<a<1.5, 0<x≦0.3, 0≦y≦0.1, 0<z≦0.3.

10 . A method of preparing the composite cathode active material as claimed in claim 1 , the method comprising:
performing a sol-gel reaction of a nickel-based lithium transition metal oxide and a composition including a lithium salt and a cobalt salt; and heat-treating a product of the sol-gel reaction in an oxidizing gas atmosphere at a temperature in a range of about 600° C. to about 900° C.

11 . A cathode, comprising the composite cathode active material as claimed in claim 1 .

12 . A lithium battery, comprising the cathode as claimed in claim 11 .

Assignees

• Unist Academy Ind Res Corp
• Samsung Sdi Co Ltd

Inventors

• Cho Kwanghwan
• Cho Jaephil
• Kim Hyejung

Classifications

• H01M2220/20

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

• H01M2220/30

  Batteries in portable systems, e.g. mobile phone, laptop · 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 Primary

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

• Y02E60/10

  Energy storage using batteries · CPC title