Positive active material, manufacturing method thereof, and positive electrode and lithium battery including the positive active material

Patent metadata

Field	Value
Publication number	US-2016336594-A1
Application number	US-201615153867-A
Country	US
Kind code	A1
Filing date	May 13, 2016
Priority date	May 15, 2015
Publication date	Nov 17, 2016
Grant date	—

Abstract

A positive active material includes an over-lithiated lithium transition metal oxide having a core-shell structure, wherein a shell layer of the core-shell structure includes a metal cation.

First claim

What is claimed is:

1 . A positive active material comprising an over-lithiated lithium transition metal oxide having a core-shell structure,
wherein a shell layer of the core-shell structure comprises a metal cation.

2 . The positive active material of claim 1 , wherein a core of the core-shell structure does not comprise the metal cation.

3 . The positive active material of claim 1 , wherein the metal cation is at least one metal cation selected from elements of Period 2 to Period 7 of the Periodic Table of the Elements.

4 . The positive active material of claim 1 , wherein the metal cation is at least one metal cation selected from V, Al, Mg, Ca, Sc, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Sr, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, and In.

5 . The positive active material of claim 1 , wherein an amount of the metal cation is in a range of about 0.1 mole percent to about 10 mole percent, based on 1 mole of the over-lithiated lithium transition metal oxide.

6 . The positive active material of claim 1 , wherein a thickness of the shell layer of the core-shell structure is in a range of about 0.1 nanometers to about 500 nanometers.

7 . The positive active material of claim 1 , wherein the over-lithiated lithium transition metal oxide is represented by Formula 1:
x Li 2 MO 3 -(1 −x )LiM′O 2   Formula 1

wherein in Formula 1,
M has an average oxidation number of +4 and is at least one element selected from Period 2 to Period 5 of the Periodic Table of the Elements,
M′ has an average oxidation number of +3 and is at least one element selected from Period 2 to Period 5 of the Periodic Table of the Elements, and
0<x<1.

8 . The positive active material of claim 7 , wherein M in Formula 1 is at least one metal selected from Mn, Ti, Zr, Sn, and Mo, and
wherein M′ in Formula 1 is at least one metal selected from Ni, Co, Mn, Fe, Al, Mg, Zn, Cu, Cr, V, and Nb.

9 . The positive active material of claim 1 , wherein the over-lithiated lithium transition metal oxide is represented by Formula 2:
x Li 2 MnO 3 -(1 −x )LiNi a Co b Mn c O 2   Formula 2

wherein in Formula 2,
0<x<1, 0<a<1, 0<b<1, 0<c<1, and a+b+c=1.

10 . The positive active material of claim 1 , wherein the over-lithiated lithium transition metal oxide is represented by Formula 3:
Li[Li a Ni b CO c Mn d M f ]O 2-x F x   Formula 3

wherein in Formula 3,
M is at least one metal selected from Ti, V, Al, Mg, Cr, Fe, Zr, Re, Al, B, Ge, Ru, Sn, Nb, Mo, and Pt, and
a+b+c+d+f=1, 0<a<1, 0<b<1, 0<c<1, 0<d<1, 0≦f<1, and 0<x<0.1.

11 . The positive active material of claim 10 , wherein M in Formula 3 is at least one metal selected from Ti, V, Al, Mg, Cr, Fe, and Zr.

12 . The positive active material of claim 9 , wherein in Formula 3, 0.1<a<0.25, 0.1<b<0.4, 0<c<0.2, and f=0, and d satisfies 0.8<(2a+b)/d<1.2.

13 . The positive active material of claim 6 , wherein at least one of the Li 2 MO 3 phase and the LiM′O 2 phase included in the shell layer of the core-shell structure comprises the metal cation.

14 . The positive active material of claim 1 , wherein the metal cation has a concentration gradient that gradually decreases in a direction from an outer surface of the shell layer to an inner surface of the shell layer.

15 . The positive active material of claim 1 , wherein the over-lithiated lithium transition metal oxide is a particle having an average particle diameter of about 10 nanometers to about 500 micrometers.

16 . A positive electrode comprising the positive active material of claim 1 .

17 . A lithium battery comprising the positive electrode of claim 16 .

18 . A method of manufacturing a positive active material, the method comprising:
contacting a transition metal precursor and a metal cation precursor to form a coating comprising a metal cation on the transition metal precursor; combining the metal cation coated transition metal precursor with a Li source to form a mixture; and heat treating the mixture to obtain the positive active material, wherein the positive active material comprises an over-lithiated lithium transition metal oxide having a core-shell structure, wherein a shell layer of the core-shell structure comprises the metal cation.

19 . The method of claim 18 , wherein the contacting of the transition metal precursor and the metal cation precursor comprises dispersing the transition metal precursor and the metal cation precursor in a solvent.

20 . The method of claim 18 , further comprising adding a fluorine compound during the heat treatment.

21 . The method of claim 20 , wherein the fluorine compound is at least one selected from lithium fluoride, magnesium fluoride, strontium fluoride, beryllium fluoride, calcium fluoride, ammonium fluoride, ammonium difluoride, and ammonium hexafluoroaluminate.

22 . The method of claim 18 , wherein the heat treating is performed at a temperature of about 700° C. to about 900° C.

Assignees

• Samsung Electronics Co Ltd
• Samsung Sdi Co Ltd

Inventors

• Ahn Sungjin
• Park Jinhwan
• Song Jayhyok
• Kapylou Andrei
• Yu Byongyong

Classifications

• H01M4/62

  Selection of inactive substances as ingredients for active masses, e.g. binders, fillers · CPC title

• H01M4/366 Primary

  as layered products · CPC title

• C01G53/50

  of the type (MnO2)n-, e.g. Li(NixMn1-x)O2 or Li(MyNixMn1-x-y)O2 · 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

• C01P2004/03

  obtained by SEM · CPC title