Cathode active material, method for preparing the same, and lithium secondary batteries including the same

Patent metadata

Field	Value
Publication number	US-9908786-B2
Application number	US-201314084092-A
Country	US
Kind code	B2
Filing date	Nov 19, 2013
Priority date	Nov 22, 2012
Publication date	Mar 6, 2018
Grant date	Mar 6, 2018

Abstract

The present invention relates to a cathode active material for a lithium secondary battery, a method for preparing the same, and a lithium secondary battery including the same. Provided is a cathode active material composed of a lithium-excess lithium metal composite compound including Li 2 MnO 3 having a layered structure, and doped with a fluoro compound, wherein an FWHM (half value width) value is within a range from 0.164 degree to 0.185 degree.

First claim

What is claimed is:

1. A cathode active material comprising:
a lithium-excess lithium metal composite including monoclinic Li 2 MnO 3 having a layered structure and rhombohedral LiMO 2 , wherein M is one or more of Ni, Co, or Mn, and
a fluoro compound,
wherein an FWHM (half value width) value is within a range from 0.164 degree to 0.185 degree,
wherein the lithium-excess lithium metal composite is represented by Formula Li 1+α Ni x Co y Mn z O 2 , wherein 0.1<α≦1 and 0<x+y+z≦1,
wherein the lithium-excess metal composite comprises Li 2 MnO 3 in an amount of 20% or more,
wherein a length of the c-axis in the cathode active material is within a range from 14.241 Å to 14.2429 Å.

2. The cathode active material of claim 1 , wherein the fluoro compound is one selected from the group consisting of LiF, NaF, KF, MgF 2 , CaF 2 , CuF 2 , CdF 2 , FeF 2 , MnF 2 , MgF 2 , NiF 2 , PbF 2 , SnF 2 , SrF 2 , XeF 2 , ZnF 2 , AlF 3 , BF 3 , BiF 3 , CeF 3 , CrF 3 , FeF 3 , InF 3 , LaF 3 , MnF 3 , NdF 3 , VOF 3 , YF 3 , CeF 4 , GeF 4 , HfF 4 , SiF 4 , SnF 4 , TiF 4 , VF 4 , ZrF 4 , VF 5 , NbF 5 , SbF 5 , TaF 5 , BiF 5 , MoF 6 , ReF 6 , SF 6 , WF 6 , NH 4 F, or a mixture thereof.

3. A method for preparing a cathode active material comprising a lithium-excess lithium metal composite including monoclinic Li 2 MnO 3 having a layered structure and rhombohedral LiMO 2 , wherein M is one or more of Ni, Co, or Mn, wherein the lithium-excess lithium metal composite is represented by Formula Li 1+α Ni x Co y Mn z O 2 , wherein 0.1<α≦1 and 0<x+y+z≦1, wherein an FWHM (half value width) value of the cathode active material is within a range from 0.164 degree to 0.185 degree and a length of the c-axis in the cathode active material is within a range from 14.241 Å to 14.2429 Å, the method comprising:
synthesizing a transition metal hydroxide, the transition metal hydroxide being represented by Formula Ni a Co b Mn c (OH) 2 , wherein 0<a<0.4, 0<b≦0.7, 0<c≦0.7, a+b+c=1, and a<b; and
mixing the transition metal hydroxide, a lithium supply source, and a fluoro compound, and then subjecting the mixture to heat treatment at 800° C. or less,
wherein the amount of the fluoro is 0.02 to 0.06 mol per 2.0 mol of a total of the transition metal hydroxide and the lithium supply source.

4. The method of claim 3 , wherein the heat treatment is performed at 700° C.

5. The method of claim 3 , wherein the fluoro is one selected from the group consisting of LiF, NaF, KF, MgF 2 , CaF 2 , CuF 2 , CdF 2 , FeF 2 , MrIF 2 , MgF 2 , NiF 2 , PbF 2 , SnF 2 , SrF 2 , XeF 2 , ZnF 2 , AlF3, BF 3 , BiF 3 , CeF 3 , CrF 3 , FeF 3 , InF 3 , LaF 3 , MnF 3 , NdF 3 , VOF 3 , YF 3 , CeF 4 , GeF 4 , HfF 4 , SiF 4 , SnF 4 , TiF 4 , VF 4 , ZrF 4 , VF s , NbF 5 , SbF 5 , TaF 3 , BiF 5 , MoF 6 , ReF 6 , SF 6 , WF 6 , NH 4 F, or a mixture thereof.

6. The method of claim 3 , wherein the fluoro compound is LiF and the lithium supply source is Li 2 CO 3 .

7. The method of claim 3 , wherein the transition metal hydroxide is synthesized at a pH from 10 to 12.

8. A lithium secondary battery comprising:
a cathode comprising the cathode active material of claim 1 ;
an anode comprising an anode active material; and
an electrolyte present between the cathode and the anode.

Assignees

• Samsung Sdi Co Ltd

Inventors

• Lee Misun
• Moon Jongseok
• Kim Taehyeon
• Choi Shin Jung

Classifications

• H01M10/052

  Li-accumulators · CPC title

• Y02T10/7011

  Cross-Sectional Technologies · mapped topic

• C01D15/02 Primary

  Oxides; Hydroxides · CPC title

• C01P2002/50

  Solid solutions · CPC title

• H01M4/364 Primary

  as mixtures · CPC title