Positive active material for rechargeable lithium battery

Patent metadata

Field	Value
Publication number	US-2018047980-A1
Application number	US-201715789733-A
Country	US
Kind code	A1
Filing date	Oct 20, 2017
Priority date	Dec 12, 2011
Publication date	Feb 15, 2018
Grant date	—

Abstract

Disclosed are a cathode active material for a lithium secondary battery, and a lithium secondary battery including the same. The disclosed cathode active material includes a core including a compound represented by Formula 1; and a shell including a compound represented by Formula 2, in which the core and the shell have different material compositions.

First claim

What is claimed is:

1 . A cathode active material for a lithium secondary battery, comprising:
a core comprising a compound represented by Formula 1; a shell comprising a compound represented by Formula 2; an interlayer between the core and the shell, wherein the core and the shell have different material compositions, wherein
Li x1 M1 y1 M2 z1 PO 4-w1 E w1   [Formula 1]

Li x2 M3 y2 M4 z2 PO 4-w2 E w2   [Formula 2]

in the Formulas 1 and 2, wherein M1 and M3 are the same material, and M2 and M4 are the same materials, and each is independently selected from the group consisting of Ni, Co, Mn, Fe, Na, Mg, Ca, Ti, V, Cr, Cu, Zn, Ge, Sr, Ag, Ba, Zr, Nb, Mo, Al, Ga, B and a combination thereof, E is selected from the group consisting of F, S, and a combination thereof,
0< x 1≦1, 0≦ y 1≦1, 0≦ z 1≦1, and 0< x 1+ y 1+ z 1≦2,

0≦w1≦0.5,

0< x 2≦1, 0≦ y 2≦1, 0≦ z 2≦1, and 0< x 2+ y 2+ z 2≦2,

0≦w2≦0.5, and

x1=x2, y1<y2, and z1>z2,
wherein the interlayer comprises a compound represented by Formula 3 , and
a material of the interlayer is different from the material of the core and the shell,
wherein
Li x3 M5 y3 M6 z3 PO 4-w3 E w3   [Formula 3]

in Formula 3, M5 and M6 are the same or different, and each is independently selected from the group consisting of Ni, Co, Mn, Fe, Na, Mg, Ca, Ti, V, Cr, Cu, Zn, Ge, Sr, Ag, Ba, Zr, Nb, Mo, Al, Ga, B, and a combination thereof, E is selected from the group consisting of F, S, and a combination thereof,
0< x 3≦1, 0≦ y 3≦1, 0≦ z 3≦1, and 0< x 3+ y 3+ z 3≦2, and

0≦w3≦0.5; and

wherein the cathode active material for the lithium secondary battery has a diameter of 5 μm to 15 μm and a tap density of 1 g/cm 3 to 2 g/cm 3 .

2 . The cathode active material for the lithium secondary battery, as claimed in claim 1 , wherein M1 and M3 are selected from the group consisting of Fe, Co, Ni, Mn, and a combination thereof, and M2 and M4 are selected from the group consisting of Mn, Ni, Co, Fe, and a combination thereof.

3 . The cathode active material for the lithium secondary battery, as claimed in claim 1 , wherein the core has a structure in which in a direction away from a center of the core, a concentration of M1 increases, and a concentration of M2 decreases,
M1 is selected from the group consisting of Fe, Co, Ni, Mn, and a combination thereof, and M2 is selected from the group consisting of Mn, Ni, Co, Fe, and a combination thereof

4 . The cathode active material for the lithium secondary battery, as claimed in claim 1 , wherein the core has a diameter of about 5 μm to 20 μm.

5 . The cathode active material for the lithium secondary battery, as claimed in claim 1 , wherein
the shell has a structure in which in a direction away from an interface between the core and the shell, a concentration of M3 increases, and a concentration of M4 decreases, M3 is selected from the group consisting of Fe, Co, Ni, Mn, and a combination thereof, and M4 is selected from the group consisting of Mn, Ni, Co, Fe, and a combination thereof

6 . The cathode active material for the lithium secondary battery, as claimed in claim 1 , wherein the shell has a thickness of about 100 nm to 5 μm.

7 . The cathode active material for the lithium secondary battery, as claimed in claim 1 , further comprising a carbon coating layer on a surface of the shell.

8 . The cathode active material for the lithium secondary battery, as claimed in claim 1 , wherein the carbon coating layer has a thickness of about 10 nm to 200 nm.

9 . The cathode active material for the lithium secondary battery, as claimed in claim 1 , wherein M1, M3, and M5 are the same materials, and M2, M4, and M6 are the same materials, in which x1=x2=x3, y1<y3<y2, and z1>z3>z2.

10 . The cathode active material for the lithium secondary battery, as claimed in claim 1 , wherein M1, M3, and M5 are selected from the group consisting of Fe, Co, Ni, Mn, and a combination thereof, and
M2, M4, and M6 are selected from the group consisting of Mn, Ni, Co, Fe, and a combination thereof.

11 . The cathode active material for the lithium secondary battery, as claimed in claim 1 , wherein M5 is different from M6,
the interlayer has a structure in which in a direction away from the core, a concentration of M5 increases, and a concentration of M6 decreases, M5 is selected from the group consisting of Fe, Co, Ni, Mn, and a combination thereof, and M6 is selected from the group consisting of Mn, Ni, Co, Fe, and a combination thereof

12 . The cathode active material for the lithium secondary battery, as claimed in claim 1 , wherein the interlayer has a thickness of about 100 nm to 24 μm.

13 . A lithium secondary battery comprising:
a cathode comprising a cathode active material; an anode comprising an anode active material; and an electrolyte, wherein the cathode active material is the cathode active material for the lithium secondary battery as claimed in any one of claims 1 - 8 .

Assignees

• Applied Materials Inc
• Industry Univ Cooperation Foundation Hanyang Univ Iucf Hyu

Inventors

• Kwak Byung Sung Leo
• Gordon Ii Joseph G
• Nalamasu Omkaram
• Sun Yangkook
• Kim Wongi
• Oh Seungmin

Classifications

• H01M4/5825

  Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines · CPC title

• C01B25/45

  containing plural metal, or metal and ammonium · CPC title

• H01M4/582

  Halogenides · CPC title

• H01M4/587

  for inserting or intercalating light metals · CPC title

• H01M4/5815

  Sulfides · CPC title