Positive electrode active material and lithium secondary battery comprising the same

Patent metadata

Field	Value
Publication number	US-2022115657-A1
Application number	US-202117355305-A
Country	US
Kind code	A1
Filing date	Jun 23, 2021
Priority date	Oct 12, 2020
Publication date	Apr 14, 2022
Grant date	—

Abstract

The present invention relates to a positive electrode active material having improved electrochemical characteristics and improved stability, and a lithium secondary battery using a positive electrode including the positive electrode active material, and more particularly, to a positive electrode active material which may prevent decreases in electrochemical characteristics and stability of the positive electrode active material, which are caused by Li impurities, in advance by controlling the content of the Li impurities remaining on the surface of the positive electrode active material without a washing process to reduce the amount of residual lithium present on the surface thereof, and a lithium secondary battery using a positive electrode containing the positive electrode active material.

First claim

What is claimed is:

1 . A positive electrode active material, comprising:
a first compound which is represented by Formula 1 below, and enables lithium intercalation/deintercalation; and a second compound represented by Formula 2 below:
Li w Ni 1-(x+y+z) Co x M1 y M2 z O 2+α   [Formula 1]

(Here, M1 is at least one selected from Mn and Al, M2 is at least one selected from Mn, P, Sr, Ba, B, Ti, Zr, Al, Hf, Ta, Mg, V, Zn, Si, Y, Sn, Ge, Nb, W and Cu, M1 and M2 are different elements, 0.5≤w≤1.5, 0≤x≤0.50, 0≤y≤0.20, 0≤z≤0.20, and 0≤α≤0.02), and
Li a Co b M2 c (P β O γ ) d   [Formula 2]

(Here, M3 is at least one selected from Ni, Mn, Fe, Cu, Nb, Mo, Ti, Al, Cr, Zr, Zn, Na, K, Ca, Mg, Pt, Au, B, P, Eu, Sm, W, Ce, V, Ba, Ta, Sn, Hf, Ce, Gd and Nd, 0≤a≤10, 0≤b≤8, 0≤c≤8, 0<d≤13, 0<β≤4, and 0<γ≤10), and wherein the proportion of a compound having a crystal structure belonging to a space group Fd-3m, R3c or R-3m in the second compound is 13 mol % or less.

2 . The positive electrode active material of claim 1 , wherein the compound having a crystal structure belonging to a space group Fd-3m, R3c or R-3m in the second compound has a cubic or rhombohedral crystal structure.

3 . The positive electrode active material of claim 1 , wherein the second compound is contained in a coating layer present at least a part of the surface of the first compound.

4 . The positive electrode active material of claim 1 , wherein the second compound is an oxide comprising at least one first element selected from Group 1A elements, Group 3A elements and Group 5A elements and at least one second element selected from Group 8 elements.

5 . The positive electrode active material of claim 1 , wherein the second compound comprises a first oxide represented by Formula 3 below and a second oxide represented by Formula 4 below:
Li a Co b M3 c (P β O γ ) d   [Formula 3]
(Here, M3 is at least one selected from Ni, Mn, Fe, Cu, Nb, Mo, Ti, Al, Cr, Zr, Zn, Na, K, Ca, Mg, Pt, Au, B, P, Eu, Sm, W, Ce, V, Ba, Ta, Sn, Hf, Ce, Gd and Nd, 0≤a≤10, 0≤b≤8, 0≤c≤8, 0<d≤13, 0<β≤4, and 0<γ≤10), and
Co b″ M3″ c″ (P β″ O γ″ ) d″   [Formula 4]

(Here, M3″ is at least one selected from Ni, Mn, Fe, Cu, Nb, Mo, Ti, Al, Cr, Zr, Zn, Na, K, Ca, Mg, Pt, Au, B, P, Eu, Sm, W, Ce, V, Ba, Ta, Sn, Hf, Ce, Gd and Nd, 0≤b″≤8, 0≤c″≤8, 0<d″≤13, 0≤β″≤4, and 0<γ″≤10).

6 . The positive electrode active material of claim 5 , wherein a ratio (r1/r2) of the proportion r1 of a compound having a crystal structure belonging to space group Fd-3m, R3c or R-3m and the proportion r2 of a compound having a crystal structure belonging to a space group other than Fd-3m, R3c or R-3m among the first oxides is 0.03 or less.

7 . The positive electrode active material of claim 5 , wherein a ratio (s1/s2) of the proportion s1 of a compound having a crystal structure belonging to space group Fd-3m, R3c or R-3m and the proportion s2 of a compound having a crystal structure belonging to a space group other than Fd-3m, R3c or R-3m among the second oxides is 0.24 or less.

8 . The positive electrode active material of claim 1 , wherein the x+y+z of Formula 1 is 0.20 or less.

9 . The positive electrode active material of claim 1 , wherein the first compound contains tungsten in its crystal lattice.

10 . The positive electrode active material of claim 1 , further comprising a third compound represented by Formula 5 below on at least a part of the surface of the first compound:
Li e W f M4 g O h   [Formula 5]
(Here, M4 is at least one selected from Ni, Mn, Co, Fe, Cu, Nb, Mo, Ti, Al, Cr, Zr, Zn, Na, K, Ca, Mg, Pt, Au, B, P, Eu, Sm, Ce, V, Ba, Ta, Sn, Hf, Ce, Gd and Nd, 0≤e≤10, 0<f≤8, 0≤g≤8, and 2≤h≤13).

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

12 . A lithium secondary battery using the positive electrode of claim 11 .

Assignees

• Ecopro Bm Co Ltd

Inventors

• Lee Chang Woo
• Yu Hyun Jong
• Choi Moon Ho

Classifications

• Y02E60/10

  Energy storage using batteries · CPC title

• H01M4/505

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

• H01M2004/028

  Positive electrodes · CPC title

• H01M4/366 Primary

  as layered products · CPC title