Positive electrode active material, and lithium secondary battery using same

Patent metadata

Field	Value
Publication number	US-2016006030-A1
Application number	US-201414761224-A
Country	US
Kind code	A1
Filing date	Jan 22, 2014
Priority date	Jan 24, 2013
Publication date	Jan 7, 2016
Grant date	—

Abstract

A positive electrode active material for lithium secondary batteries disclosed herein comprises a lithium transition metal oxide of a layered structure, represented by formula Li 1+α Ni x Co y Mn z Ca β M γ O 2 (where −0.05≦α≦0.2, x+y+z+β+γ≅1, 0.3≦x≦≦0.7, 0.1≦y≦0.4, 0.1≦z≦0.4, 0.0002≦β≦0.0025, 0.0002≦β+γ≦0.02, and in a case where γ>0, M is absent or represents one, two or more elements selected from the group consisting of Na, Mg, Al, Ti, V, Cr, Zr, Nb, Mo, Hf, Ta and W). The tap density of the positive electrode active material ranges from 1.8 to 2.5 g/cm 3 .

First claim

1 . A particulate positive electrode active material that is used in a lithium secondary battery, comprising:
a lithium transition metal oxide of a layered structure, represented by formula (I)
Li 1+α Ni x Co y Mn z Ca β M γ O 2   (I)

(where, −0.05≦α≦0.2, x+y+z+β+γ=1, 0.0002≦β≦0.0025 and 0.0002≦β+γ≦0.02; and M is absent or represents one, two or more elements selected from the group consisting of Na, Mg, Al, Ti, V, Cr, Zr, Nb, Mo, Hf, Ta and W), wherein the tap density of the positive electrode active material ranges from 1.8 g/cm 3 to 2.5 g/cm 3 .

2 . The positive electrode active material according to claim 1 , wherein
in a volume-basis particle size distribution measured on the basis of a laser diffraction/light scattering method, an average particle size D 50 corresponding to a cumulative 50% from the fine particle side ranges from 5 μm to 9 μm, and a particle size D 10 corresponding to a cumulative 10% from the fine particle side, a particle size D 90 corresponding to a cumulative 90% from the fine particle side, and said average particle size D 50 satisfy the following relationship: (D 90 −D 10 )/D 50 ≦0.7.

3 . The positive electrode active material according to claim 1 , wherein
said positive electrode active material is a hollow structure having a shell section made up of the lithium transition metal oxide of a layered structure, and a hollow section formed inside the shell section, and the thickness of said shell section, on the basis of an electron microscope observation, ranges from 0.1 μm to 2 μm.

4 . The positive electrode active material according to claim 3 , wherein said positive electrode active material has a through-hole that runs through said shell section.

5 . The positive electrode active material according to claim 1 , wherein a crystallite size r of said positive electrode active material, based on X-ray diffraction, ranges from 0.05 μm to 0.2 μm.

6 . A lithium secondary battery in which an electrode assembly including a positive electrode and a negative electrode, and an nonaqueous electrolyte solution, are accommodated inside a battery case, wherein
said battery case has a current interrupt device that is activated when an internal pressure of the battery case rises; and said positive electrode has the positive electrode active material according to claim 1 .

Assignees

• Toyota Motor Co Ltd
• Sumitomo Metal Mining Co

Inventors

• Saka Hideyuki
• Oda Shuhei
• Hayashi Tetsutaro
• Toya Hiroyuki

Classifications

• H01M10/052

  Li-accumulators · 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

• H01M10/4235

  Safety or regulating additives or arrangements in electrodes, separators or electrolyte (H01M10/4242 takes precedence) · CPC title

• H01M4/505 Primary

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

• H01M4/131

  Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title