Positive active material for nonaqueous electrolyte secondary battery, method for producing positive active material for nonaqueous electrolyte secondary battery, positive electrode for nonaqueous electrolyte secondary battery, nonaqueous electrolyte secondary battery, method for manufacturing nonaqueous electrolyte secondary battery, and method of using nonaqueous electrolyte secondary battery

Patent metadata

Field	Value
Publication number	US-12388116-B2
Application number	US-201917252765-A
Country	US
Kind code	B2
Filing date	Jun 19, 2019
Priority date	Jun 21, 2018
Publication date	Aug 12, 2025
Grant date	Aug 12, 2025

Abstract

A nonaqueous electrolyte secondary battery including a positive electrode, a negative electrode, and a nonaqueous electrolyte, in which the positive electrode includes, as an active material, a lithium-transition metal composite oxide that has an α-NaFeO 2 -type crystal structure, and is represented by the general formula Li 1+α Me 1−α O 2 (0<α, Me is a transition metal element containing Ni and Mn, or containing Ni, Mn, and Co), and has a diffraction peak observed in the range of 20° or more and 22° or less in an X-ray diffraction pattern obtained with a CuKα line.

First claim

The invention claimed is:

1. A positive active material for a nonaqueous electrolyte secondary battery, the positive active material containing a lithium-transition metal composite oxide,
wherein the lithium-transition metal composite oxide has an α-NaFeO 2 -type crystal structure, the lithium-transition metal composite oxide is represented by the general formula Li 1+α Me 1−α O 2 where 0<α, Me is a transition metal element containing Ni and Mn, or containing Ni, Mn, and Co, a molar ratio Mn/Me of Mn to Me meets 0.3≤Mn/Me<0.55, and
a ratio (I 490 /I 600 ) of a maximum value I 490 in a range of 450 cm −1 or more and 520 cm −1 or less to a maximum value I 600 in a range of 550 cm −1 or more and 650 cm −1 or less is 0.45 or more in a Raman spectrum of the lithium-transition metal composite oxide.

2. A method for producing the positive active material of claim 1 , the method comprising adding a sintering aid in a case where a transition metal compound containing Ni and Mn, or containing Ni, Co, and Mn, with the molar ratio Mn/Me of Mn to Me meeting 0.3≤Mn/Me<0.55, is mixed with a Li compound, and fired to produce the lithium-transition metal composite oxide with a molar ratio Li/Me meeting 1<Li/Me.

3. A positive electrode containing the positive active material according to claim 1 .

4. A nonaqueous electrolyte secondary battery comprising the positive electrode according to claim 3 , wherein the positive active material contained in the positive electrode has a diffraction peak observed in a range of 20° or more and 22° or less in an X-ray diffraction pattern obtained with a CuKα line.

5. The positive active material according to claim 1 , wherein the positive active material has a diffraction peak observed in a range of 20° or more and 22° or less in an X-ray diffraction pattern obtained with a CuKα line.

6. The positive active material according to claim 1 , wherein the ratio (I 490 /I 600 ) is 0.45 or more and 0.85 or less in the Raman spectrum of the lithium-transition metal composite oxide.

7. The positive active material according to claim 1 , wherein the molar ratio Mn/Me of Mn to Me meets 0.33≤Mn/Me≤0.50.

8. A nonaqueous electrolyte secondary battery comprising the positive electrode according to claim 3 , wherein
the nonaqueous electrolyte secondary battery has undergone an initial charge-discharge,
a maximum attainable potential of the positive electrode in the initial charge-discharge is less than 4.5 V (vs. Li/Li + ), and
when the positive electrode is charged with electricity to a positive electrode potential of 5.0 V (vs. Li/Li + ), a positive electrode potential change with respect to an amount of charge is relatively flat within a positive electrode potential range of 4.5 V (vs. Li/Li + ) or higher and 5.0 V (vs. Li/Li + ) or lower.

9. A nonaqueous electrolyte secondary battery comprising the positive electrode according to claim 3 , wherein
the nonaqueous electrolyte secondary battery has undergone an initial charge-discharge,
a maximum attainable potential of the positive electrode in the initial charge-discharge is less than 4.5 V (vs. Li/Li + ), and
the positive active material contained in the positive electrode has a diffraction peak observed in a range of 20° or more and 22° or less in an X-ray diffraction pattern obtained with a CuKα line.

10. The positive active material according to claim 1 ,
wherein the molar ratio Mn/Me of Mn to Me meets 0.33≤Mn/Me≤0.50,
the ratio (I 490 /I 600 ) is 0.45 or more and 0.85 or less in the Raman spectrum of the lithium-transition metal composite oxide, and
the positive active material has a diffraction peak observed in a range of 20° or more and 22° or less in an X-ray diffraction pattern obtained with a CuKα line.

11. A positive electrode containing the positive active material according to claim 10 .

12. A nonaqueous electrolyte secondary battery comprising the positive electrode according to claim 11 , wherein
the nonaqueous electrolyte secondary battery has undergone an initial charge-discharge,
a maximum attainable potential of the positive electrode in the initial charge-discharge is less than 4.5 V (vs. Li/Li + ), and
when the positive electrode is charged with electricity to a positive electrode potential of 5.0 V (vs. Li/Li + ), a positive electrode potential change with respect to an amount of charge is relatively flat within a positive electrode potential range of 4.5 V (vs. Li/Li + ) or higher and 5.0 V (vs. Li/Li + ) or lower.

13. A nonaqueous electrolyte secondary battery comprising the positive electrode according to claim 11 , wherein
the nonaqueous electrolyte secondary battery has undergone an initial charge-discharge,
a maximum attainable potential of the positive electrode in the initial charge-discharge is less than 4.5 V (vs. Li/Li + ), and
the positive active material contained in the positive electrode has a diffraction peak observed in a range of 20° or more and 22° or less in an X-ray diffraction pattern obtained with a CuKα line.

14. A nonaqueous electrolyte secondary battery comprising the positive electrode according to claim 3 , wherein when the positive electrode is charged with electricity to a positive electrode potential of 5.0 V (vs. Li/Li + ), a positive electrode potential change with respect to an amount of charge is relatively flat within a positive electrode potential range of 4.5 V (vs. Li/Li + ) or higher and 5.0 V (vs. Li/Li + ) or lower.

15. The nonaqueous electrolyte secondary battery according to claim 4 , for use at a battery voltage at which the positive electrode has a lower maximum attainable potential than 4.5 V (vs. Li/Li + ) in a full charge state (SOC 100%).

16. A method for producing the nonaqueous electrolyte secondary battery according to claim 4 , wherein the positive electrode in an initial charge-discharge step has a lower maximum attainable potential than 4.5 V (vs. Li/Li + ).

17. A method for using the nonaqueous electrolyte secondary battery according to claim 4 , for use at a battery voltage at which the positive electrode has a lower maximum attainable potential than 4.5 V (vs. Li/Li + ) in a full charge state (SOC 100%).

Assignees

• Gs Yuasa Int Ltd

Inventors

• Muramatsu Hiromasa
• Harada Ryo
• Kishimoto Akira

Classifications

• H01M2300/0028

  characterised by the solvent · CPC title

• H01M2004/028

  Positive electrodes · CPC title

• H01M2004/027

  Negative electrodes · CPC title

• H01M10/448

  End of discharge regulating measures · CPC title

• H01M10/446

  Initial charging measures · CPC title