Amorphous (lithium) niobium sulfide or (lithium) titanium niobium sulfide

Patent metadata

Field	Value
Publication number	US-10269465-B2
Application number	US-201415026329-A
Country	US
Kind code	B2
Filing date	Sep 17, 2014
Priority date	Oct 4, 2013
Publication date	Apr 23, 2019
Grant date	Apr 23, 2019

Abstract

The sulfide of the present invention comprises an amorphous (lithium) niobium sulfide having an average composition represented by formula (1): Li k1 NbS n1 (wherein 0≤k1≤5; 3≤n1≤10; and when n1≥3.5, k1≤0.5), or an amorphous (lithium) titanium niobium sulfide having an average composition represented by formula (2): Li k2 Ti 1-m2 Nb m2 S n2 (wherein 0≤k2≤5; 0<m2<1; 2≤n2≤10; and when n2≥3.5, k2≤1.5). The sulfide of the present invention is a material that is useful as a cathode active material for lithium batteries, such as lithium primary batteries, lithium secondary batteries, and lithium ion secondary batteries, and has a high charge-discharge capacity, high electrical conductivity, and excellent charge-discharge performance.

First claim

We claim:

1. A sulfide comprising an amorphous (lithium) niobium sulfide having an average composition represented by formula (1):
Li k1 NbS n1
wherein 0≤k1≤1.5; 3.5≤n1≤10, or
an amorphous (lithium) titanium niobium sulfide having an average composition represented by formula (2):
Li k2 Ti 1-m2 Nb m2 S n2

wherein the formula (2) satisfies (i) or (ii) below,
(i) 0≤k2≤5; 0<m2<1; and 3≤n2≤3.5, or
(ii) 0□k2□□□5; 0<m2<1; and 3.5□n2□10.

2. The sulfide according to claim 1 , wherein the sulfide has an impurity concentration of not more than 2 wt. %.

3. A sulfide comprising an amorphous sulfide having an average composition represented by a formula:
Li k3 Ti 1-m3 Nb m3 S n3
wherein 0≤k3≤1.5; 0<m3≤1; 3.5≤n3≤10,
the sulfide having an impurity concentration of not more than 2 wt. %.

4. The sulfide according to claim 1 , wherein the amorphous (lithium) niobium sulfide or the amorphous (lithium) titanium niobium sulfide is present as a matrix, and the sulfide further comprises a crystalline metal sulfide that is present in the matrix.

5. The sulfide according to claim 1 , wherein in an X-ray diffraction diagram obtained using CuKα radiation, the sulfide has a half-width of 0.3° or more at diffraction angles 2θ=15.0±0.5°, 15.5±0.5°, and 23.0±0.5°, or has no diffraction peaks at diffraction angles 2θ=15.0±0.5°, 15.5±0.5°, and 23.0±0.5°.

6. The sulfide according to claim 1 , wherein the sulfide contains no crystallites, or has an average crystallite size of 5 nm or less.

7. A sulfide comprising:
an amorphous (lithium) niobium sulfide or an amorphous (lithium) titanium niobium sulfide as a matrix; and
a crystalline metal sulfide or carbon that is present in the matrix,
wherein the sulfide has an average composition represented by a formula:
Li k4 Ti 1-m4 Nb m4 S n4 C x

wherein 0≤k4≤1.5; 0<m4≤1; 3.5n4≤10; 0≤x≤10.

8. The sulfide according to claim 7 , wherein in an X-ray diffraction diagram obtained using CuKα radiation, the amorphous (lithium) niobium sulfide or amorphous (lithium) titanium niobium sulfide has a half-width of 0.3° or more at diffraction angles 2θ=15.0±0.5°, 15.5±0.5°, and 23.0±0.5°, or has no diffraction peaks at diffraction angles 2θ=15.0±0.5°, 15.5±0.5°, and 23.0±0.5°.

9. The sulfide according to claim 7 , wherein the amorphous (lithium) niobium sulfide or amorphous (lithium) titanium niobium sulfide contains no crystallites, or has an average crystallite size of 5 nm or less.

10. A method for producing the sulfide according to claim 1 comprising mechanically milling a starting material, wherein the starting material comprises a niobium-containing material and a sulfur-containing material.

11. The method according to claim 10 , wherein the starting material comprises at least one of crystalline niobium sulfide, amorphous (lithium) niobium sulfide, and amorphous (lithium) titanium niobium sulfide.

12. The method according to claim 11 , wherein the starting material further comprises sulfur.

13. The method according to claim 10 , wherein the starting material further comprises at least one of a titanium-containing material, a lithium-containing material, and a carbonaceous material.

14. The method according to claim 13 , wherein the titanium-containing material is titanium sulfide, and the lithium-containing material is lithium sulfide.

15. A charge-discharge product of the sulfide according to claim 1 .

16. A cathode active material for lithium batteries comprising the sulfide according to claim 1 .

17. An electrode for lithium batteries comprising the cathode active material for lithium batteries according to claim 16 .

18. The electrode for lithium batteries according to claim 17 , wherein the electrode is a cathode for lithium batteries.

19. A lithium battery comprising the electrode for lithium batteries according to claim 17 .

20. The lithium battery according to claim 19 , wherein the lithium battery is a non-aqueous electrolyte battery or an all-solid-state battery.

Assignees

• Aist

Inventors

• Sakuda Atsushi
• Takeuchi Tomonari
• Taguchi Noboru
• Sakaebe Hikari
• Tatsumi Kuniaki

Classifications

• C01P2002/60

  Compounds characterised by their crystallite size · CPC title

• H01B1/10 Primary

  sulfides · CPC title

• C01P2002/72

  by d-values or two theta-values, e.g. as X-ray diagram · CPC title

• H01M10/052

  Li-accumulators · CPC title

• C01P2006/40

  Electric properties · CPC title