Amorphous (Lithium) Sulfide or (Lithium) Titanium Niobium Sulfide

Patent metadata

Field	Value
Publication number	US-2016308210-A1
Application number	US-201415026329-A
Country	US
Kind code	A1
Filing date	Sep 17, 2014
Priority date	Oct 4, 2013
Publication date	Oct 20, 2016
Grant date	—

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≦5; 3≦n1≦10; and when n1≧3.5, k1≦1.5, or an amorphous (lithium) titanium niobium sulfide having an average composition represented by formula (2):
Li k2 T 1-m2 Nb m2 S n2
wherein 0≦k2≦5; 0<m2<1; 2≦n2≦10; and when n2≧3.5, k2≦1.5.

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 formula (3):
Li k3 Ti 1-m3 Nb m3 S n3 wherein 0≦k3≦5; 0<m3≦1; 2≦n3≦10; when n3≧3.5, k3≦1.5, the sulfide having an impurity concentration of not more than 2 wt %.

4 . A sulfide comprising the sulfide according to claim 1 as a matrix and 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 having an average composition represented by formula (4):
Li k4 Ti 1-m4 Nb m4 S n4 C x wherein 0≦k4≦5; 0<m4≦1; 2≦n4≦10; 0≦x≦10; when n4≧3.5, k4≦1.5, the 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.

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 , the method using a niobium-containing material and a sulfur-containing material as starting materials or intermediates and comprising subjecting these materials to mechanical milling.

11 . The method according to claim 10 , wherein at least one member selected from the group consisting of crystalline niobium sulfide, amorphous (lithium) niobium sulfide, and amorphous (lithium) titanium niobium sulfide is used as a starting material or intermediate.

12 . The method according to claim 11 , wherein sulfur is further used as a starting material.

13 . The method according to claim 10 , wherein at least one member selected from the group consisting of titanium-containing materials, lithium-containing materials, and carbonaceous materials is further used as a starting 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

• Nat Inst Advanced Ind Science & Tech

Inventors

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

Classifications

• C01P2006/80

  Compositional purity · CPC title

• C01P2002/72

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

• C01G33/006 Primary

  Compounds containing niobium, with or without oxygen or hydrogen, and containing two or more other elements · CPC title

• C01P2002/60

  Compounds characterised by their crystallite size · CPC title

• H01M4/136

  Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy · CPC title