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US 2023/0406715 A1Published application
Method for producing nano-silicon, negative electrode active material for lithium-ion batteries, negative electrode for lithium-ion batteries, and lithium-ion battery
AssigneeFimatec Ltd.
InventorsMasato KATAYAMA, Tomonao UMEHARA, Kohei YOSHIDA
Life of this patent
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Abstract
A method for producing nano-silicon, involves (a) conducting a reduction treatment on an aluminosilicate, in which a content of Al2O3 is 3 to 40% by mass. A ratio between the number of atoms of aluminum contained in the aluminosilicate and the number of atoms of magnesium used as a reducing agent in the reduction treatment is within a range of 1:3.5 to 1:65. The method then involves (b) conducting acid treatment on a reduced aluminosilicate obtained from (a).
Claims15
1:
- A method for producing nano-silicon, comprising:
- (a) conducting a reduction treatment on an aluminosilicate in which a content of Al2O3 is 3 to 40% by mass, in which a ratio between the number of atoms of aluminum contained in the aluminosilicate and the number of atoms of magnesium used as a reducing agent in the reduction treatment is within a range of 1:3.5 to 1:65;
- and
- (b) conducting an acid treatment on a reduced aluminosilicate obtained in (a).
1 more element
2:
- The production method according to claim 1, wherein the ratio between the numbers of atoms is 1:3.7 to 1:45.
3:
- The production method according to claim 1, wherein the ratio between the numbers of atoms is 1:3.7 to 1:30.
4:
- The production method according to claim 1, wherein the aluminosilicate used in (a) is halloysite or is obtained by conducting a dealumination treatment on halloysite.
5:
- The production method according to claim 1, wherein the aluminosilicate used in (a) is such that the content of Al2O3 is adjusted to 3 to 40% by mass by a dealumination treatment.
6:
- The production method according to claim 5, wherein the dealumination treatment comprises an acid treatment selected from the group consisting of a hot sulfuric acid treatment, a sulfuric acid treatment, a hydrochloric acid treatment, a hot hydrochloric acid treatment, a nitric acid treatment, a hot nitric acid treatment, and a combination thereof.
7:
- The production method according to claim 1, wherein the reduced aluminosilicate obtained in (a) contains 6 to 39% by mass of Al2O3.
8:
- The production method according to claim 1, wherein the reduction treatment in (a) comprises:
- mixing the aluminosilicate with a magnesium powder as the reducing agent and one or more selected from the group consisting of alkali metal chlorides and alkaline earth metal chlorides as an endothermic agent;
- and
- thermally reducing a mixture thus obtained under an argon gas or nitrogen gas atmosphere.
1 more element
9:
- The production method according to claim 1, wherein the acid treatment in (b) uses at least one acid selected from the group consisting of hydrochloric acid, sulfuric acid, and nitric acid.
10:
- The production method according to claim 1, wherein an acid used in (b) is hydrochloric acid, and has a concentration of 0.5 to 2.0 mol/liter.
11:
- A method for producing nano-silicon, comprising:
- obtaining an aluminosilicate in which a content of Al2O3 is 3 to 40% by mass by conducting a hot sulfuric acid treatment on an aluminosilicate, and conducting a reduction treatment on the aluminosilicate thus obtained;
- and
- conducting an acid treatment on a reduced aluminosilicate obtained in the reduction treatment.
1 more element
12:
- A negative electrode active material for lithium-ion batteries, comprising nano-silicon obtained by the production method according to claim 1.
13:
- A negative electrode active material for lithium-ion batteries, comprising nano-silicon in which a halo of amorphous SiO2 which is observed by X-ray diffraction analysis is not present and a peak of spinel which is observed by X-ray diffraction analysis is not present,
- wherein a primary particle diameter of the nano-silicon which is measured by a field emission scanning electron microscope is 10 to 15 nm.
14:
- A negative electrode for lithium-ion batteries, comprising the negative electrode active material according to claim 12.
15:
- A lithium-ion battery, comprising the negative electrode for lithium-ion batteries according to claim 14.