Negative electrode active material, negative electrode, lithium ion secondary battery, method for producing negative electrode material for non-aqueous electrolyte secondary battery and method for producing lithium ion secondary battery
First Claim
1. A negative electrode active material which comprises:
- a negative electrode active material containing particles of negative electrode active material, wherein the particles of negative electrode active material contain a silicon compound represented by SiOx (0.5≤
x≤
1.6), and when the particles of negative electrode active material are measured by an atom probe method and an Si 75% equivalent concentration surface obtained by the atom probe method is defined to be a boundary surface of a silicon grain, an average diameter of the silicon grains at a center portion of the particle in the particles of negative electrode active material is in the range of 0.25 nm to 5 nm, anda ratio A/B of a maximum length A and a minimum length B of the silicon grain is calculated, an average value of the ratio A/B of the silicon grains contained at a surface layer portion of the particle in the particles of negative electrode active material is larger than an average value of the ratio A/B of the silicon grains contained at a center portion of the particle in the particles of negative electrode active material.
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Accused Products
Abstract
A negative electrode active material contains particles of negative electrode active material, wherein the particles of negative electrode active material contain a silicon compound represented by SiOx (0.5≤x≤1.6), and when the particles of negative electrode active material are measured by an atom probe method, and an Si 75% equivalent concentration surface obtained by the atom probe method is defined to be a boundary surface of a silicon grain, an average diameter of the silicon grains at a center portion of the particle in the particles of negative electrode active material is in the range of 0.25 nm to 5 nm. According to this constitution, when it is used as the negative electrode active material of a secondary battery, a negative electrode active material is capable of increasing battery capacity and improving cycle characteristics.
14 Citations
15 Claims
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1. A negative electrode active material which comprises:
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a negative electrode active material containing particles of negative electrode active material, wherein the particles of negative electrode active material contain a silicon compound represented by SiOx (0.5≤
x≤
1.6), and when the particles of negative electrode active material are measured by an atom probe method and an Si 75% equivalent concentration surface obtained by the atom probe method is defined to be a boundary surface of a silicon grain, an average diameter of the silicon grains at a center portion of the particle in the particles of negative electrode active material is in the range of 0.25 nm to 5 nm, anda ratio A/B of a maximum length A and a minimum length B of the silicon grain is calculated, an average value of the ratio A/B of the silicon grains contained at a surface layer portion of the particle in the particles of negative electrode active material is larger than an average value of the ratio A/B of the silicon grains contained at a center portion of the particle in the particles of negative electrode active material. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for producing a negative electrode material for a non-aqueous electrolyte secondary battery containing particles of negative electrode active material, which comprises:
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preparing particles of negative electrode active material containing a silicon compound represented by the general formula;
SiOx (0.5≤
x≤
1.6),measuring the particles of negative electrode active material by an atom probe method, when an Si 75% equivalent concentration surface obtained by the atom probe method is defined to be a boundary surface of a silicon grain, selecting particles of negative electrode active material having an average diameter of the silicon grains at a center portion of the particle in the particles of negative electrode active material of in the range of 0.25 nm to 5 nm and a ratio A/B of a maximum length A and a minimum length B of the silicon grain is calculated, an average value of the ratio A/B of the silicon grains contained at a surface layer portion of the particle in the particles of negative electrode active material is larger than an average value of the ratio A/B of the silicon grains contained at a center portion of the particle in the particles of negative electrode active material, and producing a negative electrode material for a non-aqueous electrolyte secondary battery using the selected particles of negative electrode active material. - View Dependent Claims (14, 15)
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Specification