Negative-electrode active material for non-aqueous electrolyte secondary battery, and non-aqueous electrolyte secondary battery

Patent metadata

Field	Value
Publication number	US-10312507-B2
Application number	US-201615524030-A
Country	US
Kind code	B2
Filing date	Jan 18, 2016
Priority date	Jan 28, 2015
Publication date	Jun 4, 2019
Grant date	Jun 4, 2019

Abstract

The initial charge/discharge efficiency and cycle characteristics of a non-aqueous electrolyte secondary battery that contains a silicon material as a negative-electrode active material are improved. A negative-electrode active material particle (10) according to an embodiment includes a lithium silicate phase (11) represented by Li2zSiO(2+z) {0<z<2} and silicon particles (12) dispersed in the lithium silicate phase (11). A lithium silicate constituting the lithium silicate phase has a crystallite size of 40 nm or less. The crystallite size is calculated using the Scherrer equation from the half-width of a diffraction peak of a (111) plane of the lithium silicate in an XRD pattern obtained by XRD measurement of the negative-electrode active material particle 10.

First claim

The invention claimed is:

1. A negative-electrode active material for a non-aqueous electrolyte secondary battery, comprising:
a lithium silicate phase represented by Li 2z ,SiO( 2+z) {0<z <2} and
silicon particles dispersed in the lithium silicate phase,
wherein a lithium silicate constituting the lithium silicate phase has a crystallite size of 40 nm or less when calculated using a Scherrer equation from a half-width of a diffraction peak of a (111) plane of the lithium silicate in an XRD pattern obtained by XRD measurement,
wherein the negative-electrode active material for the non-aqueous electrolyte secondary battery after charging and discharging contains no Li 4 SiO 4 .

2. The negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 1 , wherein the Si (111) plane has a higher diffraction peak intensity than a (111) plane of the lithium silicate in the XRD pattern obtained by XRD measurement.

3. The negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 1 , wherein no diffraction peak of SiO 2 is observed at 2θ=25 degrees in the XRD pattern.

4. The negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 2 , wherein no diffraction peak of SiO 2 is observed at 2θ=25 degrees in the XRD pattern.

5. The negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 1 , wherein the lithium silicate phase is composed mainly of Li 2 Si 2 O 5 , and a diffraction peak of a (111) plane of the Li 2 Si 2 O 5 in the XRD pattern has a half-width of 0.09 degrees or more.

6. The negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 2 , wherein the lithium silicate phase is composed mainly of Li 2 Si 2 O 5 , and a diffraction peak of a (111) plane of the Li 2 Si 2 O 5 in the XRD pattern has a half-width of 0.09 degrees or more.

7. The negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 3 , wherein the lithium silicate phase is composed mainly of Li 2 Si 2 O 5 , and a diffraction peak of a (111) plane of the Li 2 Si 2 O 5 in the XRD pattern has a half-width of 0.09 degrees or more.

8. The negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 4 , wherein the lithium silicate phase is composed mainly of Li 2 Si 2 O 5 , and a diffraction peak of a (111) plane of the Li 2 Si 2 O 5 in the XRD pattern has a half-width of 0.09 degrees or more.

9. The negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 1 , wherein the diffraction peak of the (111) plane of a lithium silicate in the XRD pattern obtained by XRD measurement has a half-width of 0.05 degrees or more.

10. The negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 1 , wherein the lithium silicate phase is composed mainly of Li 2 SiO 3 , and a diffraction peak of a (111) plane of the Li 2 SiO 3 in the XRD pattern has a half-width of 0.10 degrees or more.

11. The negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 1 , wherein the lithium silicate phase and the silicon particles constitute a base particle, and the base particle is covered with an electrically conductive layer.

12. A non-aqueous electrolyte secondary battery comprising: a negative electrode containing the negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 1 ; a positive electrode; and a non-aqueous electrolyte.

13. A non-aqueous electrolyte secondary battery comprising: a negative electrode containing the negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 7 ; a positive electrode; and a non-aqueous electrolyte.

Assignees

• Sanyo Electric Co

Inventors

• Akira Tatsuya
• Kato Yoshio
• Minami Hiroshi
• Sunano Taizou

Classifications

• C01B33/32

  Alkali metal silicates ({C01B33/24} , C01B33/26 take precedence) · CPC title

• H01M4/366

  as layered products · CPC title

• H01M4/364 Primary

  as mixtures · CPC title

• H01M4/5825

  Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines · CPC title

• H01M4/625

  Carbon or graphite · CPC title