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

Patent metadata

Field	Value
Publication number	US-2017331102-A1
Application number	US-201615524030-A
Country	US
Kind code	A1
Filing date	Jan 18, 2016
Priority date	Jan 28, 2015
Publication date	Nov 16, 2017
Grant date	—

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 Li 2z SiO (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

1 - 9 . (canceled)

10 . 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 a non-aqueous electrolyte secondary battery after charging and discharging contains no Li 4 SiO 4 .

11 . The negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 10 , wherein the Si (111) plane has a higher diffraction peak intensity than a (111) plane of a lithium silicate in the XRD pattern obtained by XRD measurement.

12 . The negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 10 , wherein no diffraction peak of SiO 2 is observed at 2θ=25 degrees in the XRD pattern.

13 . The negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 11 , wherein no diffraction peak of SiO 2 is observed at 2θ=25 degrees in the XRD pattern.

14 . The negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 10 , 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.

15 . The negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 11 , 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.

16 . The negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 12 , 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.

17 . The negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 13 , 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.

18 . The negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 10 , wherein the diffraction peak of a (111) plane of a lithium silicate in the XRD pattern obtained by XRD measurement has a half-width of 0.05 degrees or more.

19 . The negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 10 , 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.

20 . The negative-electrode active material for a non-aqueous electrolyte secondary battery according to claim 10 , wherein the lithium silicate phase and the silicon particles constitute a base particle, and the base particle is covered with an electrically conductive layer.

21 . 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 10 ; a positive electrode; and a non-aqueous electrolyte.

22 . 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 16 ; a positive electrode; and a non-aqueous electrolyte.

Assignees

• Sanyo Electric Co

Inventors

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

Classifications

• H01M4/386

  Silicon or alloys based on silicon · CPC title

• C01B33/32

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

• H01M2004/027

  Negative electrodes · CPC title

• H01M4/5825

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

• H01M4/366

  as layered products · CPC title