Negative electrode active material, method for manufacturing same, and lithium secondary battery

Patent metadata

Field	Value
Publication number	US-9985286-B2
Application number	US-201314442141-A
Country	US
Kind code	B2
Filing date	Oct 28, 2013
Priority date	Nov 13, 2012
Publication date	May 29, 2018
Grant date	May 29, 2018

Abstract

A negative electrode active material comprising silicon oxide satisfying the following Equation 1 and Equation 2 when solid state NMR ( 29 Si-DDMAS) of silicon is measured for the silicon oxide after performing charging at least once is excellent in the performance as a negative electrode active material for a lithium secondary battery;

0.42≤ S 1/( S 1+ S 2+ S 3)≤0.55  (Equation 1)

0.21≤ S 3/( S 1+ S 2+ S 3)≤0.26,  (Equation 2)

in which S1 is a sum of peak areas of a group of signals assigned to Si having a Si—Si bond and having peaks at 0 to −15 ppm, −55 ppm, −84 ppm and −88 ppm, S2 is a sum of peak areas of a group of signals assigned to Si having a Si(OH) 4-n (OSi) n (n=3, 4) structure and having peaks at −100 ppm and −120 ppm, and S3 is a sum of peak areas of a group of signals assigned to Si having a Si(OLi) 4-n (OSi) n (n=0, 1, 2, 3) structure and having peaks at −66 ppm, −74 ppm, −85 ppm and −96 ppm.

First claim

The invention claimed is:

1. An active material for use in a negative electrode comprising silicon oxide which satisfies the following Equation 1 and Equation 2 when solid state NMR ( 29 Si-DDMAS) of silicon is measured for the silicon oxide after performing charging at least once,
0.42≤ S 1/( S 1+ S 2+ S 3)≤0.55  (Equation 1)

0.21≤ S 3/( S 1+ S 2+ S 3)≤0.26,  (Equation 2)

in which S1 is a sum of peak areas of a group of signals assigned to Si having a Si—Si bond and having peaks at 0 to −15 ppm, −55 ppm, −84 ppm and −88 ppm, S2 is a sum of peak areas of a group of signals assigned to Si having a Si(OH) 4-n (OSi) n (n=3, 4) structure and having peaks at −100 ppm and −120 ppm, and S3 is a sum of peak areas of a group of signals assigned to Si having a Si(OLi) 4-n (OSi) n (n=0, 1, 2, 3) structure and having peaks at −66 ppm, −74 ppm, −85 ppm and −96 ppm,
wherein the silicon oxide is pre-doped with lithium first by thermal diffusion and, subsequently, by electrochemical means.

2. The active material according to claim 1 , wherein conditions of the Equation 1 and Equation 2 are satisfied after performing the charging once.

3. A lithium secondary battery comprising a negative electrode comprising an active material according to claim 1 , a binder and a collector, a positive electrode and an electrolyte.

4. A method for manufacturing a negative electrode active material comprising silicon oxide, comprising a step of doping the silicon oxide with lithium,
wherein lithium is doped in the step of doping the silicon oxide with lithium so as to satisfies the following Equation 1 and Equation 2 when solid state NMR ( 29 Si-DDMAS) of silicon is measured for the silicon oxide after performing charging at least once,
0.42< S 1/( S 1+ S 2+ S 3)<0.55  (Equation 1)

0.21< S 3/( S 1+ S 2+ S 3)<0.26,  (Equation 2)

in which S1 is a sum of peak areas of a group of signals assigned to Si having a Si—Si bond and having peaks at 0 to −15 ppm, −55 ppm, −84 ppm and −88 ppm, S2 is a sum of peak areas of a group of signals assigned to Si having a Si(OH) 4-n (OSi) n (n=3, 4) structure and having peaks at −100 ppm and −120 ppm, and S3 is a sum of peak areas of a group of signals assigned to Si having a Si(OLi) 4-n (OSi) n (n=0, 1, 2, 3) structure and having peaks at −66 ppm, −74 ppm, −85 ppm and −96 ppm,
wherein the silicon oxide is doped with lithium by (i) a method utilizing thermal diffusion of lithium and thereafter doped with lithium by (ii) a method of electrochemically doping lithium.

Assignees

• Nec Corp

Inventors

• Iriyama Jiro
• Kawasaki Daisuke
• Fujii Emiko
• Serizawa Shin
• Takahashi Hiroo

Classifications

• H01M4/0459

  Electrochemical doping, intercalation, occlusion or alloying · CPC title

• H01M4/485 Primary

  of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy (H01M4/505, H01M4/525 take precedence) · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M2004/027

  Negative electrodes · CPC title

• H01M4/0445

  Forming after manufacture of the electrode, e.g. first charge, cycling · CPC title