Negative electrode active material, secondary battery, manufacturing method of negative electrode, and processing device of negative electrode

Patent metadata

Field	Value
Publication number	US-2017338470-A1
Application number	US-201515535596-A
Country	US
Kind code	A1
Filing date	Dec 16, 2015
Priority date	Dec 26, 2014
Publication date	Nov 23, 2017
Grant date	—

Abstract

Although a material containing silicon attracts attention as a high-capacity negative electrode active material, it has a problem of having a large irreversible capacity at the initial charge and discharge cycle.
As a negative electrode active material, a particle which is a mixture of silicon, lithium metasilicate, and lithium oxide is used. Because lithium metasilicate and lithium oxide are already contained in the particle of the negative electrode active material, a compound containing lithium and oxygen (lithium orthosilicate and lithium metasilicate), which is a cause of the irreversible capacity at the initial charge, is not generated any more. This enables a negative electrode active material with a small irreversible capacity.

First claim

1 . A negative electrode active material for a lithium-ion secondary battery, the negative electrode active material being a particle including Si, Li 2 SiO 3 , and Li 2 O,
wherein in a 29 Si-NMR spectrum of the particle, an intensity at −78 ppm of the 29 Si-NMR spectrum is higher than or equal to 50 times an intensity at −108 ppm.

2 . A manufacturing method of a negative electrode for a lithium-ion secondary battery, comprising:
a step of applying a particle including silicon over a negative electrode current collector; a step of making the negative electrode current collector over which the particle including silicon is applied and lithium be in contact with an electrolytic solution; and a step of electrically connecting the negative electrode current collector over which the particle including silicon is applied and the lithium and inserting lithium into the particle including silicon at a voltage of higher than or equal to 0.3 V and lower than or equal to 0.6 V on a lithium basis, wherein the negative electrode active material for the lithium-ion secondary battery according to claim 1 is formed after the step of inserting the lithium.

3 . A lithium-ion secondary battery comprising a positive electrode and a negative electrode,
wherein the positive electrode comprises a positive electrode active material, wherein the positive electrode active material comprises a positive electrode active material particle satisfying Li a Mn b Ni c O d (1.6≦a≦1.848, 0.19≦c/b≦0.935, 2.5≦d≦3), wherein the negative electrode comprises a negative electrode active material, wherein the negative electrode active material comprises a negative electrode active material particle including Si, Li 2 SiO 3 , and Li 2 O, and wherein in a 29 Si-NMR spectrum of the negative electrode active material particle, an intensity at −78 ppm of the 29 Si-NMR spectrum is higher than or equal to 50 times an intensity at −108 ppm.

4 . A manufacturing method of a negative electrode for a lithium-ion secondary battery, comprising:
a step of applying a particle including silicon over a negative electrode current collector; a step of making the negative electrode current collector over which the particle including silicon is applied and lithium be in contact with an electrolytic solution; and a step of electrically connecting the negative electrode current collector over which the particle including silicon is applied and the lithium and inserting lithium into the particle including silicon at a voltage of higher than or equal to 0.3 V and lower than or equal to 0.6 V on a lithium basis.

5 . A processing device of a negative electrode, for a lithium-ion secondary battery, comprising:
a terminal capable of being electrically connected to a current collector; lithium; and an electrolytic solution, wherein the terminal and the lithium can be electrically connected to each other; and wherein a voltage higher than or equal to 0.3 V and lower than or equal to 0.6 V on a lithium basis can be applied between the terminal and the lithiu

Assignees

• Semiconductor Energy Lab

Inventors

• Inoue Nobuhiro
• Miyake Hiroyuki
• Sato Yuika

Classifications

• H01M4/5825

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

• H01M4/364 Primary

  as mixtures · CPC title

• H01M4/505

  of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy · CPC title

• H01M4/525

  of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy · CPC title

• H01M4/0459

  Electrochemical doping, intercalation, occlusion or alloying · CPC title