Positive electrode for secondary batteries, and secondary battery

Patent metadata

Field	Value
Publication number	US-2020119362-A1
Application number	US-201916713421-A
Country	US
Kind code	A1
Filing date	Dec 13, 2019
Priority date	Jun 20, 2017
Publication date	Apr 16, 2020
Grant date	—

Abstract

This positive electrode is provided with: a positive electrode current collector, a protective layer which is formed on the positive electrode current collector and contains a silicone resin and a conductive material; and a positive electrode mixture layer which is formed on the protective layer and contains a positive electrode active material that is configured from a lithium-containing transition metal oxide.

First claim

1 . A positive electrode for a secondary battery, comprising:
a positive electrode current collector; a protective layer formed on the positive electrode current collector and including a silicone resin and a conductive agent; and a positive electrode mixture layer formed on the protective layer and including a positive electrode active material composed of a lithium-containing transition metal oxide, wherein the silicone resin is an organopolysiloxane represented by a following composition formula (1):
R x SiO (4−x)/2   (1)

wherein, each R independently represents a monovalent hydrocarbon group, hydrogen of the monovalent hydrocarbon group represented by R may be substituted with a halogen atom, and x satisfies 0.1≤x≤2.

2 . The positive electrode for a secondary battery according to claim 1 , wherein R in the composition formula (1) represents a substituent selected from the group consisting of a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a cyclopentyl group, a cyclohexyl group, a phenyl group, a tolyl group, a 2-phenylethyl group, a 2-phenylpropyl group, a 3-phenylpropyl group, a vinyl group, an allyl group, a chloromethyl group, a γ-chloropropyl group and a 3,3,3-trifluoropropyl group.

3 . The positive electrode for a secondary battery according to claim 1 , wherein the organopolysiloxane represented by the composition formula (1) has at least a structural unit including a silicon atom having a phenyl group as a substituent.

4 . The positive electrode for a secondary battery according to claim 3 , wherein a ratio of phenyl groups bonded to silicon atoms based on a total amount of monovalent hydrocarbon groups R bonded to silicon atoms is 10 mol % or more and 80 mol % or less, in the organopolysiloxane represented by the composition formula (1).

5 . The positive electrode for a secondary battery according to claim 1 , wherein the silicone resin contains a hydroxyl group and a hydrolyzable functional group bonded to a silicon atom in a molecule, and wherein a content of the hydroxyl groups and the hydrolyzable functional groups is 3 mass % or less based on a total amount of the silicone resin.

6 . The positive electrode for a secondary battery according to claim 1 , wherein a thickness of the protective layer is 1 μm or more and 10 μm or less.

7 . The positive electrode for a secondary battery according to claim 1 , wherein the protective layer does not contain inorganic compound particles, a content of the silicone resin is 75 mass % or more and 95 mass % or less based on a total amount of the protective layer, and a content of the conductive agent is 5 mass % or more and 25 mass % or less based on a total amount of the protective layer.

8 . The positive electrode for a secondary battery according to claim 1 , wherein the protective layer further includes inorganic compound particles.

9 . The positive electrode for a secondary battery according to claim 8 , wherein based on a total amount of the protective layer, a content of the silicone resin is 15 mass % or more and 55 mass % or less, a content of the conductive agent is 2 mass % or more and 20 mass % or less, and a content of the inorganic compound particles is 40 mass % or more and 75 mass % or less.

10 . A secondary battery, comprising:
the positive electrode for a secondary battery according to claim 1 ; a negative electrode; and an electrolyte.

11 . A positive electrode for a secondary battery, comprising:
a positive electrode current collector; a protective layer formed on the positive electrode current collector and including a silicone resin and a conductive agent; and a positive electrode mixture layer formed on the protective layer and including a positive electrode active material composed of a lithium-containing transition metal oxide, wherein a thickness of the protective layer is 1 μm or more and 10 μm or less.

12 . The positive electrode for a secondary battery according to claim 11 , wherein the silicone resin contains a hydroxyl group and a hydrolyzable functional group bonded to a silicon atom in a molecule, and wherein a content of the hydroxyl groups and the hydrolyzable functional groups is 3 mass % or less based on a total amount of the silicone resin.

13 . The positive electrode for a secondary battery according to claim 11 , wherein the protective layer does not include inorganic compound particles, a content of the silicone resin is 75 mass % or more and 95 mass % or less based on a total amount of the protective layer, and a content of the conductive agent is 5 mass % or more and 25 mass % or less based on a total amount of the protective layer.

14 . The positive electrode for a secondary battery according to claim 11 , wherein the protective layer further includes inorganic compound particles.

15 . The positive electrode for a secondary battery according to claim 14 , wherein based on a total amount of the protective layer, a content of the silicone resin is 15 mass % or more and 55 mass % or less, a content of the conductive agent is 2 mass % or more and 20 mass % or less, and a content of the inorganic compound particles is 40 mass % or more and 75 mass % or less.

16 . A secondary battery, comprising:
The positive electrode for a secondary battery according to claim 11 ; a negative electrode; and an electrolyte.

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Furusawa Daisuke
• Takezawa Hideharu
• Shiozaki Tomoki

Classifications

• H01M2004/028

  Positive electrodes · CPC title

• H01M4/668 Primary

  Composites of electroconductive material and synthetic resins · 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

• H01M4/667 Primary

  in the form of layers, e.g. coatings · CPC title

• H01M10/0525

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