Positive electrode for lithium-ion secondary battery and lithium-ion secondary battery

Patent metadata

Field	Value
Publication number	US-2017149063-A1
Application number	US-201615299000-A
Country	US
Kind code	A1
Filing date	Oct 20, 2016
Priority date	Nov 19, 2015
Publication date	May 25, 2017
Grant date	—

Abstract

An object of the present invention is to provide a novel positive electrode which is produced using a rubber being an inexpensive material and is capable of enhancing a charge and discharge capacity and cyclability of a lithium-ion secondary battery, and the lithium-ion secondary battery composed of the positive electrode. In the lithium-ion secondary battery, the positive electrode comprises a current collector and an electrode layer formed on a surface of the current collector, the electrode layer comprises an active material, an electrically-conductive additive and a thermosetting resin binder subjected to thermosetting, and the active material comprises a sulfur-based positive-electrode active material prepared by heat-treating a starting material comprising a rubber and sulfur under a non-oxidizing atmosphere.

First claim

What is claimed is:

1 . A positive electrode for a lithium-ion secondary battery comprising a current collector and an electrode layer formed on a surface of the current collector,
wherein the electrode layer comprises an active material, an electrically-conductive additive and a thermosetting resin binder subjected to thermosetting, and the active material comprises a sulfur-based positive-electrode active material prepared by heat-treating a starting material comprising a rubber and sulfur under a non-oxidizing atmosphere.

2 . The positive electrode for a lithium-ion secondary battery of claim 1 , wherein the thermosetting resin binder comprises at least one of a polyimide resin and a polyamide-imide resin.

3 . The positive electrode for a lithium-ion secondary battery of claim 1 , wherein compounding ratios of the active material, the electrically-conductive additive and the thermosetting resin binder in the electrode layer are 30 to 95% by mass, 2 to 40% by mass and 3 to 30% by mass, respectively based on the total compounding amount of the three components.

4 . The positive electrode for a lithium-ion secondary battery of claim 1 , wherein a heat-treating temperature when preparing the sulfur-based positive-electrode active material is from 250° C. to 550° C.

5 . The positive electrode for a lithium-ion secondary battery of claim 1 , wherein the starting material of the sulfur-based positive-electrode active material further comprises a vulcanization accelerator.

6 . The positive electrode for a lithium-ion secondary battery of claim 1 , wherein the starting material of the sulfur-based positive-electrode active material further comprises an electrically-conductive carbon material.

7 . The positive electrode for a lithium-ion secondary battery of claim 6 , wherein the electrically-conductive carbon material is a carbon material having a graphite structure.

8 . The positive electrode for a lithium-ion secondary battery of claim 6 , wherein the starting material of the sulfur-based positive-electrode active material comprises 250 to 1500 parts by mass of the sulfur, 3 to 250 parts by mass of the vulcanization accelerator and 5 to 50 parts by mass of the electrically-conductive carbon material based on 100 parts by mass of the rubber.

9 . The positive electrode for a lithium-ion secondary battery of claim 1 , wherein a total content of the sulfur in the sulfur-based positive-electrode active material is not less than 50% by mass.

10 . A lithium-ion secondary battery comprising the positive electrode for a lithium-ion secondary battery of claim 1 .

Assignees

• Sumitomo Rubber Ind
• Nat Inst Advanced Ind Science & Tech

Inventors

• Kubo Tatsuya
• Yamano Akihiro
• Yamashita Naoto
• Kojima Toshikatsu
• Yanagida Masahiro

Classifications

• H01M4/366

  as layered products · CPC title

• H01M4/382

  Lithium (H01M4/405 takes precedence) · CPC title

• H01M4/625

  Carbon or graphite · CPC title

• H01M4/1393

  of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx · CPC title

• H01M10/0525

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