Method for making a sulfur-based positive-electrode active material

Patent metadata

Field	Value
Publication number	US-10847279-B2
Application number	US-201916298575-A
Country	US
Kind code	B2
Filing date	Mar 11, 2019
Priority date	Sep 2, 2015
Publication date	Nov 24, 2020
Grant date	Nov 24, 2020

Abstract

An object of the present invention is to provide a novel sulfur-based positive-electrode active material which can largely improve cyclability of a lithium-ion secondary battery, a positive electrode comprising the positive-electrode active material and a lithium-ion secondary battery comprising the positive electrode. The sulfur-based positive-electrode active material is one comprising: a carbon skeleton derived from a polymer composed of a monomer unit having at least one hetero atom-containing moiety, and sulfur incorporated into the carbon skeleton as the carbon skeleton is formed from the polymer by heat treatment.

First claim

The invention claimed is:

1. A method for making a sulfur-based positive-electrode active material comprising:
a step of providing a polymer composed of a monomer unit comprising at least one hetero atom-containing moiety, and
a step of heat-treating the polymer and sulfur under a non-oxidizing atmosphere at a temperature within a range from 250° C. to 550° C.,
wherein the polymer is at least one selected from the group consisting of polyvinylpyridine, phosphorylcholine polymer, alkylphenol-sulfur chloride condensate and polystyrene sulfonic acid.

2. A method for making a positive-electrode comprising:
producing a positive-electrode according to the method for making the sulfur-based positive-electrode active material of claim 1 .

3. A method for making a lithium-ion secondary battery comprising:
producing a lithium-ion secondary battery according to the method for making the positive electrode of claim 2 .

4. The method for making the sulfur-based positive-electrode active material of claim 1 , wherein the polymer composed of a monomer unit comprising at least one hetero atom-containing moiety is a polyvinylpyridine represented by the following formula (3),

wherein q 1 represents an integer.

5. The method for making the sulfur-based positive-electrode active material of claim 1 , wherein the polymer composed of a monomer unit comprising at least one hetero atom-containing moiety is a phosphorylcholine polymer represented by the following formula (4),

wherein q 2 represents an integer.

6. The method for making the sulfur-based positive-electrode active material of claim 1 , wherein the polymer composed of a monomer unit comprising at least one hetero atom-containing moiety is a alkylphenol-sulfur chloride condensate represented by the following formula (5),

wherein R 3 represents an alkyl group having 5 to 12 carbon atoms, q 3 represents an integer.

7. The method for making the sulfur-based positive-electrode active material of claim 1 , wherein the polymer composed of a monomer unit comprising at least one hetero atom-containing moiety is a polystyrene sulfonic acid represented by the following formula (6),

wherein q 4 represents an integer.

8. The method for making the sulfur-based positive-electrode active material of claim 1 , wherein the polymer is at least one selected from the group consisting of phosphorylcholine polymer and polystyrene sulfonic acid.

9. The method for making the sulfur-based positive-electrode active material of claim 1 , wherein the temperature of the step of heat-treating is from 300° C. to 450° C.

10. The method for making the sulfur-based positive-electrode active material of claim 1 , wherein a weight average molecular weight of the polymer is from 2000 to 1500000.

11. The method for making the sulfur-based positive-electrode active material of claim 1 , wherein during the step of heat-treating, an electrically conductive carbon material is further mixed in addition to the polymer and the sulfur.

12. The method for making the sulfur-based positive-electrode active material of claim 1 , wherein the electrically conductive carbon material is a carbon material comprising a graphite structure.

13. The method for making the sulfur-based positive-electrode active material 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.

Assignees

• Sumitomo Rubber Ind
• Aist

Inventors

• Kubo Tatsuya
• Kojima Toshikatsu
• Sakai Tetsuo
• Yamano Akihiro
• Yanagida Masahiro

Classifications

• H01M4/364 Primary

  as mixtures · CPC title

• H01B1/04 Primary

  mainly consisting of carbon-silicon compounds, carbon or silicon · CPC title

• C01B32/20

  Graphite · CPC title

• H01M4/606

  containing aromatic main chain polymers · CPC title

• H01M2004/028

  Positive electrodes · CPC title