Aqueous electrolyte solution, and aqueous lithium ion secondary battery

Patent metadata

Field	Value
Publication number	US-2019214687-A1
Application number	US-201816229628-A
Country	US
Kind code	A1
Filing date	Dec 21, 2018
Priority date	Jan 9, 2018
Publication date	Jul 11, 2019
Grant date	—

Abstract

Electrolysis of an aqueous electrolyte solution on a surface of an anode is suppressed when an aqueous lithium ion secondary battery is charged/discharged. In an aqueous electrolyte solution that is used for an aqueous lithium ion secondary battery, at least one metal cation selected from an aluminum ion, a titanium ion, a manganese ion, a zinc ion, a gallium ion, a yttrium ion, a zirconium ion, an indium ion, a lanthanum ion, a cerium ion, a neodymium ion, and a hafnium ion is contained so that its content is more than 0 mol and no more than 0.01 mol per kilogram of the aqueous electrolyte solution, in addition to a lithium ion and at least one imide based anion.

First claim

What is claimed is:

1 . An aqueous electrolyte solution that is used for an aqueous lithium ion secondary battery, the aqueous electrolyte solution comprising:
water; a lithium ion; at least one imide based anion selected from a TFSI anion and a FSI anion; and at least one metal cation selected from an aluminum ion, a titanium ion, a manganese ion, a zinc ion, a gallium ion, a yttrium ion, a zirconium ion, an indium ion, a lanthanum ion, a cerium ion, a neodymium ion, and a hafnium ion, wherein pH of the aqueous electrolyte solution is 3 to 12, and a content of the metal cation is more than 0 mol and no more than 0.01 mol per kilogram of the aqueous electrolyte solution.

2 . The aqueous electrolyte solution according to claim 1 , wherein the metal cation is a hafnium ion.

3 . The aqueous electrolyte solution according to claim 1 , wherein the metal cation is at least one selected from a cerium ion, and a neodymium ion, and
the content of the metal cation is no less than 0.0008 mol per kilogram of the aqueous electrolyte solution.

4 . An aqueous lithium ion secondary battery comprising:
a cathode; an anode; and the aqueous electrolyte solution according to claim 1 .

5 . The aqueous lithium ion secondary battery according to claim 4 , wherein
the anode contains at least one titanium-containing oxide selected from lithium titanate and titanium oxide as an anode active material.

6 . The aqueous lithium ion secondary battery according to claim 4 , wherein
the anode includes an anode active material layer including an anode active material and a conductive additive, and the conductive additive is formed of a material of a higher work function than that of a metal forming the metal cation contained in the aqueous electrolyte solution.

7 . The aqueous lithium ion secondary battery according to claim 6 , wherein the conductive additive is formed of a carbon material.

8 . The aqueous lithium ion secondary battery according to claim 4 , wherein
the anode includes an anode current collector, and part of a surface of the anode current collector, the part being in contact with the aqueous electrolyte solution, is formed of a material that is mainly constituted of at least one selected from the group consisting of Al, Ti, Pb, Zn, Sn, Mg, Zr, and In.

Assignees

• Toyota Motor Co Ltd

Inventors

• Suyama Hiroshi

Classifications

• H01M4/485

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

• H01M2300/0002

  Aqueous electrolytes · CPC title

• H01M4/48

  of inorganic oxides or hydroxides · CPC title

• H01M10/36 Primary

  Accumulators not provided for in groups H01M10/05-H01M10/34 · CPC title

• H01M10/38

  Construction or manufacture · CPC title