Second battery comprising a phosphate ester compound and a fluorinated carbonate compound

Patent metadata

Field	Value
Publication number	US-9748608-B2
Application number	US-201314382445-A
Country	US
Kind code	B2
Filing date	Feb 4, 2013
Priority date	Mar 2, 2012
Publication date	Aug 29, 2017
Grant date	Aug 29, 2017

Abstract

The present invention relates to a secondary battery, comprising an electrode element comprising a positive electrode and a negative electrode placed opposite to each other, an electrolyte, and an outer package housing the electrode element and the electrolyte; wherein
the negative electrode is formed by binding a negative electrode active material, which comprises a metal (a) capable of being alloyed with lithium, a metal oxide (b) capable of intercalating/deintercalating lithium ions, and a carbon material (c) capable of intercalating/deintercalating lithium ions, to a negative electrode current collector with a negative electrode binder; and the electrolyte comprises a lithium salt dissolved in a solvent comprising 65 vol % or more of a phosphate ester compound, and more than 0 vol % and less than 20 vol % of a fluorinated carbonate compound.

First claim

The invention claimed is:

1. A secondary battery, comprising an electrode element comprising a positive electrode and a negative electrode placed opposite to each other, an electrolyte, and an outer package housing the electrode element and the electrolyte; wherein
the negative electrode is formed by binding a negative electrode active material, which comprises a metal (a) capable of being alloyed with lithium, a metal oxide (b) capable of intercalating/deintercalating lithium ions, and a carbon material (c) capable of intercalating/deintercalating lithium ions, to a negative electrode current collector with a negative electrode binder; and
the electrolyte comprises a lithium salt dissolved in a solvent comprising 65 vol % or more of a phosphate ester compound, and more than 0 vol % and less than 20 vol % of a fluorinated carbonate compound.

2. The secondary battery according to claim 1 , wherein the solvent of the electrolyte comprises 70 to 99 vol % of the phosphate ester compound, and 1 to 15 vol % of the fluorinated carbonate compound.

3. The secondary battery according to claim 1 , wherein the negative electrode active material is mixed with lithium hydride and/or lithium aluminum hydride, and then subjected to heat treatment at a temperature of 200° C. or higher and 800° C. or lower.

4. The secondary battery according to claim 1 , wherein the phosphate ester compound is a compound represented by the following formula (1):

wherein Rs, Rt, and Ru each independently represents alkyl group, halogenated alkyl group, alkenyl group, halogenated alkenyl group, aryl group, cycloalkyl group, halogenated cycloalkyl group, or silyl group; or any two of, or all of Rs, Rt, and Ru are combined to form a cyclic structure.

5. The secondary battery according to claim 4 , wherein each of Rs, Rt, and Ru in the formula (1) is alkyl group having 10 or less carbon atoms.

6. The secondary battery according to claim 1 , wherein the fluorinated carbonate compound is a compound represented by the following formula (2a) or (2b):

wherein Ra, Rb, Rc, Rd, Re, and Rf each independently represents hydrogen atom, alkyl group, halogenated alkyl group, halogen atom, alkenyl group, halogenated alkenyl group, cyano group, amino group, nitro group, alkoxy group, halogenated alkoxy group, cycloalkyl group, halogenated cycloalkyl group, or silyl group; provided that at least one of Ra, Rb, Rc, and Rd is fluorine atom, fluorinated alkyl group, fluorinated alkenyl group, fluorinated alkoxy group, or fluorinated cycloalkyl group, and at least one of Re and Rf is fluorine atom, fluorinated alkyl group, fluorinated alkenyl group, fluorinated alkoxy group, or fluorinated cycloalkyl group; or
a compound represented by the following formula (3):

wherein Ry and Rz each independently represents hydrogen atom, alkyl group, halogenated alkyl group, halogen atom, alkenyl group, halogenated alkenyl group, cyano group, amino group, nitro group, alkoxy group, halogenated alkoxy group, cycloalkyl group, halogenated cycloalkyl group, or silyl group; provided that at least one of Ry and Rz is fluorine atom, fluorinated alkyl group, fluorinated alkenyl group, fluorinated alkoxy group, or fluorinated cycloalkyl group.

7. The secondary battery according to claim 6 , wherein the fluorinated carbonate compound is fluoroethylene carbonate or difluoroethylene carbonate.

8. The secondary battery according to claim 1 , wherein the metal (a) is dispersed in the metal oxide (b).

9. The secondary battery according to claim 1 , wherein the metal oxide (b) has an amorphous structure.

10. The secondary battery according to claim 9 , wherein the carbon material (c) is coating a particle in which the metal (a) is dispersed in the metal oxide (b) having an amorphous structure.

11. The secondary battery according to claim 1 , wherein the metal (a) is silicon, and the oxide (b) is silicon oxide.

12. The secondary battery according to claim 1 , wherein the negative electrode binder consists of polyimide, polyamide-imide, or a mixture of polyimide and polyamide-imide.

13. The secondary battery according to claim 1 , wherein the electrode element has a planar stacked structure.

14. The secondary battery according to claim 1 , wherein the outer package is an aluminum laminate film.

Assignees

• Nec Corp

Inventors

• Kawasaki Daisuke
• Matsumoto Kazuaki

Classifications

• H01M50/105

  Pouches or flexible bags · CPC title

• H01M50/124

  having a layered structure · CPC title

• H01M50/119

  Metals · CPC title

• H01M50/121

  Organic material · CPC title

• H01M10/0569 Primary

  characterised by the solvents · CPC title