Lithium ion secondary battery

Patent metadata

Field	Value
Publication number	US-10622678-B2
Application number	US-201615736067-A
Country	US
Kind code	B2
Filing date	Jun 23, 2016
Priority date	Jul 15, 2015
Publication date	Apr 14, 2020
Grant date	Apr 14, 2020

Abstract

In terms of a lithium ion secondary battery using, in a positive electrode, a lithium transition metal composite oxide containing an over-stoichiometric amount of lithium, a lithium ion secondary battery in which an amount of a gas generated during charge/discharge cycles is reduced and capacity retention is improved is provided. The lithium ion secondary battery includes a positive electrode containing a lithium transition metal composite oxide containing Fe and containing an over-stoichiometric amount of lithium, and a nonaqueous electrolyte solution, and the nonaqueous electrolyte solution contains a nonaqueous organic solvent, an electrolyte, and lithium difluorophosphate.

First claim

The invention claimed is:

1. A lithium ion secondary battery, comprising: a positive electrode comprising a lithium transition metal composite oxide comprising Fe and comprising an over-stoichiometric amount of lithium; and a nonaqueous electrolyte solution,
wherein the nonaqueous electrolyte solution comprises a nonaqueous organic solvent, an electrolyte, and lithium difluorophosphate,
wherein the lithium transition metal composite oxide comprises at least one compound selected from the group consisting of a compound represented by the following formula (1) and a compound obtained by substituting, by at least one element selected from the group consisting of Co, Sn, Mg, Ti, Al, Zr, Cr, V, Ga, Ge, Zn, Cu, Bi, Mo and La, a part of at least one element selected from the group consisting of Ni, Mn and Fe comprised in the compound:
Li 1+a NiM x Fe z O 2   (1)

wherein 0<a≤0.5, 0<x<1, 0<y<1, and 0<z<1.

2. The lithium ion secondary battery according to claim 1 , wherein the nonaqueous electrolyte solution comprises the lithium difluorophosphate in an amount of 0.005% by mass or more and 10% by mass or less.

3. The lithium ion secondary battery according to claim 1 , wherein the nonaqueous organic solvent comprises a chain carbonate comprising no fluorine, a cyclic carbonate comprising no fluorine, and at least one selected from the group consisting of a fluorinated ether, a fluorinated carbonate and a fluorinated phosphate.

4. The lithium ion secondary battery according to claim 1 , further comprising a negative electrode comprising a material capable of intercalating/deintercalating a lithium ion.

5. The lithium ion secondary battery according to claim 4 , wherein the material capable of intercalating/deintercalating a lithium ion is at least one selected from the group consisting of silicon, a silicon oxide and carbon.

Assignees

• Nec Corp

Inventors

• Maeda Katsumi
• Tamura Noriyuki
• Hattori Sadanori

Classifications

• 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

• H01M2300/0037

  Mixture of solvents · CPC title

• H01M4/505

  of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy · CPC title

• H01M2004/028

  Positive electrodes · CPC title

• H01M10/0569

  characterised by the solvents · CPC title