Non-aqueous electrolytic solution for lithium secondary battery or lithium ion capacitor, and lithium secondary battery or lithium ion capacitor using the same

Patent metadata

Field	Value
Publication number	US-2018277900-A1
Application number	US-201615765068-A
Country	US
Kind code	A1
Filing date	Sep 29, 2016
Priority date	Oct 1, 2015
Publication date	Sep 27, 2018
Grant date	—

Abstract

The present invention provides a non-aqueous electrolytic solution for a lithium secondary battery or a lithium ion capacitor, wherein the non-aqueous electrolytic solution includes a lithium salt as dissolved in a non-aqueous solvent in a concentration of 0.8 to 1.5 M (mol/L), the non-aqueous solvent includes, in relation to the whole of the non-aqueous solvent, 5 to 25% by volume of ethylene carbonate, 5 to 25% by volume of propylene carbonate, 20 to 30% by volume of dimethyl carbonate, 20 to 40% by volume of methyl ethyl carbonate, and 10 to 20% by volume of a fluorinated chain ester; the total content of ethylene carbonate and propylene carbonate in the non-aqueous solvent is 20 to 30% by volume, the total content of dimethyl carbonate and the fluorinated chain ester in the non-aqueous solvent is 30 to 40% by volume; and the flash point of the non-aqueous electrolytic solution is 20° C. or higher, and the present invention also provides an energy storage device.

First claim

1 . A non-aqueous electrolytic solution, comprising:
a non-aqueous solvent; and a lithium salt dissolved in the non-aqueous solvent in a concentration of 0.8 to 1.5 M (mol/L), wherein the non-aqueous solvent comprises, based on a whole of the non-aqueous solvent, 5 to 25% by volume of ethylene carbonate, 5 to 25% by volume of propylene carbonate, 20 to 30% by volume of dimethyl carbonate, 20 to 40% by volume of methyl ethyl carbonate, and 10 to 20% by volume of a fluorinated chain ester, in the non-aqueous solvent, a total amount of ethylene carbonate and propylene carbonate is 20 to 30% by volume, and a total amount of dimethyl carbonate and the fluorinated chain ester is 30 to 40% by volume, and a flash point of the non-aqueous electrolytic solution is 20° C. or higher.

2 . A non-aqueous electrolytic solution, comprising:
a non-aqueous solvent; and a lithium salt dissolved in the non-aqueous solvent in a concentration of 0.9 to 1.5 M (mol/L), wherein the non-aqueous solvent comprises, based on a whole of the non-aqueous solvent, 5 to 25% by volume of ethylene carbonate, 5 to 25% by volume of propylene carbonate, 20 to 30% by volume of dimethyl carbonate, 20 to 40% by volume of methyl ethyl carbonate, and 10 to 20% by volume of ethyl propionate, a total amount of ethylene carbonate and propylene carbonate in the non-aqueous solvent is 20 to 30% by volume, and a total amount of dimethyl carbonate and ethyl propionate in the non-aqueous solvent is 30 to 40% by volume, and a flash point of the non-aqueous electrolytic solution is 20° C. or higher.

3 . The non-aqueous electrolytic solution of claim 1 , wherein the fluorinated chain ester is at least one selected from the group consisting of 2,2-difluoroethyl acetate (DFEA), 2,2,2-trifluoroethyl acetate (TFEA), 2,2-difluoroethyl methyl carbonate (DFEMC), 2,2,2-trifluoroethyl methyl carbonate (TFEMC), methyl trifluoroacetate, ethyl trifluoroacetate, 2,2-difluoroethyl trifluoroacetate, and 2,2,2-trifluoroethyl trifluoroacetate.

4 . The non-aqueous electrolytic solution of claim 1 , wherein a freezing point of the non-aqueous electrolytic solution is −45° C. or lower.

5 . The non-aqueous electrolytic solution of claim 1 , further comprising vinylene carbonate in an amount of 0.1 to 5% by volume based on the whole of the non-aqueous solvent.

6 . The non-aqueous electrolytic solution of claim 1 , further comprising fluoroethylene carbonate in an amount of 1 to 10% by volume based on the whole of the non-aqueous solvent.

7 . The non-aqueous electrolytic solution of claim 1 , wherein the lithium salt comprises at least one selected from the group consisting of LiPF 6 , (FSO 2 ) 2 NLi, LiPO 2 F 2 , lithium methyl sulfate, lithium ethyl sulfate, FSO 3 Li, lithium difluoro(oxalato)borate, lithium tetrafluoro(oxalato)phosphate, lithium difluorobis(oxalato)phosphate, and lithium bis(oxalato)borate.

8 . A lithium secondary battery, comprising:
a positive electrode; a negative electrode; and the non-aqueous electrolytic solution of claim 1 .

9 . The lithium secondary battery of claim 8 , wherein the positive electrode comprises, as a positive electrode active material, at least one selected from the group consisting of a lithium composite metal oxide and a lithium-containing olivine-type phosphate.

10 . The lithium secondary battery of claim 8 , wherein the negative electrode comprises, as a negative electrode active material, at least one selected from the group consisting of lithium metal, a lithium alloy, a carbon material capable of occluding and releasing lithium, tin (elementary substance), a tin compound, silicon (elementary substance), a silicon compound, and a lithium titanate compound.

11 . A lithium ion capacitor, comprising:
a positive electrode; a negative electrode; and the non-aqueous electrolytic solution of claim 1 .

12 . The lithium ion capacitor of claim 11 , wherein the positive electrode comprises, as a positive electrode active material, an activated carbon.

13 . The lithium ion capacitor according to claim 11 , wherein the negative electrode comprises, as a negative electrode active material, at least one selected from the group consisting of lithium metal, a lithium alloy, a carbon material capable of occluding and releasing lithium, tin (elementary substance), a tin compound, silicon (elementary substance), a silicon compound, and a lithium titanate compound.

Assignees

• Ube Industries

Inventors

• Abe Koji
• Babazono Makoto
• Kondo Masahide
• Yanagi Hiroshi
• Shimamoto Kei

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

• H01M2300/0042

  Four or more solvents · CPC title

• H01M4/587

  for inserting or intercalating light metals · CPC title

• H01G11/32

  Carbon-based · CPC title

• H01G11/50

  specially adapted for lithium-ion capacitors, e.g. for lithium-doping or for intercalation · CPC title