Nonaqueous electrolyte solution and electricity storage device using same

Patent metadata

Field	Value
Publication number	US-9318776-B2
Application number	US-201314422563-A
Country	US
Kind code	B2
Filing date	Aug 21, 2013
Priority date	Aug 24, 2012
Publication date	Apr 19, 2016
Grant date	Apr 19, 2016

Abstract

The present invention provides a nonaqueous electrolytic solution capable of improving electrochemical characteristics at high temperatures and further capable of not only improving a capacity retention rate after a high-temperature cycle test but also decreasing a rate of increase of an electrode thickness, and also to provide an energy storage device using the same. A nonaqueous electrolytic solution having an electrolyte salt dissolved in a nonaqueous solvent, the nonaqueous electrolytic solution containing from 0.001 to 5% by mass of a diisocyanate compound represented by OCN-L-NCO (in the formula, L represents an alkylene group having from 4 to 12 carbon atoms) and further containing from 0.001 to 5% by mass of at least one selected from a specified phosphoric acid ester compound, a specified cyclic sulfonic acid ester compound, a specified isocyanate compound having an ester structure, and a specified triple bond-containing compound, and an energy storage device using the same, are disclosed.

First claim

The invention claimed is:

1. A nonaqueous electrolytic solution having an electrolyte salt dissolved in a nonaqueous solvent, the nonaqueous electrolytic solution comprising from 0.001 to 5% by mass of a diisocyanate compound represented by the following general formula (I) and further comprising from 0.001 to 5% by mass of at least one selected from a phosphoric acid ester compound represented by the following general formula (II), a cyclic sulfonic acid ester compound represented by the following general formula (III), an isocyanate compound having an ester structure and represented by the following general formula (IV), and a triple bond-containing compound represented by the following general formula (V):
OCN-L-NCO  (I)

wherein
L represents an optionally branched alkylene group having from 4 to 12 carbon atoms,

wherein
each of R 1 and R 2 independently represents an alkyl group having from 1 to 6 carbon atoms or a halogenated alkyl group having from 1 to 6 carbon atoms, in which at least one hydrogen atom is substituted with a halogen atom; R 3 represents an alkyl group having from 1 to 6 carbon atoms, an alkenyl group having from 2 to 6 carbon atoms, or an alkynyl group having from 3 to 6 carbon atoms; and each of R 4 and R 5 independently represents a hydrogen atom, a halogen atom, or an alkyl group having from 1 to 4 carbon atoms,

wherein
each of R 6 and R 7 independently represents a hydrogen atom, an alkyl group having from 1 to 6 carbon atoms, in which at least one hydrogen atom may be substituted with a halogen atom, or a halogen atom; X represents —CH(OR 8 )— or —C(═O)—; R 8 represents a formyl group, an alkyl carbonyl group having from 2 to 7 carbon atoms, an alkenyl carbonyl group having from 3 to 7 carbon atoms, an alkynyl carbonyl group having from 3 to 7 carbon atoms, or an aryl carbonyl group having from 7 to 13 carbon atoms; and at least one hydrogen atom in R 8 may be substituted with a halogen atom,

wherein
R 9 represents an alkyl group having from 1 to 6 carbon atoms, an alkenyl group having from 2 to 6 carbon atoms, an aryl group having from 6 to 12 carbon atoms, an alkyloxy group having from 1 to 6 carbon atoms, an alkenyloxy group having from 2 to 6 carbon atoms, an isocyanatoalkyloxy group having from 2 to 6 carbon atoms, or an aryloxy group having from 6 to 12 carbon atoms, in each of which at least one hydrogen atom may be substituted with a halogen atom; and Y represents a linear or branched alkylene group having from 1 to 6 carbon atoms, in which at least one hydrogen atom may be substituted with a halogen atom, or a divalent linking group having from 2 to 6 carbon atoms and containing at least one ether bond, and
Z—O—CH 2 —C≡C—W  (V)

wherein
Z represents R 10 —O—C(═O)—, R 11 —O—C(═O)—C(═O)—, or R 12 —S(═O) 2 —; W represents a hydrogen atom or —CH 2 —O—S(═O) 2 —R 13 ; each of R 10 to R 13 independently represents an alkyl group having from 1 to 6 carbon atoms, an alkenyl group having from 2 to 6 carbon atoms, an alkynyl group having from 2 to 6 carbon atoms, or an aryl group having from 6 to 12 carbon atoms, in each of which at least one hydrogen atom may be substituted with a halogen atom, provided that when Z is R 10 —O—C(═O)— or R 11 —O—C(═O)—C(═O)—, then W is a hydrogen atom.

2. The nonaqueous electrolytic solution according to claim 1 , wherein the diisocyanate compound represented by the general formula (I) is 1,6-diisocyanatohexane.

3. The nonaqueous electrolytic solution according to claim 1 , wherein in the nonaqueous electrolytic solution, the nonaqueous solvent includes a cyclic carbonate and a linear carbonate, and the linear carbonate includes both a symmetric linear carbonate and an asymmetric linear carbonate.

4. The nonaqueous electrolytic solution according to claim 3 , wherein in the nonaqueous electrolytic solution, the cyclic carbonate includes at least two or more selected from ethylene carbonate, propylene carbonate, 1,2-butylene carbonate, 2,3-butylene carbonate, 4-fluoro-1,3-dioxolan-2-one, trans- or cis-4,5-difluoro-1,3-dioxolan-2-one, vinylene carbonate, vinyl ethylene carbonate, and 4-ethynyl-1,3-dioxolan-2-one.

5. The nonaqueous electrolytic solution according to claim 3 , wherein the asymmetric linear carbonate is one or two or more selected from methyl ethyl carbonate, methyl propyl carbonate, methyl isopropyl carbonate, methyl butyl carbonate, and ethyl propyl carbonate.

6. The nonaqueous electrolytic solution according to claim 3 , wherein the symmetric linear carbonate is one or two or more selected from dimethyl carbonate, diethyl carbonate, dipropyl carbonate, and dibutyl carbonate.

7. The nonaqueous electrolytic solution according to claim 1 , wherein the electrolyte salt includes one or two or more lithium salts selected from LiPF 6 , LiBF 4 , LiPO 2 F 2 , Li 2 PO 3 F, LiSO 3 F, LiN(SO 2 F) 2 , LiN(SO 2 CF 3 ) 2 , LiN(SO 2 C 2 F 5 ) 2 , lithium bis[oxalate-O,O′]borate, lithium difluorobis[oxalate-O,O′]phosphate, and lithium tetrafluoro[oxalate-O,O′]phosphate.

8. The nonaqueous electrolytic solution according to claim 7 , wherein a concentration of the lithium salt is from 0.3 to 2.5 M relative to the nonaqueous solvent.

9. An energy storage device comprising a positive electrode, a negative electrode, and a nonaqueous electrolytic solution having an electrolyte salt dissolved in a nonaqueous solvent, wherein the nonaqueous electrolytic solution comprises from 0.001 to 5% by mass of the diisocyanate compound represented by the general formula (I) according to claim 1 and further comprises from 0.001 to 5% by mass of at least one selected from the phosphoric acid ester compound represented by the general formula (II), the cyclic sulfonic acid ester compound represented by the general formula (III), the isocyanate compound having an ester structure and represented by the general formula (IV), and the triple bond-containing compound represented by the general formula (V) according to claim 1 .

10. The energy storage device according to claim 9 , wherein an active material of the positive electrode is a complex metal oxide of lithium containing one or more selected from cobalt, manganese, and nickel, or a lithium-containing olivine-type phosphate containing one or more selected from iron, cobalt, nickel, and manganese.

11. The energy storage device according to claim 9 , wherein an active material of the negative electrode contains one or more selected from a lithium metal, a lithium alloy, a carbon material capable of absorbing and releasing lithium, tin, a tin compound, silicon, a silicon compound, and a lithium titanate compound.

Assignees

• Ube Industries

Inventors

• Abe Koji
• Kondo Masahide

Classifications

• Y02E60/10

  Energy storage using batteries · CPC title

• H01M4/5825

  Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines · CPC title

• H01M10/0567 Primary

  characterised by the additives · CPC title

• H01M10/052

  Li-accumulators · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title