Non-aqueous electrolyte and electricity storage device using same
View Patent ↗The present invention provides a nonaqueous electrolytic solution capable of improving electrochemical characteristics in a broad temperature range, such as low-temperature cycle properties and low-temperature discharge properties after high-temperature storage, and provides an energy storage device using the nonaqueous electrolytic solution. The invention includes (1) a nonaqueous electrolytic solution of an electrolyte salt dissolved in a nonaqueous solvent, which comprises from 0.001 to 10% by mass of a compound represented by the following general formula (I), and (2) an energy storage device comprising a positive electrode, a negative electrode, and a nonaqueous electrolytic solution of an electrolyte salt dissolved in a nonaqueous solvent, wherein the nonaqueous electrolytic solution is the nonaqueous electrolytic solution of (1). (In the formula, Y represents a group —C(═O)— or a group —S(═O) 2 —; R 3 and R 4 each independently represent an aryl group having from 6 to 10 carbon atoms in which at least one hydrogen atom is substituted with a halogen atom, or R 3 and R 4 bonding to each other represent a cycloalkanediyl group or a benzenediyl group, having from 5 to 12 carbon atoms. R represents —C(R 1 )(R 2 )— or -L-; R 1 and R 2 each independently represent a hydrogen atom, a halogen atom, or an alkyl group having from 1 to 4 carbon atoms; and L represents a divalent linking group having from 1 to 6 carbon atoms and optionally substituted with a halogen atom).
1. A nonaqueous electrolytic solution of an electrolyte salt dissolved in a nonaqueous solvent, which comprises from 0.001 to 10% by mass of a compound of formula (I):
wherein
Y is a group —C(═O)— or a group —S(═O) 2 —;
R 3 and R 4 bonding to each other are a cycloalkanediyl group having from 5 to 12 carbon atoms or a benzenediyl group, and the cycloalkanediyl group and the benzenediyl group optionally have a substituent;
R is —C(R 1 )(R 2 )— or -L-;
R 1 and R 2 are each independently a hydrogen atom, a halogen atom, or an alkyl group having from 1 to 4 carbon atoms; and
L is a divalent linking group having from 1 to 6 carbon atoms and optionally substituted with a halogen atom.
2. The nonaqueous electrolytic solution according to claim 1 ,
wherein
R is —C(R 1 )(R 2 ).
3. The nonaqueous electrolytic solution according to claim 1 , wherein the nonaqueous solvent comprises a cyclic carbonate and a linear ester.
4. The nonaqueous electrolytic solution according to claim 3 , wherein the cyclic carbonate is at least one selected from the group consisting of 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, and vinylethylene carbonate.
5. The nonaqueous electrolytic solution according to claim 3 , wherein the linear ester is an asymmetric linear carbonate selected from the group consisting of methyl ethyl carbonate, methyl propyl carbonate, methyl isopropyl carbonate, methyl butyl carbonate and ethyl propyl carbonate, a symmetric linear carbonate selected from the group consisting of dimethyl carbonate, diethyl carbonate, dipropyl carbonate and dibutyl carbonate, a linear carboxylate, or any combination thereof.
6. The nonaqueous electrolytic solution according to claim 5 , wherein the linear ester is a methyl group-comprising linear ester selected from the group consisting of methyl ethyl carbonate, methyl propyl carbonate, methyl isopropyl carbonate, methyl butyl carbonate, dimethyl carbonate, methyl propionate, methyl acetate and ethyl acetate.
7. The nonaqueous electrolytic solution according to claim 1 , wherein the electrolyte salt comprises at least one selected from the group consisting of LiPF 6 , LiPO 2 F 2 , Li 2 PO 3 F, LiBF 4 , LiN(SO 2 CF 3 ) 2 , LiN(SO 2 C 2 F 5 ) 2 , LiN(SO 2 F) 2 , lithium difluorobis[oxalate-O,O′]phosphate and lithium tetrafluoro[oxalate-O,O′]phosphate.
8. The nonaqueous electrolytic solution according to claim 1 , wherein a concentration of the electrolyte salt is from 0.3 to 2.5 M relative to the nonaqueous solvent therein.
9. An energy storage device comprising a positive electrode, a negative electrode, and a nonaqueous electrolytic solution of an electrolyte salt dissolved in a nonaqueous solvent, wherein the nonaqueous electrolytic solution is the nonaqueous electrolytic solution of claim 1 .
10. The energy storage device according to claim 9 , wherein the positive electrode active material is a composite metal oxide with lithium that comprises at least one selected from the group consisting of cobalt, manganese and nickel, or a lithium-comprising olivine-type phosphate that comprises at least one selected from the group consisting of iron, cobalt, nickel and manganese.
11. The energy storage device according to claim 9 , wherein the negative electrode active material comprises at least one selected from the group consisting of lithium metal, lithium alloy, and carbon material capable of absorbing and releasing lithium, tin, tin compounds, silicon, silicon compounds, and lithium titanate compounds.