Lithium ion secondary battery
AssigneeNEC Corporation
InventorsTakehiro NOGUCHI, Takuya HASEGAWA, Ikiko SHIMANUKI, Daisuke KAWASAKI
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Abstract
A lithium ion secondary battery having high energy density and being excellent in cycle characteristics is provided. The present invention relates to a lithium ion secondary battery comprising: a negative electrode active material comprising a material comprising silicon as a constituent element; and an electrolyte solution comprising: a non-aqueous solvent comprising a fluorinated ether compound, an open-chain sulfone compound, and a cyclic carbonate compound, and a supporting salt comprising LiPF6, lithium bis(fluorosulfonyl)imide, and lithium bis(oxalato)borate (LiBOB); wherein the content of LiBOB in the electrolyte solution is 0.2 mass % or more.
Claims15
A lithium ion secondary battery comprising:
- (a) a negative electrode active material comprising a material comprising silicon as a constituent element;
- and
- (b) an electrolyte solution comprising:
- (b1) a non-aqueous solvent comprising a fluorinated ether compound represented by the following formula (1), an open-chain sulfone compound represented by the following formula (2), and a cyclic carbonate compound, and
- (b2) a supporting salt comprising LiPF6, lithium bis(fluorosulfonyl)imide (LiFSI), and lithium bis(oxalato)borate (LiBOB);
- wherein
- the content of LiBOB in the electrolyte solution is 0.2 mass % or more;
- R1—O—R2 (1)
- in formula (1), R1 and R2 each independently represent an alkyl group or a fluorinated alkyl group, and at least one of R1 and R2 represents a fluorinated alkyl group;
- in formula (2), R1 and R2 each independently represent a substituted or unsubstituted alkyl group.
A method of producing a lithium ion secondary battery comprising:
- stacking a positive electrode and a negative electrode via a separator to produce an electrode element, and
- enclosing the electrode element and an electrolyte solution in an outer package, wherein
- (a) the negative electrode comprises a negative electrode active material comprising a material comprising silicon as a constituent element, and
- (b) the electrolyte solution comprises:
- (b1) a non-aqueous solvent comprising a fluorinated ether compound represented by the following formula (1), an open-chain sulfone compound represented by the following formula (2), and a cyclic carbonate compound, and
- (b2) a supporting salt comprising LiPF6, lithium bis(fluorosulfonyl)imide (LiFSI), and lithium bis(oxalato)borate (LiBOB) and wherein the content of LiBOB in the electrolyte solution is 0.2 mass % or more;
- R1—O—R2 (1)
- in formula (1), R1 and R2 each independently represent an alkyl group or a fluorinated alkyl group, and at least one of R1 and R2 represents a fluorinated alkyl group;
- in formula (2), R1 and R2 each independently represent a substituted or unsubstituted alkyl group.
(canceled)
Dependencies are inferred from the claim text.