Lithium secondary battery using ionic liquid
The lithium secondary battery of the present invention is a lithium secondary battery including a positive electrode, a negative electrode, a separator provided between the positive electrode and the negative electrode, and a non-aqueous electrolyte containing a lithium salt, wherein the non-aqueous electrolyte includes, as a solvent, an ionic liquid containing a bis(fluorosulfonyl)imide anion as an anion component; and the separator is a nonwoven fabric comprising at least one member selected from an organic fiber and a glass fiber and has a porosity of 70% or more.
1. A lithium secondary battery comprising:
a positive electrode;
a negative electrode;
a separator provided between said positive electrode and said negative electrode; and
a non-aqueous electrolyte containing a lithium salt, wherein said non-aqueous electrolyte includes, as a solvent, an ionic liquid containing a bis(fluorosulfonyl) imide anion as an anion component and the separator is a nonwoven fabric comprising an organic fiber and a glass fiber and has a porosity of 80% or more and 95% or less, and more than 80% of the mass of the separator comprises said glass fiber and less than 20% of the mass of the separator comprises said organic fiber.
2. The lithium secondary battery according to claim 1 , wherein the separator has an air permeability obtained by the Gurley test method of 200 sec/100 cc or less.
3. The lithium secondary battery according to claim 1 , wherein the separator has the porosity of 85% and 95%.
4. The lithium secondary battery according to claim 3 , wherein the separator is a wet-type sheet which is made in paper-making process and includes one or more glass fibers having a mean fiber diameter of 1 μm or less and less than 20% by mass of an organic component including a fibrillated organic fiber, wherein the glass fibers are bound to each other through entanglement of the fibrillated organic fiber.
5. A lithium secondary battery comprising:
a positive electrode;
a negative electrode;
a separator provided between said positive electrode and said negative electrode; and
a non-aqueous electrolyte, wherein the non-aqueous electrolyte includes, as a solvent, an ionic liquid containing a bis(fluorosulfonyl) imide anion as an anion component and said separator has a porosity of between 85% and 95%, inclusive, and more than 80% of the mass of the separator includes glass fiber and less than 20% of the mass of the separator comprises said organic fiber.
6. A lithium secondary battery comprising:
a positive electrode;
a negative electrode;
a separator provided between said positive electrode and said negative electrode; and
a non-aqueous electrolyte containing a lithium salt, wherein said non-aqueous electrolyte includes, as a solvent, an ionic liquid containing a bis(fluorosulfonyl) imide anion as an anion component and the separator is a nonwoven fabric including at least one member selected from an organic fiber and a glass fiber and has a porosity between 85% and 95%, inclusive, and more than 80% of the mass of the separator includes said glass fiber and less than 20% of the mass of the separator comprises said organic fiber.