Negative electrode for secondary battery, secondary battery, battery pack, electric vehicle, electric power storage system, electric tool, and electronic device

1. A secondary battery comprising:

a positive electrode;

a negative electrode including a first negative electrode active material, a second negative electrode active material, and a normal temperature molten salt composition; and

an electrolytic solution

wherein the first negative electrode active material includes a first material including carbon, and wherein the second negative electrode active material includes a second material including silicon,

wherein the second negative electrode active material includes:

a center portion including a silicon material; and

a covering portion that is provided on a surface of the center portion and includes at least one of a polyacrylate salt, polyacrylic acid, polyvinylidene fluoride, or polyvinylpyrrolidone, and

wherein the covering portion includes the normal temperature molten salt composition.

2. The secondary battery according to claim 1 , wherein

the normal temperature molten salt composition includes at least one of a normal temperature molten salt or a copolymer of the normal temperature molten salt and a polymer compound,

the normal temperature molten salt includes at least one of a quaternary ammonium cation, a quaternary phosphonium cation, a tertiary sulfonium cation, an imidazolium cation, a pyridinium cation, or a pyrrolidinium cation, and

the polymer compound includes at least one of a polyacrylate salt, polyacrylic acid, polyimide, or polyvinylidene fluoride.

3. The secondary battery according to claim 1 , wherein the normal temperature molten salt includes at least one of a bis(trifluoromethanesulfonyl)imide anion, a bis(fluorosulfonyl)imide anion, a tetrafluoroborate anion, a hexafluorophosphate anion, or a chloride anion.

4. The secondary battery according to claim 1 , wherein the normal temperature molten salt composition includes at least one of an alkoxy group, a hydroxy group, an acryloyl group, or a methacryloyl group.

5. The secondary battery according to claim 1 , wherein the negative electrode further includes a metal salt.

6. The secondary battery according to claim 1 , wherein

the negative electrode further includes a negative electrode binder, and

the negative electrode binder includes at least one of polyvinylidene fluoride, styrene-butadiene rubber, polyimide, a polyacrylate salt, or polyacrylic acid.

7. The secondary battery according to claim 1 , wherein the normal temperature molten salt composition is bonded to the silicon material.

8. The secondary battery according to claim 1 , wherein

the negative electrode further includes a metal salt, and

the covering portion includes the metal salt.

9. The secondary battery according to claim 1 , wherein

the negative electrode further includes a negative electrode binder,

the negative electrode binder includes at least one of polyvinylidene fluoride, styrene-butadiene rubber, polyimide, a polyacrylate salt, or polyacrylic acid, and

the normal temperature molten salt composition is bonded to the negative electrode binder.

10. The secondary battery according to claim 1 , wherein the secondary battery includes a lithium ion secondary battery.

11. An electric vehicle comprising:

the secondary battery according to claim 1 ;

a converter configured to convert electric power supplied from the secondary battery into a driving force;

a driver configured to be driven in accordance with the driving force; and

a controller configured to control operation of the secondary battery.

12. An electric power storage system comprising:

the secondary battery according to claim 1 ;

one or two or more electrical apparatuses to which electric power is configured to be supplied from the secondary battery; and

a controller configured to control electric power supply from the secondary battery to the electrical apparatuses.

13. An electric tool comprising:

the secondary battery according to claim 1 ; and

a moving unit to which electric power is configured to be supplied from the secondary battery.

14. An electronic device comprising:

the secondary battery according to claim 1 as an electric power supply source.

15. A negative electrode for secondary battery comprising:

a first negative electrode active material including a first material including carbon;

a second negative electrode active material including a second material including silicon; and

a normal temperature molten salt composition,

wherein the second negative electrode active material includes:

a center portion including a silicon material; and

a covering portion that is provided on a surface of the center portion and includes at least one of a polyacrylate salt, polyacrylic acid, polyvinylidene fluoride, or polyvinylpyrrolidone, and

wherein the covering portion includes the normal temperature molten salt composition.

16. A battery pack comprising:

a secondary battery;

a controller configured to control operation of the secondary battery; and

a switch configured to switch operation of the secondary battery in accordance with an instruction from the controller,

wherein

the secondary battery includes

a positive electrode;

a negative electrode including a first negative electrode active material, a second negative electrode active material, and a normal temperature molten salt composition; and

an electrolytic solution,

wherein the first negative electrode active material includes a first material including carbon, and wherein the second negative electrode active material includes a second material including silicon,

wherein the second negative electrode active material includes:

a center portion including a silicon material; and

a covering portion that is provided on a surface of the center portion and includes at least one of a polyacrylate salt, polyacrylic acid, polyvinylidene fluoride, or polyvinylpyrrolidone, and

wherein the covering portion includes the normal temperature molten salt composition.