Electrode, power storage device, and electronic device
A power storage device with high capacity or high energy density is provided. A highly reliable power storage device is provided. A long-life power storage device is provided. An electrode includes an active material, a first binder, and a second binder. The specific surface area of the active material is S [m 2 /g]. The weight of the active material, the weight of the first binder, and the weight of the second binder are a, b, and c, respectively. The solution of {(b+c)/(a+b+c)}×100÷S is 0.3 or more. The electrode includes a first film in contact with the active material. The first film preferably includes a region in contact with the active material. The first film preferably includes a region with a thickness of 2 nm or more and 20 nm or less. The first film contains a water-soluble polymer.
1. An electrode comprising:
an active material comprising an active material particle;
a first film covering the active material particle, the first film comprising a first binder and a second binder;
a second film covering the active material particle and the first film, the second film comprising Li, F, O and C,
wherein a first portion of the second film is in contact with the first film,
wherein a second portion of the second film is in contact with the active material particle,
wherein the first binder is a water-soluble polymer,
wherein a thickness of the first portion of the second film is thinner than a thickness of the second portion of the second film.
2. The electrode according to claim 1 , wherein the second binder comprises a double bond which is capable of reacting with osmium tetroxide.
3. The electrode according to claim 1 , wherein a repeating unit of the second binder comprises a stylene monomer unit.
4. The electrode according to claim 3 , wherein the second binder further comprises a butadiene monomer unit.
5. The electrode according to claim 1 , wherein a material of the active material particle is graphite.
6. The electrode according to claim 1 , wherein the first film comprises a region with a thickness of 2 nm or more and 20 nm or less.
7. The electrode according to claim 1 , wherein the first binder is a cellulose derivative.
8. The electrode according to claim 1 ,
A
=
b
+
c
a
+
b
+
c
×
100
÷
S
[
Mathematical
Formula
1
]
wherein A defined by Mathematical Formula 1 is 1 or more,
wherein S [m 2 /g] is a specific surface area of the active material
wherein a [g] is a weight of the active material,
wherein b [g] is a weight of the first binder, and
wherein c [g] is a weight of the second binder.
9. The electrode according to claim 8 ,
B
=
b
a
+
b
+
c
×
100
÷
S
[
Mathematical
Formula
2
]
wherein B defined by Mathematical Formula 2 is 0.3 or more.
10. A power storage device comprising:
a positive electrode;
a negative electrode comprising:
a negative active material comprising an active material particle;
a first film covering the active material particle, the first film comprising a first binder and a second binder;
a second film covering the active material particle and the first film, the second film comprising Li, F, O and C; and
an electrolyte,
wherein a first portion of the second film is in contact with the first film,
wherein a second portion of the second film is in contact with the active material particle,
wherein the first binder is a water-soluble polymer,
wherein a thickness of the first portion of the second film is thinner than a thickness of the second portion of the second film.
11. The power storage device according to claim 10 , wherein the second binder comprises a double bond which is capable of reacting with osmium tetroxide.
12. The power storage device according to claim 10 , wherein the second binder comprises a stylene monomer unit.
13. The power storage device according to claim 10 , wherein the second binder further comprises a butadiene monomer unit.
14. The power storage device according to claim 10 , wherein a material of the active material particle is graphite.
15. The power storage device according to claim 10 , wherein the first film comprises a region with a thickness of 2 nm or more and 20 nm or less.
16. The power storage device according to claim 10 , wherein the first binder is a cellulose derivative.
17. The power storage device according to claim 10 ,
A
=
b
+
c
a
+
b
+
c
×
100
÷
S
[
Mathematical
Formula
1
]
wherein A defined by Mathematical Formula 1 is 1 or more,
wherein S [m 2 /g] is a specific surface area of the negative active material,
wherein a [g] is a weight of the negative active material,
wherein b [g] is a weight of the first binder, and
wherein c [g] is a weight of the second binder.
18. The power storage device according to claim 17 ,
B
=
b
a
+
b
+
c
×
100
÷
S
[
Mathematical
Formula
2
]
wherein B defined by Mathematical Formula 2 is 0.3 or more.
19. The power storage device according to claim 10 , wherein the second film is made by decomposition of the electrolyte.