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:
a current collector;
an active material;
a first film in contact with the active material, the first film containing a first binder and a second binder, and
a second film overlapping the active material with the first film interposed therebetween at a first portion of the second film and in contact with the active material at a second portion of the second film,
wherein a thickness of the second film at the first portion of the second film is thinner than a thickness of the second film at the second portion of the second film,
wherein the first binder is a water-soluble polymer,
wherein the second film contains lithium, fluorine, oxygen, and carbon,
wherein a specific surface area of the active material is S [m 2 /g],
wherein a weight of the active material, a weight of the first binder, and a weight of the second binder are a, b, and c, respectively, and
wherein A defined by Mathematical Formula 1 is 0.3 or more.
A
=
b
+
c
a
+
b
+
c
×
100
÷
S
[
Mathematical
Formula
1
]
2. The electrode according to claim 1 ,
wherein the first film includes a region with a thickness of 2 nm or more and 20 nm or less.
3. The electrode according to claim 1 ,
wherein the active material is in a form of particles, and
wherein the specific surface area S of the active material is greater than or equal to 0.2 m 2 /g and less than or equal to 7.0 m 2 /g.
4. The electrode according to claim 1 , wherein the first binder contains carboxymethyl cellulose, methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, or diacetyl cellulose.
5. The electrode according to claim 1 , wherein the second binder contains a styrene monomer or a butadiene monomer.
6. The electrode according to claim 1 , wherein the active material contains graphite.
7. A power storage device comprising:
the electrode according to claim 1 ; and
a second electrode,
wherein the electrode has a function of operating as one of a positive electrode and a negative electrode, and
wherein the second electrode has a function of operating as the other of the positive electrode and the negative electrode.
8. An electronic device comprising the power storage device according to claim 7 and a display device.
9. An electrode comprising:
a current collector;
an active material;
a first film in contact with the active material, the first film containing a first binder and a second binder, and
a second film overlapping the active material with the first film interposed therebetween at a first portion of the second film and in contact with the active material at a second portion of the second film,
wherein a thickness of the second film at the first portion of the second film is thinner than a thickness of the second film at the second portion of the second film,
wherein the first binder is a water-soluble polymer,
wherein the second film contains lithium, fluorine, oxygen, and carbon,
wherein a specific surface area of the active material is S [m 2 /g],
wherein a weight of the active material, a weight of the first binder, and a weight of the second binder are a, b, and c, respectively, and
wherein B defined by Mathematical Formula 2 is 0.3 or more.
A
=
b
+
c
a
+
b
+
c
×
100
÷
S
[
Mathematical
Formula
1
]
10. The electrode according to claim 9 , further comprising:
wherein the first film includes a region with a thickness of 2 nm or more and 20 nm or less.
11. The electrode according to claim 9 ,
wherein the active material is in a form of particles, and
wherein the specific surface area S of the active material is greater than or equal to 0.2 m 2 /g and less than or equal to 7.0 m 2 /g.
12. The electrode according to claim 9 , wherein the first binder contains carboxymethyl cellulose, methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, or diacetyl cellulose.
13. The electrode according to claim 9 , wherein the second binder contains a styrene monomer or a butadiene monomer.
14. The electrode according to claim 9 , wherein the active material contains graphite.
15. A power storage device comprising:
the electrode according to claim 9 ; and
a second electrode,
wherein the electrode has a function of operating as one of a positive electrode and a negative electrode, and
wherein the second electrode has a function of operating as the other of the positive electrode and the negative electrode.
16. An electronic device comprising the power storage device according to claim 15 and a display device.
17. An electrode comprising:
an active material;
a first film in contact with the active material, the first film containing a first binder and a second binder, and
a second film overlapping the active material with the first film interposed therebetween at a first portion of the second film and in contact with the active material at a second portion of the second film,
wherein a thickness of the second film at the first portion of the second film is thinner than a thickness of the second film at the second portion of the second film,
wherein the first binder is a water-soluble polymer, and
wherein the second film contains lithium, fluorine, oxygen, and carbon.
18. The electrode according to claim 17 ,
wherein the first film includes a region with a thickness of 2 nm or more and 20 nm or less.
19. The electrode according to claim 17 , wherein the first binder contains carboxymethyl cellulose, methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, or diacetyl cellulose.
20. The electrode according to claim 17 , wherein the second binder contains a styrene monomer or a butadiene monomer.
21. The electrode according to claim 17 , wherein the active material contains graphite.
22. A power storage device comprising:
the electrode according to claim 17 ; and
a second electrode,
wherein the electrode has a function of operating as one of a positive electrode and a negative electrode, and
wherein the second electrode has a function of operating as the other of the positive electrode and the negative electrode.
23. An electronic device comprising the power storage device according to claim 22 and a display device.