Electrode, power storage device, and electronic device

Abstract

To provide a power storage device with a high capacity. To provide a power storage device with a high energy density. To provide a highly reliable power storage device. To provide a long-life power storage device. To provide an electrode with a high capacity. To provide an electrode with a high energy density. To provide a highly reliable electrode. To provide a long-life electrode. The power storage device includes a first electrode and a second electrode. The first electrode includes a first current collector and a first active material layer. The first active material layer includes a first active material and a first binder. The first active material is graphite. A separation strength F of the first electrode that is measured when the first active material layer is separated from the first current collector after the first electrode is immersed in a solution at a temperature higher than or equal to 20° C. and lower than or equal to 70° C. for longer than or equal to three hours is higher than or equal to 0.05 N/cm and lower than or equal to 5 N/cm per unit width of a sample that is separated.

What is claimed is: 
     
         1 . A power storage device comprising:
 a first electrode; and   a second electrode,   wherein the first electrode includes a first current collector and a first active material layer,   wherein the first active material layer includes a first active material and a first binder,   wherein the first active material is graphite, and   wherein a separation strength F of the first electrode that is measured when the first active material layer is separated from the first current collector after the first electrode is immersed in a solution at a temperature higher than or equal to 20° C. and lower than or equal to 70° C. for longer than or equal to three hours is higher than or equal to 0.05 N/cm and lower than or equal to 5 N/cm per unit width of a sample that is separated.   
     
     
         2 . The power storage device according to  claim 1 ,
 wherein a specific surface area of the graphite is larger than or equal to 0.2 m 2 /g and smaller than or equal to 4 m 2 /g, and   wherein the graphite has a spherical shape or is spherical graphite.   
     
     
         3 . The power storage device according to  claim 1 ,
 wherein the first binder includes a first material and a second material,   wherein the first material includes a diene-based rubber material, and   wherein the second material includes a cellulose derivative.   
     
     
         4 . The power storage device according to  claim 1 ,
 wherein the solution contains a solvent, and   wherein the solvent contains at least one of ethylene carbonate, propylene carbonate, butylene carbonate, chloroethylene carbonate, vinylene carbonate, γ-butyrolactone, γ-valerolactone, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl formate, methyl acetate, methyl butyrate, 1,3-dioxane, 1,4-dioxane, dimethoxyethane, dimethyl sulfoxide, diethyl ether, methyl diglyme, acetonitrile, benzonitrile, tetrahydrofuran, sulfolane, and sultone.   
     
     
         5 . The power storage device according to  claim 1 , further comprising:
 an electrolytic solution,   wherein the electrolytic solution contains a solvent in the solution.   
     
     
         6 . The power storage device according to  claim 1 ,
 wherein the power storage device is configured to be bent,   wherein the second electrode includes a second active material,   wherein the first active material is a negative electrode active material, and   wherein the second active material is a positive electrode active material.   
     
     
         7 . The power storage device according to  claim 6 ,
 wherein a variation ΔT in a volume of the second active material by charge and discharge operations of the power storage device is 10% or less of the smallest volume of the second active material.   
     
     
         8 . An electronic device comprising:
 the power storage device according to  claim 1 .   
     
     
         9 . A power storage device comprising:
 a first electrode; and   a second electrode,   wherein the first electrode includes a first current collector and a first active material layer,   wherein the first active material layer includes a first active material and a first binder,   wherein the first active material contains silicon, and   wherein a separation strength F of the first electrode that is measured when the first active material layer is separated from the first current collector after the first electrode is immersed in a solution at a temperature higher than or equal to 20° C. and lower than or equal to 70° C. for longer than or equal to three hours is higher than or equal to 0.5 N/cm and lower than or equal to 10 N/cm per unit width of a sample that is separated.   
     
     
         10 . The power storage device according to  claim 9 ,
 wherein a variation ΔS in a thickness of the first active material layer by charge and discharge operations of the power storage device is greater than or equal to 25% and less than or equal to 200% of the smallest thickness of the first active material layer.   
     
     
         11 . The power storage device according to  claim 9 ,
 wherein the solution contains a solvent, and   wherein the solvent contains at least one of ethylene carbonate, propylene carbonate, butylene carbonate, chloroethylene carbonate, vinylene carbonate, γ-butyrolactone, γ-valerolactone, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl formate, methyl acetate, methyl butyrate, 1,3-dioxane, 1,4-dioxane, dimethoxyethane, dimethyl sulfoxide, diethyl ether, methyl diglyme, acetonitrile, benzonitrile, tetrahydrofuran, sulfolane, and sultone.   
     
     
         12 . The power storage device according to  claim 9 , further comprising:
 an electrolytic solution,   wherein the electrolytic solution contains a solvent in the solution.   
     
     
         13 . The power storage device according to  claim 9 ,
 wherein the power storage device is configured to be bent,   wherein the second electrode includes a second active material,   wherein the first active material is a negative electrode active material, and   wherein the second active material is a positive electrode active material.   
     
     
         14 . The power storage device according to  claim 13 ,
 wherein a variation ΔT in a volume of the second active material by charge and discharge operations of the power storage device is 10% or less of the smallest volume of the second active material.   
     
     
         15 . An electronic device comprising:
 the power storage device according to  claim 9 .