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 [m2/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.