Secondary battery electrode, and method for producing same
摘要
說明書
Specifically, the porosity between the surface region and the central region of the film may be substantially the same, based on the cross section of the active material film. For a ratio of a difference between porosity (P1) in the surface region and porosity (P2) in the central region (absolute value of P1?P2) divided by porosity in the central region, based on the cross section of the active material film, uniform porosity may be the ratio of 10% or less, substantially 8% or less, and more substantially 5% or less, and as an example, the two porosities may be substantially the same. Here, substantially the same means the same within a measurement error range. Experimentally, the porosity of the active material film cross section may be an area occupied by pores per unit area of the thickness cross section, in the thickness cross section across the center of the active material film. Here, the surface region may mean a region from the surface to 0.2t0, based on the thickness (t0) of the active material film, and the central region may mean a region to 0.1t0 to each of the upper portion and the lower portion (region from 0.4t0 to 0.6t0), based on the center in the thickness cross section (centerline, imaginary line of 0.5t0). In addition, the porosity in the surface region may mean the porosity in each of the two surfaces, as well as one optional surface of the two surfaces opposing each other. Experimentally, the porosity based on the thickness cross section may be calculated using cross section observation image by a scanning electron microscope and the like.
