SEPARATOR, PREPARATION METHOD THEREFOR AND RELATED SECONDARY BATTERY, BATTERY MODULE, BATTERY PACK AND DEVICE

A separator, comprising a substrate and a coating provided on at least one surface of the substrate are provided. In some embodiments, the coating comprises inorganic particles and organic particles, the organic particles comprise first organic particles and second organic particles both embedded in the inorganic particles and forming protrusions on the surface of the coating; the first organic particles are secondary particles, and the number of the first organic particles in the coating is denoted as A; the second organic particles are primary particles and the number of the second organic particles in the coating is denoted as B; with the separator satisfying: 0.05≤A/B