This application relates to the field of battery technologies, and in particular, to a binder and a preparation method thereof, and a separator, electrode assembly, battery cell, battery, and electric apparatus containing such binder. The binder includes a capsule and a core material provided in the capsule, where the capsule includes an organic polymer, and the core material includes a plasticizer. The plasticizer is encapsulated as the core material inside the capsule of the organic polymer to improve adhesion performance of the organic polymer, so as to increase adhesion force between a separator and an electrode plate by the binder.