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 core layer structure and a shell layer structure provided on a surface of the core layer structure, where the core layer structure includes a polyacrylate polymer, and the shell layer structure includes a polyvinylidene fluoride polymer. Polyvinylidene fluoride is a homopolymer with a crystallinity of about 50%, resulting in insufficient adhesion force. Therefore, in this application, the polyvinylidene fluoride polymer is used to encapsulate the polyacrylate polymer to obtain the core-shell-structured binder, so that the crystallinity of the polyvinylidene fluoride polymer in the core-shell-structured binder is improved, and adhesion performance of the core-shell-structured binder is improved, thereby increasing adhesion force between a separator and an electrode plate by the binder.