SEPARATOR, PREPARATION METHOD THEREFOR, SECONDARY BATTERY, AND ELECTRIC DEVICE

Provided in the present application are a separator and a preparation method therefor, a secondary battery, and an electric device. The separator includes a first substrate, a second substrate, a first bonding layer, and a second bonding layer, where the first bonding layer is located between the first substrate and the second substrate, and the first bonding layer includes a first binder; and the second bonding layer is located on one side of the first substrate and/or the second substrate facing away from the first bonding layer, and the second bonding layer includes a second binder. If the thickness of the first bonding layer is denoted as T1 and the thickness of the second bonding layer is denoted as T2, the separator satisfies: T1/T2>1.