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

This application provides a separator, a preparation method of the separator, a secondary battery containing the separator, and an electrical device. The separator includes: a porous separator substrate; and a pressure-sensitive coating applied onto at least one surface of the separator substrate. The pressure-sensitive coating includes a first organic particle at a mass percent of 40 wt% to 90 wt%, a pressure-sensitive binder polymer at a mass percent of 10 wt% to 20 wt%, and optionally a second organic particle at a mass percent of 0 wt% to 50 wt%. The pressure-sensitive binder polymer includes a binder polymer and a plasticizer. The separator according to this application is of high ion-conductivity and high bonding performance at a normal temperature. The separator does not exert a bonding action under a pressure less than or equal to 1 MPa, but exerts a substantial bonding action under a pressure greater than or equal to 2 MPa, thereby significantly improving structural stability and ionic conductance of the electrochemical device.