Abstract: The present invention relates to an electrochemical device and a manufacturing method therefor. More specifically, the present invention relates to an electrochemical device in which, in an electrode assembly composed of a cathode, a separator, and an anode, at least one or more of the cathode, the separator, and the anode are formed of a gel polymer electrolyte and have different ion conductivities, and a manufacturing method therefor. Since the electrochemical device of the present invention includes electrolytes having different ion conductivities in at least one of the cathode, the separator, and the anode, it is possible to provide the optimized flow of ions for the separator and each electrode. Accordingly, the present invention has advantageous effects in improving the lifespan and safety of the electrochemical device.

Abstract: Provided is a composite separator for an electrochemical device, and the composite separator according to the present invention includes a porous substrate and a crystalline metal salt. The composite separator may serve as a salt source to a liquid electrolyte of the electrochemical device, and additionally or independently, may have flame retardancy by the metal salt.