A separator includes a porous substrate and a first coating located on at least one surface of the porous substrate. The first coating includes a first polymer binder and first inorganic particles, and the first polymer binder comprising core-shell structured particles. 0.3×Dv50 of the first polymer binder≤Dv50 of the first inorganic particles≤0.7×Dv50 of the first polymer binder. Dv50 represents a particle size which reaches 50% of a cumulative volume from a side of small particle size in a granularity distribution on a volume basis The first inorganic particles are used in the first coating, ensuring that the first polymer binder has a bonding function, electrolyte transport is promoted, and the rate performance of the electrochemical device is improved.