The present invention relates to separators for electrochemical cells comprising (A) at least one layer comprising (a) crosslinked polyvinylpyrrolidone in the form of particles, (b) at least one binder, and (c) optionally a base structure, where the mass ratio of the crosslinked polyvinylpyrrolidone in the form of particles (a) to the sum of the mass of the binders (b) in the layer (A) has a value in the range from 99.9:0.1 to 50:50. The present invention further relates to the use of inventive separators and to apparatuses, especially electrochemical cells, comprising inventive separators.