Composites bodies used as separators in electrochemical cells

A composite comprising at least one layer which comprises a composition comprising

• (a) from 1 to 99% by weight of a solid (I) with a primary particle size of from 5 nm to 100 μm or a mixture made from at least two solids,
• (b) from 99 to 1% by weight of a polymeric binder (II) which includes:
• (IIa) from 1 to 100% by weight of a polymer or copolymer (IIa) which has, along the chain, terminally and/or laterally, reactive groups (RG) which are capable of crosslinking reactions when exposed to heat and/or UV radiation, and
• (IIb) from 0 to 99% by weight of at least one polymer or copolymer (IIb) which is free from reactive groups RG,
• where the at least one layer has been applied to at least one second layer comprising at least one conventional separator, characterized in that the conventional seperator is selected from the group consisting of:
• separators based on microporous polyolefin films;
• microporous polytetrafluoroethylene (PTFE) films;
• webs, fibers, and nonwovens, all of which can be produced using fibrous polymer materials;
• Nafion® films;
• films based on a copolymer of vinylidene difluoride and hexafluoropropene;
• homopolymers, block polymers and copolymers which in each case contain filler and can be obtained by extrusion, prepared from olefinic hydrocarbons, aromatic hydrocarbons, acrylates or methacrylates, acrylonitrile, methacrylonitrile, N-methylpyrrolidone, N-vinylimidazole, vinyl acetate, vinyl ethers, or halogen-containing olefinic compounds, where the solids (I) are used as fillers in these polymers.