Abstract: The invention relates to a process for producing a separator comprising the steps of: providing a sheetlike porous substrate, a solvent, ceramic particles and an adhesion promoter; preparing a slip by mixing the solvent, the adhesion promoter and the ceramic particles; coating the substrate with the slip and thermally drying the coated substrate to obtain the separator. The problem addressed is that of specifying a process useful for producing separators having a higher ceramic content. The problem is solved when the solvent used is a mixture of water and at least one organic component; the adhesion promoter used is a mixture of silanes and at least one thermally crosslinkable acrylic polymer; the slip is admixed with a carboxylic acid preparation and also with a defoamer component free from silicone oil.