The present invention relates to a process for the production of a capacitor, comprising the process steps: a) the provision of an electrode body (1) of an electrode material (2), wherein a dielectric (3) covers one surface (4) of this electrode material (2) at least partly to form an anode body (5); b) bringing into contact the anode body (5) with a liquid composition comprising3,4- ethylenedioxythiophene, at least one additive and at least one solvent, wherein the boiling point (1013 mbar) of the at least one additive is at least 50°C higher than the boiling point (1013 mbar) of the at least one solvent, or wherein the at least one additive has a molecular weight of at least 200 g/mol and wherein ii) the weight ratio additive : 3,4-ethylenedioxythiophene in the liquid composition is > 0.3, iii) the weight ratio (3,4-ethylenedioxythiophene + additive) : solvent is≤ 1, and iv) the liquid composition contains less than 1000 ppm, based on the weight of 3,4- ethylenedioxythiophene, of an oxidizing agent; c) at least partial removal of the solvent; d) bringing into contact the anode body (5) with at least one oxidizing agent; e) in situ polymerization of 3,4-ethylenedioxythiophene. The present invention also relates to the capacitor obtainable by this process, a reaction solution, an electronic circuit and the use of capacitors.