The prodn. comprises stacking a first current collector, a first electrode, an electrolytic separator, a second electrode, a second current collector and an encapsulating agent, and (i) a conductive ionic screen printing ink is prepd. comprising an intimate mixt. of (a) an ionically conductive polymer, (b) a soluble salt which is dissociated in the polymer and (c) a solvent with a low vapour pressure in which the polymer (a) and the soluble salt (b) are soluble; (ii) to fabricate the electrode(s), a homogeneous powdered mixt. of an electrochemically active material (I) and an electronically conductive material (II) in an amt. of 0-30 wt.% w.r.t. the (I) is incorporated into the conductive ionic ink (i); (iii) the first electrode is obtd. by screen printing layer(s) of the compsn. (ii) onto the first current collector; and (iv) the electrolytic separator is obtd. by screen printing layer(s) of the conductive ionic screen printing ink onto the first electrode.    Pref. the second electrode is formed on the electrolytic separator by screen printing. The encapsulating material is pref. also applied by screen printing over the stack.    The conductive ionic polymer is pref. of linear polymers and crosslinkable polymers e.g. in EP-424827, and esp. a polyether oxide. The ionic salt is used e.g. in an amt. of 0.1-2 moles per litre of polymer. The solvent is of e.g. propylene or butylene carbonate, terpineol, glycol derivs. and mixts. of these. (I) for a super condenser is e.g. carbonaceous material with a high specific surface, metalic oxides and electroconductive polymers. (I) for the cathode of an electrochemical generator with a carbon or Li anode is of e.g. metallic oxides, selenides, (phospho) sulphides or oxyhalides or electroconductive polymers. (II) is of e.g. metallic and carbonaceous materials.    USE/ADVANTAGE -   The electrochemical generators and supercondensers may be fabricated in situ by screen printing onto flexible or rigid substrates e.g. electronic circuit boards. Use of screen printing allows the devices to be made very thin (e.g. with layer thicknesses of less than 10 microns) and with any pref. shape, and is very useful for automated prodn. techniques.